Add all exercises

2022-08-27 16:26:13 +02:00 · 2022-08-27 16:26:13 +02:00 · 35199c438c
commit 35199c438c
29 changed files with 2644 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1,5 @@
+**/build
+**/exe
+**/lst
+
+**/result
--- a/README.md
+++ b/README.md
@ -0,0 +1,24 @@
+# TDT 4160 Solutions Autumn 2021
+
+In order to build this code, you will need to have the following installed:
+
+- Simplicity Studio
+- The `EFM32GG-STK3700` adapter for Simplicity Studio
+- GNU Make (haven't tested BSD Make)
+
+For the assembly and C exercises, I'm using the makefile to build and flash the program to the Gecko Board.
+
+```bash
+cd o1 # or o2 / o3
+make all
+make flash
+```
+
+In order for the commands above to succeed, you might need to edit the makefile to point at your Simplicity Studio install.
+The original makefile expected Simplicity Studio 3.
+The paths is currently configured to point at Simplicity Studio 5, installed at `/opt/simplicitystudio5`.
+The original makefiles are stored as `Makefile.original`, in order to make them easy to diff.
+
+## Assembly cheatsheet from Azeria Labs
+
+![azeria-labs.com](https://azeria-labs.com/downloads/cheatsheetv1.3-1920x1080.png)
--- a/kompendium_o123.pdf
+++ b/kompendium_o123.pdf
--- a/o1/Makefile
+++ b/o1/Makefile
@ -0,0 +1,214 @@
+####################################################################
+# Makefile                                                         #
+####################################################################
+
+.SUFFIXES:				# ignore builtin rules
+.PHONY: all debug release clean flash rammeverk 
+
+####################################################################
+# Definitions                                                      #
+####################################################################
+
+# notdirx: version of notdir which allows spaces in path
+s? = $(subst $(empty) ,?,$1)
+?s = $(subst ?, ,$1)
+notdirx = $(call ?s,$(notdir $(call s?,$1)))
+
+DEVICE = EFM32GG990F1024
+PROJECTNAME = $(call notdirx,$(CURDIR))
+
+OBJ_DIR = build
+EXE_DIR = exe
+LST_DIR = lst
+
+
+####################################################################
+# Definitions of toolchain.                                        #
+# You might need to do changes to match your system setup          #
+####################################################################
+
+RM         := rm -rf
+NULLDEVICE := /dev/null
+SHELLNAMES := $(ComSpec)$(COMSPEC)
+
+# This is only valid for my specific system.
+TOOLCHAIN_BIN_DIR := /opt/simplicitystudio5/developer/toolchains/gnu_arm/10.2_2020q4/bin
+
+CC         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-gcc
+LD         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-ld
+AR         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-ar
+OBJCOPY    := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-objcopy
+DUMP       := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-objdump
+
+# Detect operating system
+ifeq ($(SHELLNAMES),)           # Linux
+  EACOM = /opt/simplicitystudio5/developer/adapter_packs/commander/commander
+else
+  EACOM = C:\SiliconLabs\SimplicityStudio\v3\bgtool\commander\commander.exe
+  ifneq ($(COMSPEC),)           # mingw/msys/cygwin platform running on Windows
+    ifeq ($(findstring cygdrive,$(shell set)),)
+      # We were not on a cygwin platform
+      NULLDEVICE := NUL
+    endif
+  else                          # Windows
+    NULLDEVICE := NUL
+  endif
+endif
+
+# Create directories and do a clean which is compatible with parallell make
+$(shell mkdir $(OBJ_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(EXE_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(LST_DIR)>$(NULLDEVICE) 2>&1)
+ifeq (clean,$(findstring clean, $(MAKECMDGOALS)))
+  ifneq ($(filter $(MAKECMDGOALS),all debug release),)
+    $(shell $(RM) $(OBJ_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(EXE_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(LST_DIR)/*>$(NULLDEVICE) 2>&1) #*/
+  endif
+endif
+
+####################################################################
+# Flags                                                            #
+####################################################################
+
+# -MMD : Don't generate dependencies on system header files.
+# -MP  : Add phony targets, useful when a h-file is removed from a project.
+# -MF  : Specify a file to write the dependencies to.
+DEPFLAGS = -MMD -MP -MF $(@:.o=.d)
+
+#
+# Add -Wa,-ahld=$(LST_DIR)/$(@F:.o=.lst) to CFLAGS to produce assembly list files
+#
+override CFLAGS += -D$(DEVICE) -Wall -Wextra -mcpu=cortex-m3 -mthumb -ffunction-sections \
+-fdata-sections -mfix-cortex-m3-ldrd -fomit-frame-pointer -DDEBUG_EFM       \
+-O0 \
+$(DEPFLAGS)
+
+ASMFLAGS += -x assembler-with-cpp -mcpu=cortex-m3 -mthumb
+
+#
+# NOTE: The -Wl,--gc-sections flag may interfere with debugging using gdb.
+#
+override LDFLAGS += -Xlinker -Map=$(LST_DIR)/$(PROJECTNAME).map -mcpu=cortex-m3 \
+-mthumb -Tefm32gg.ld --specs=nano.specs \
+ -Wl,--gc-sections
+
+LIBS = -Wl,--start-group -lgcc -lc -lnosys -Wl,--end-group
+
+INCLUDEPATHS += \
+-I.. \
+-I../common/CMSIS/Include \
+-I../common/EFM32GG/Include \
+-I../common/emlib/inc \
+-I../common/EFM32/drivers \
+-I../common/EFM32/bsp \
+-I../common/EFM32GG_STK3700/config
+
+####################################################################
+# Files                                                            #
+####################################################################
+
+C_SRC +=  \
+../common/EFM32GG/Source/system_efm32gg.c \
+../common/EFM32/drivers/vddcheck.c \
+../common/EFM32/drivers/segmentlcd.c \
+../common/emlib/src/em_assert.c \
+../common/emlib/src/em_cmu.c \
+../common/emlib/src/em_emu.c \
+../common/emlib/src/em_gpio.c \
+../common/emlib/src/em_rtc.c \
+../common/emlib/src/em_system.c \
+../common/emlib/src/em_lcd.c \
+../common/emlib/src/em_vcmp.c \
+../common/emlib/src/em_usart.c \
+../common/EFM32/bsp/bsp_stk.c \
+../common/EFM32/bsp/bsp_stk_leds.c \
+../common/EFM32/bsp/bsp_trace.c \
+../common/$(PROJECTNAME)/init.c
+
+s_SRC +=  \
+../common/EFM32GG/Source/GCC/startup_efm32gg.s
+
+STUDENT_SRC += \
+$(PROJECTNAME).s \
+gpio_constants.s \
+sys-tick_constants.s
+
+####################################################################
+# Rules                                                            #
+####################################################################
+
+C_FILES = $(notdir $(C_SRC) )
+S_FILES = $(notdir $(S_SRC) $(s_SRC) )
+#make list of source paths, sort also removes duplicates
+C_PATHS = $(sort $(dir $(C_SRC) ) )
+S_PATHS = $(sort $(dir $(S_SRC) $(s_SRC) ) )
+
+C_OBJS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.o))
+S_OBJS = $(if $(S_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.S=.o)))
+s_OBJS = $(if $(s_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.s=.o)))
+C_DEPS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.d))
+OBJS = $(C_OBJS) $(S_OBJS) $(s_OBJS)
+STUDENT_OBJS = $(addprefix $(OBJ_DIR)/, $(STUDENT_SRC:.s=.o))
+
+vpath %.c $(C_PATHS)
+vpath %.s $(S_PATHS)
+vpath %.S $(S_PATHS)
+
+
+# Default build is debug build
+all:      debug
+
+debug:    CFLAGS += -DDEBUG -O0 -g3
+debug:    $(EXE_DIR)/$(PROJECTNAME).bin
+
+release:  CFLAGS += -DNDEBUG -O3 -g3 
+release:  $(EXE_DIR)/$(PROJECTNAME).bin
+
+rammeverk:  $(OBJS)
+
+# Create objects from C SRC files
+$(OBJ_DIR)/%.o: %.c
+	@echo "Building file: $<"
+	$(CC) $(CFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Assemble .s/.S files
+$(OBJ_DIR)/%.o: %.s
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+$(OBJ_DIR)/%.o: %.S
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Link
+$(EXE_DIR)/$(PROJECTNAME).out: $(STUDENT_OBJS) 
+	@echo "Linking target: $@"
+	$(CC) $(LDFLAGS) $(OBJS) $(STUDENT_OBJS) $(LIBS) -o $(EXE_DIR)/$(PROJECTNAME).out
+
+# Create binary file
+$(EXE_DIR)/$(PROJECTNAME).bin: $(EXE_DIR)/$(PROJECTNAME).out
+	@echo "Creating binary file"
+	$(OBJCOPY) -O binary $(EXE_DIR)/$(PROJECTNAME).out $(EXE_DIR)/$(PROJECTNAME).bin
+# Uncomment next line to produce assembly listing of entire program
+#	$(DUMP) -h -S -C $(EXE_DIR)/$(PROJECTNAME).out>$(LST_DIR)/$(PROJECTNAME)out.lst
+
+# Flash on!
+ifeq ($(f), 1)
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+endif
+
+clean:
+ifeq ($(filter $(MAKECMDGOALS),all debug release),)
+	$(RM) $(LST_DIR) $(EXE_DIR)
+	$(RM) $(STUDENT_OBJS)
+endif
+
+# include auto-generated dependency files (explicit rules)
+ifneq (clean,$(findstring clean, $(MAKECMDGOALS)))
+-include $(C_DEPS)
+endif
+
+flash:
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+	@echo "Completed!"
--- a/o1/Makefile.original
+++ b/o1/Makefile.original
@ -0,0 +1,214 @@
+####################################################################
+# Makefile                                                         #
+####################################################################
+
+.SUFFIXES:				# ignore builtin rules
+.PHONY: all debug release clean flash rammeverk 
+
+####################################################################
+# Definitions                                                      #
+####################################################################
+
+# notdirx: version of notdir which allows spaces in path
+s? = $(subst $(empty) ,?,$1)
+?s = $(subst ?, ,$1)
+notdirx = $(call ?s,$(notdir $(call s?,$1)))
+
+DEVICE = EFM32GG990F1024
+PROJECTNAME = $(call notdirx,$(CURDIR))
+
+OBJ_DIR = build
+EXE_DIR = exe
+LST_DIR = lst
+
+
+####################################################################
+# Definitions of toolchain.                                        #
+# You might need to do changes to match your system setup          #
+####################################################################
+
+RM         := rm -rf
+NULLDEVICE := /dev/null
+SHELLNAMES := $(ComSpec)$(COMSPEC)
+
+CC         := arm-none-eabi-gcc
+LD         := arm-none-eabi-ld
+AR         := arm-none-eabi-ar
+OBJCOPY    := arm-none-eabi-objcopy
+DUMP       := arm-none-eabi-objdump
+
+# Detect operating system
+ifeq ($(SHELLNAMES),)           # Linux
+  EACOM = /opt/SimplicityStudio_v3/bgtool/commander/commander
+else
+  EACOM = C:\SiliconLabs\SimplicityStudio\v3\bgtool\commander\commander.exe
+  ifneq ($(COMSPEC),)           # mingw/msys/cygwin platform running on Windows
+    ifeq ($(findstring cygdrive,$(shell set)),)
+      # We were not on a cygwin platform
+      NULLDEVICE := NUL
+    endif
+  else                          # Windows
+    NULLDEVICE := NUL
+  endif
+endif
+
+# Create directories and do a clean which is compatible with parallell make
+$(shell mkdir $(OBJ_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(EXE_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(LST_DIR)>$(NULLDEVICE) 2>&1)
+ifeq (clean,$(findstring clean, $(MAKECMDGOALS)))
+  ifneq ($(filter $(MAKECMDGOALS),all debug release),)
+    $(shell $(RM) $(OBJ_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(EXE_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(LST_DIR)/*>$(NULLDEVICE) 2>&1) #*/
+  endif
+endif
+
+
+
+
+####################################################################
+# Flags                                                            #
+####################################################################
+
+# -MMD : Don't generate dependencies on system header files.
+# -MP  : Add phony targets, useful when a h-file is removed from a project.
+# -MF  : Specify a file to write the dependencies to.
+DEPFLAGS = -MMD -MP -MF $(@:.o=.d)
+
+#
+# Add -Wa,-ahld=$(LST_DIR)/$(@F:.o=.lst) to CFLAGS to produce assembly list files
+#
+override CFLAGS += -D$(DEVICE) -Wall -Wextra -mcpu=cortex-m3 -mthumb -ffunction-sections \
+-fdata-sections -mfix-cortex-m3-ldrd -fomit-frame-pointer -DDEBUG_EFM       \
+-O0 \
+$(DEPFLAGS)
+
+ASMFLAGS += -x assembler-with-cpp -mcpu=cortex-m3 -mthumb
+
+#
+# NOTE: The -Wl,--gc-sections flag may interfere with debugging using gdb.
+#
+override LDFLAGS += -Xlinker -Map=$(LST_DIR)/$(PROJECTNAME).map -mcpu=cortex-m3 \
+-mthumb -Tefm32gg.ld --specs=nano.specs \
+ -Wl,--gc-sections
+
+LIBS = -Wl,--start-group -lgcc -lc -lnosys -Wl,--end-group
+
+INCLUDEPATHS += \
+-I.. \
+-I../common/CMSIS/Include \
+-I../common/EFM32GG/Include \
+-I../common/emlib/inc \
+-I../common/EFM32/drivers \
+-I../common/EFM32/bsp \
+-I../common/EFM32GG_STK3700/config
+
+####################################################################
+# Files                                                            #
+####################################################################
+
+C_SRC +=  \
+../common/EFM32GG/Source/system_efm32gg.c \
+../common/EFM32/drivers/vddcheck.c \
+../common/EFM32/drivers/segmentlcd.c \
+../common/emlib/src/em_assert.c \
+../common/emlib/src/em_cmu.c \
+../common/emlib/src/em_emu.c \
+../common/emlib/src/em_gpio.c \
+../common/emlib/src/em_rtc.c \
+../common/emlib/src/em_system.c \
+../common/emlib/src/em_lcd.c \
+../common/emlib/src/em_vcmp.c \
+../common/emlib/src/em_usart.c \
+../common/EFM32/bsp/bsp_stk.c \
+../common/EFM32/bsp/bsp_stk_leds.c \
+../common/EFM32/bsp/bsp_trace.c \
+../common/$(PROJECTNAME)/init.c
+
+s_SRC +=  \
+../common/EFM32GG/Source/GCC/startup_efm32gg.s
+
+STUDENT_SRC += \
+$(PROJECTNAME).s \
+gpio_constants.s \
+sys-tick_constants.s
+
+####################################################################
+# Rules                                                            #
+####################################################################
+
+C_FILES = $(notdir $(C_SRC) )
+S_FILES = $(notdir $(S_SRC) $(s_SRC) )
+#make list of source paths, sort also removes duplicates
+C_PATHS = $(sort $(dir $(C_SRC) ) )
+S_PATHS = $(sort $(dir $(S_SRC) $(s_SRC) ) )
+
+C_OBJS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.o))
+S_OBJS = $(if $(S_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.S=.o)))
+s_OBJS = $(if $(s_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.s=.o)))
+C_DEPS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.d))
+OBJS = $(C_OBJS) $(S_OBJS) $(s_OBJS)
+STUDENT_OBJS = $(addprefix $(OBJ_DIR)/, $(STUDENT_SRC:.s=.o))
+
+vpath %.c $(C_PATHS)
+vpath %.s $(S_PATHS)
+vpath %.S $(S_PATHS)
+
+
+# Default build is debug build
+all:      debug
+
+debug:    CFLAGS += -DDEBUG -O0 -g3
+debug:    $(EXE_DIR)/$(PROJECTNAME).bin
+
+release:  CFLAGS += -DNDEBUG -O3 -g3 
+release:  $(EXE_DIR)/$(PROJECTNAME).bin
+
+rammeverk:  $(OBJS)
+
+# Create objects from C SRC files
+$(OBJ_DIR)/%.o: %.c
+	@echo "Building file: $<"
+	$(CC) $(CFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Assemble .s/.S files
+$(OBJ_DIR)/%.o: %.s
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+$(OBJ_DIR)/%.o: %.S
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Link
+$(EXE_DIR)/$(PROJECTNAME).out: $(STUDENT_OBJS) 
+	@echo "Linking target: $@"
+	$(CC) $(LDFLAGS) $(OBJS) $(STUDENT_OBJS) $(LIBS) -o $(EXE_DIR)/$(PROJECTNAME).out
+
+# Create binary file
+$(EXE_DIR)/$(PROJECTNAME).bin: $(EXE_DIR)/$(PROJECTNAME).out
+	@echo "Creating binary file"
+	$(OBJCOPY) -O binary $(EXE_DIR)/$(PROJECTNAME).out $(EXE_DIR)/$(PROJECTNAME).bin
+# Uncomment next line to produce assembly listing of entire program
+#	$(DUMP) -h -S -C $(EXE_DIR)/$(PROJECTNAME).out>$(LST_DIR)/$(PROJECTNAME)out.lst
+
+# Flash on!
+ifeq ($(f), 1)
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+endif
+
+clean:
+ifeq ($(filter $(MAKECMDGOALS),all debug release),)
+	$(RM) $(LST_DIR) $(EXE_DIR)
+	$(RM) $(STUDENT_OBJS)
+endif
+
+# include auto-generated dependency files (explicit rules)
+ifneq (clean,$(findstring clean, $(MAKECMDGOALS)))
+-include $(C_DEPS)
+endif
+
+flash:
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+	@echo "Completed!"
--- a/o1/efm32gg.ld
+++ b/o1/efm32gg.ld
@ -0,0 +1,207 @@
+/* Linker script for Silicon Labs EFM32GG devices                      */
+/*                                                                     */
+/* This file is subject to the license terms as defined in ARM's       */
+/* CMSIS END USER LICENSE AGREEMENT.pdf, governing the use of          */
+/* Example Code.                                                       */
+/*                                                                     */
+/* Copyright 2018 Silicon Laboratories, Inc. http://www.silabs.com     */
+/*                                                                     */
+/* Version 5.5.0 */
+/*                                                                     */
+
+MEMORY
+{
+  FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 1048576
+  RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 131072
+}
+
+/* Linker script to place sections and symbol values. Should be used together
+ * with other linker script that defines memory regions FLASH and RAM.
+ * It references following symbols, which must be defined in code:
+ *   Reset_Handler : Entry of reset handler
+ *
+ * It defines following symbols, which code can use without definition:
+ *   __exidx_start
+ *   __exidx_end
+ *   __copy_table_start__
+ *   __copy_table_end__
+ *   __zero_table_start__
+ *   __zero_table_end__
+ *   __etext
+ *   __data_start__
+ *   __preinit_array_start
+ *   __preinit_array_end
+ *   __init_array_start
+ *   __init_array_end
+ *   __fini_array_start
+ *   __fini_array_end
+ *   __data_end__
+ *   __bss_start__
+ *   __bss_end__
+ *   __end__
+ *   end
+ *   __HeapLimit
+ *   __StackLimit
+ *   __StackTop
+ *   __stack
+ *   __Vectors_End
+ *   __Vectors_Size
+ */
+ENTRY(Reset_Handler)
+
+SECTIONS
+{
+  .text :
+  {
+    KEEP(*(.vectors))
+    __Vectors_End = .;
+    __Vectors_Size = __Vectors_End - __Vectors;
+    __end__ = .;
+
+    *(.text*)
+
+    KEEP(*(.init))
+    KEEP(*(.fini))
+
+    /* .ctors */
+    *crtbegin.o(.ctors)
+    *crtbegin?.o(.ctors)
+    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
+    *(SORT(.ctors.*))
+    *(.ctors)
+
+    /* .dtors */
+    *crtbegin.o(.dtors)
+    *crtbegin?.o(.dtors)
+    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
+    *(SORT(.dtors.*))
+    *(.dtors)
+
+    *(.rodata*)
+
+    KEEP(*(.eh_frame*))
+  } > FLASH
+
+  .ARM.extab :
+  {
+    *(.ARM.extab* .gnu.linkonce.armextab.*)
+  } > FLASH
+
+  __exidx_start = .;
+  .ARM.exidx :
+  {
+    *(.ARM.exidx* .gnu.linkonce.armexidx.*)
+  } > FLASH
+  __exidx_end = .;
+
+  /* To copy multiple ROM to RAM sections,
+   * uncomment .copy.table section and,
+   * define __STARTUP_COPY_MULTIPLE in startup_ARMCMx.S */
+  /*
+  .copy.table :
+  {
+    . = ALIGN(4);
+    __copy_table_start__ = .;
+    LONG (__etext)
+    LONG (__data_start__)
+    LONG (__data_end__ - __data_start__)
+    LONG (__etext2)
+    LONG (__data2_start__)
+    LONG (__data2_end__ - __data2_start__)
+    __copy_table_end__ = .;
+  } > FLASH
+  */
+
+  /* To clear multiple BSS sections,
+   * uncomment .zero.table section and,
+   * define __STARTUP_CLEAR_BSS_MULTIPLE in startup_ARMCMx.S */
+  /*
+  .zero.table :
+  {
+    . = ALIGN(4);
+    __zero_table_start__ = .;
+    LONG (__bss_start__)
+    LONG (__bss_end__ - __bss_start__)
+    LONG (__bss2_start__)
+    LONG (__bss2_end__ - __bss2_start__)
+    __zero_table_end__ = .;
+  } > FLASH
+  */
+
+  __etext = .;
+
+  .data : AT (__etext)
+  {
+    __data_start__ = .;
+    *(vtable)
+    *(.data*)
+    . = ALIGN (4);
+    *(.ram)
+
+    . = ALIGN(4);
+    /* preinit data */
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP(*(.preinit_array))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+
+    . = ALIGN(4);
+    /* init data */
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP(*(SORT(.init_array.*)))
+    KEEP(*(.init_array))
+    PROVIDE_HIDDEN (__init_array_end = .);
+
+    . = ALIGN(4);
+    /* finit data */
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP(*(SORT(.fini_array.*)))
+    KEEP(*(.fini_array))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+
+    KEEP(*(.jcr*))
+    . = ALIGN(4);
+    /* All data end */
+    __data_end__ = .;
+
+  } > RAM
+
+  .bss :
+  {
+    . = ALIGN(4);
+    __bss_start__ = .;
+    *(.bss*)
+    *(COMMON)
+    . = ALIGN(4);
+    __bss_end__ = .;
+  } > RAM
+
+  .heap (COPY):
+  {
+    __HeapBase = .;
+    __end__ = .;
+    end = __end__;
+    _end = __end__;
+    KEEP(*(.heap*))
+    __HeapLimit = .;
+  } > RAM
+
+  /* .stack_dummy section doesn't contains any symbols. It is only
+   * used for linker to calculate size of stack sections, and assign
+   * values to stack symbols later */
+  .stack_dummy (COPY):
+  {
+    KEEP(*(.stack*))
+  } > RAM
+
+  /* Set stack top to end of RAM, and stack limit move down by
+   * size of stack_dummy section */
+  __StackTop = ORIGIN(RAM) + LENGTH(RAM);
+  __StackLimit = __StackTop - SIZEOF(.stack_dummy);
+  PROVIDE(__stack = __StackTop);
+
+  /* Check if data + heap + stack exceeds RAM limit */
+  ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
+
+  /* Check if FLASH usage exceeds FLASH size */
+  ASSERT( LENGTH(FLASH) >= (__etext + SIZEOF(.data)), "FLASH memory overflowed !")
+}
--- a/o1/gpio_constants.s
+++ b/o1/gpio_constants.s
@ -0,0 +1,53 @@
+// GPIO base-adresse
+GPIO_BASE = 0x40006000
+
+// --- [Offset til GPIO-registrene]----------------------------------------- //
+    // --- [Offset til portregistrene ] ------------------------------- //
+        GPIO_PORT_CTRL     =  0     // Port Control Register
+        GPIO_PORT_MODEL    =  4     // Port Pin Mode Low Register
+        GPIO_PORT_MODEH    =  8     // Port Pin Mode High Register
+        GPIO_PORT_DOUT     =  12    // Port Data Out Register
+        GPIO_PORT_DOUTSET  =  16    // Port Data Out Set Register
+        GPIO_PORT_DOUTCLR  =  20    // Port Data Out Clear Register
+        GPIO_PORT_DOUTTGL  =  24    // Port Data Out Toggle Register
+        GPIO_PORT_DIN      =  28    // Port Data In Register
+        GPIO_PORT_PINLOCKN =  32    // Port Unlocked Pins Register
+    // ---------------------------------------------------------------- //
+    
+    GPIO_EXTIPSELL  =  256  // External Interrupt Port Select Low Register
+    GPIO_EXTIPSELH  =  260  // External Interrupt Port Select High Register
+    GPIO_EXTIRISE   =  264  // External Interrupt Rising Edge Trigger Register 
+    GPIO_EXTIFALL   =  268  // External Interrupt Falling Edge Trigger Register 
+    GPIO_IEN        =  272  // Interrupt Enable Register 
+    GPIO_IF         =  276  // Interrupt Flag Register 
+    GPIO_IFS        =  280  // Interrupt Flag Set Register 
+    GPIO_IFC        =  284  // Interrupt Flag Clear Register 
+
+    GPIO_ROUTE      =  288  // I/O Routing Register 
+    GPIO_INSENSE    =  292  // Input Sense Register 
+    GPIO_LOCK       =  296  // Configuration Lock Register 
+    GPIO_CTRL       =  300  // GPIO Control Register 
+    GPIO_CMD        =  304  // EM4 Wake-up Clear Register 
+    GPIO_EM4WUEN    =  308  // EM4 Wake-up Enable Register 
+    GPIO_EM4WUPOL   =  312  // EM4 Wake-up Polarity Register 
+    GPIO_EM4WUCAUSE =  316  // EM4 Wake-up Cause Register 
+// ------------------------------------------------------------------------- //
+
+// --- [Hjelpekonstanter til GPIO]------------------------------------------ //
+    // Porter
+    PORT_A          = 0
+    PORT_B          = 1
+    PORT_C          = 2
+    PORT_D          = 3
+    PORT_E          = 4
+    PORT_F          = 5
+
+    NUMBER_OF_PORTS = 6     // Antall porter
+    PORT_SIZE       = 36    // Antall bytes i et sett med portregistre
+    
+    // Enheter på kitet
+    LED_PORT        = PORT_E
+    LED_PIN         = 2
+    BUTTON_PORT     = PORT_B
+    BUTTON_PIN      = 9
+// ------------------------------------------------------------------------- //
--- a/o1/o1.s
+++ b/o1/o1.s
@ -0,0 +1,27 @@
+.thumb
+.syntax unified
+
+.include "gpio_constants.s"     // Register-adresser og konstanter for GPIO
+
+.text
+	.global Start
+
+LED_PORT_BASE = GPIO_BASE + (LED_PORT * PORT_SIZE)
+LED_SET_ADDR = LED_PORT_BASE  + GPIO_PORT_DOUTSET
+LED_CLEAR_ADDR = LED_PORT_BASE + GPIO_PORT_DOUTCLR
+BUTTON_READ_ADDR = GPIO_BASE + (BUTTON_PORT * PORT_SIZE) + GPIO_PORT_DIN
+	
+Start:
+  LDR R0, =LED_SET_ADDR
+  LDR R1, =LED_CLEAR_ADDR
+  LDR R2, =BUTTON_READ_ADDR
+
+Loop:
+  LDR R3, [R2]                 // Read value of BUTTON_READ_ADDR
+  AND R3, R3, 1 << BUTTON_PIN  // Mask out the bit of interest
+  LSR R3, BUTTON_PIN - LED_PIN // Shift the bit to the LED_PIN position
+  STR R3, [R1]                 // Store the value into LED_SET_ADDR
+  EOR R3, R3, 1 << LED_PIN     // Flip the bit
+  STR R3, [R0]                 // Store the opposite bit into LED_CLEAR_ADDR
+  B Loop                       // Repeat
+  NOP
--- a/o1/sys-tick_constants.s
+++ b/o1/sys-tick_constants.s
@ -0,0 +1,19 @@
+// SysTick Base-addresse    
+SYSTICK_BASE =  0xE000E010
+
+// ---[ Offset til sys-tick-registrene ]------------------------ //
+    SYSTICK_CTRL  = 0   // SysTick Control and Status Register
+    SYSTICK_LOAD  = 4   // SysTick Reload Value Register
+    SYSTICK_VAL   = 8   // SysTick Current Value Register
+    SYSTICK_CALIB = 12  // SysTick Calibration Register
+// ------------------------------------------------------------- //
+
+
+// ---[ Hjelpekonstanter til sys-tick ]------------------------- //
+    FREQUENCY = 14000000   // Antall klokkesignaler per sekund
+
+    // CTRL-register-masker
+    SysTick_CTRL_CLKSOURCE_Msk = 0b100
+    SysTick_CTRL_TICKINT_Msk   = 0b010
+    SysTick_CTRL_ENABLE_Msk    = 0b001
+// ------------------------------------------------------------- //
--- a/o2/Makefile
+++ b/o2/Makefile
@ -0,0 +1,214 @@
+####################################################################
+# Makefile                                                         #
+####################################################################
+
+.SUFFIXES:				# ignore builtin rules
+.PHONY: all debug release clean flash rammeverk 
+
+####################################################################
+# Definitions                                                      #
+####################################################################
+
+# notdirx: version of notdir which allows spaces in path
+s? = $(subst $(empty) ,?,$1)
+?s = $(subst ?, ,$1)
+notdirx = $(call ?s,$(notdir $(call s?,$1)))
+
+DEVICE = EFM32GG990F1024
+PROJECTNAME = $(call notdirx,$(CURDIR))
+
+OBJ_DIR = build
+EXE_DIR = exe
+LST_DIR = lst
+
+
+####################################################################
+# Definitions of toolchain.                                        #
+# You might need to do changes to match your system setup          #
+####################################################################
+
+RM         := rm -rf
+NULLDEVICE := /dev/null
+SHELLNAMES := $(ComSpec)$(COMSPEC)
+
+# This is only valid for my specific system.
+TOOLCHAIN_BIN_DIR := /opt/simplicitystudio5/developer/toolchains/gnu_arm/10.2_2020q4/bin
+
+CC         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-gcc
+LD         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-ld
+AR         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-ar
+OBJCOPY    := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-objcopy
+DUMP       := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-objdump
+
+# Detect operating system
+ifeq ($(SHELLNAMES),)           # Linux
+  EACOM = /opt/simplicitystudio5/developer/adapter_packs/commander/commander
+else
+  EACOM = C:\SiliconLabs\SimplicityStudio\v3\bgtool\commander\commander.exe
+  ifneq ($(COMSPEC),)           # mingw/msys/cygwin platform running on Windows
+    ifeq ($(findstring cygdrive,$(shell set)),)
+      # We were not on a cygwin platform
+      NULLDEVICE := NUL
+    endif
+  else                          # Windows
+    NULLDEVICE := NUL
+  endif
+endif
+
+# Create directories and do a clean which is compatible with parallell make
+$(shell mkdir $(OBJ_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(EXE_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(LST_DIR)>$(NULLDEVICE) 2>&1)
+ifeq (clean,$(findstring clean, $(MAKECMDGOALS)))
+  ifneq ($(filter $(MAKECMDGOALS),all debug release),)
+    $(shell $(RM) $(OBJ_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(EXE_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(LST_DIR)/*>$(NULLDEVICE) 2>&1) #*/
+  endif
+endif
+
+####################################################################
+# Flags                                                            #
+####################################################################
+
+# -MMD : Don't generate dependencies on system header files.
+# -MP  : Add phony targets, useful when a h-file is removed from a project.
+# -MF  : Specify a file to write the dependencies to.
+DEPFLAGS = -MMD -MP -MF $(@:.o=.d)
+
+#
+# Add -Wa,-ahld=$(LST_DIR)/$(@F:.o=.lst) to CFLAGS to produce assembly list files
+#
+override CFLAGS += -D$(DEVICE) -Wall -Wextra -mcpu=cortex-m3 -mthumb -ffunction-sections \
+-fdata-sections -mfix-cortex-m3-ldrd -fomit-frame-pointer -DDEBUG_EFM       \
+-O0 \
+$(DEPFLAGS)
+
+ASMFLAGS += -x assembler-with-cpp -mcpu=cortex-m3 -mthumb
+
+#
+# NOTE: The -Wl,--gc-sections flag may interfere with debugging using gdb.
+#
+override LDFLAGS += -Xlinker -Map=$(LST_DIR)/$(PROJECTNAME).map -mcpu=cortex-m3 \
+-mthumb -Tefm32gg.ld --specs=nano.specs \
+ -Wl,--gc-sections
+
+LIBS = -Wl,--start-group -lgcc -lc -lnosys -Wl,--end-group
+
+INCLUDEPATHS += \
+-I.. \
+-I../common/CMSIS/Include \
+-I../common/EFM32GG/Include \
+-I../common/emlib/inc \
+-I../common/EFM32/drivers \
+-I../common/EFM32/bsp \
+-I../common/EFM32GG_STK3700/config
+
+####################################################################
+# Files                                                            #
+####################################################################
+
+C_SRC +=  \
+../common/EFM32GG/Source/system_efm32gg.c \
+../common/EFM32/drivers/vddcheck.c \
+../common/EFM32/drivers/segmentlcd.c \
+../common/emlib/src/em_assert.c \
+../common/emlib/src/em_cmu.c \
+../common/emlib/src/em_emu.c \
+../common/emlib/src/em_gpio.c \
+../common/emlib/src/em_rtc.c \
+../common/emlib/src/em_system.c \
+../common/emlib/src/em_lcd.c \
+../common/emlib/src/em_vcmp.c \
+../common/emlib/src/em_usart.c \
+../common/EFM32/bsp/bsp_stk.c \
+../common/EFM32/bsp/bsp_stk_leds.c \
+../common/EFM32/bsp/bsp_trace.c \
+../common/$(PROJECTNAME)/init.c
+
+s_SRC +=  \
+../common/EFM32GG/Source/GCC/startup_efm32gg.s
+
+STUDENT_SRC += \
+$(PROJECTNAME).s \
+gpio_constants.s \
+sys-tick_constants.s
+
+####################################################################
+# Rules                                                            #
+####################################################################
+
+C_FILES = $(notdir $(C_SRC) )
+S_FILES = $(notdir $(S_SRC) $(s_SRC) )
+#make list of source paths, sort also removes duplicates
+C_PATHS = $(sort $(dir $(C_SRC) ) )
+S_PATHS = $(sort $(dir $(S_SRC) $(s_SRC) ) )
+
+C_OBJS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.o))
+S_OBJS = $(if $(S_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.S=.o)))
+s_OBJS = $(if $(s_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.s=.o)))
+C_DEPS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.d))
+OBJS = $(C_OBJS) $(S_OBJS) $(s_OBJS)
+STUDENT_OBJS = $(addprefix $(OBJ_DIR)/, $(STUDENT_SRC:.s=.o))
+
+vpath %.c $(C_PATHS)
+vpath %.s $(S_PATHS)
+vpath %.S $(S_PATHS)
+
+
+# Default build is debug build
+all:      debug
+
+debug:    CFLAGS += -DDEBUG -O0 -g3
+debug:    $(EXE_DIR)/$(PROJECTNAME).bin
+
+release:  CFLAGS += -DNDEBUG -O3 -g3 
+release:  $(EXE_DIR)/$(PROJECTNAME).bin
+
+rammeverk:  $(OBJS)
+
+# Create objects from C SRC files
+$(OBJ_DIR)/%.o: %.c
+	@echo "Building file: $<"
+	$(CC) $(CFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Assemble .s/.S files
+$(OBJ_DIR)/%.o: %.s
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+$(OBJ_DIR)/%.o: %.S
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Link
+$(EXE_DIR)/$(PROJECTNAME).out: $(STUDENT_OBJS) 
+	@echo "Linking target: $@"
+	$(CC) $(LDFLAGS) $(OBJS) $(STUDENT_OBJS) $(LIBS) -o $(EXE_DIR)/$(PROJECTNAME).out
+
+# Create binary file
+$(EXE_DIR)/$(PROJECTNAME).bin: $(EXE_DIR)/$(PROJECTNAME).out
+	@echo "Creating binary file"
+	$(OBJCOPY) -O binary $(EXE_DIR)/$(PROJECTNAME).out $(EXE_DIR)/$(PROJECTNAME).bin
+# Uncomment next line to produce assembly listing of entire program
+#	$(DUMP) -h -S -C $(EXE_DIR)/$(PROJECTNAME).out>$(LST_DIR)/$(PROJECTNAME)out.lst
+
+# Flash on!
+ifeq ($(f), 1)
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+endif
+
+clean:
+ifeq ($(filter $(MAKECMDGOALS),all debug release),)
+	$(RM) $(LST_DIR) $(EXE_DIR)
+	$(RM) $(STUDENT_OBJS)
+endif
+
+# include auto-generated dependency files (explicit rules)
+ifneq (clean,$(findstring clean, $(MAKECMDGOALS)))
+-include $(C_DEPS)
+endif
+
+flash:
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+	@echo "Completed!"
--- a/o2/Makefile.original
+++ b/o2/Makefile.original
@ -0,0 +1,214 @@
+####################################################################
+# Makefile                                                         #
+####################################################################
+
+.SUFFIXES:				# ignore builtin rules
+.PHONY: all debug release clean flash rammeverk 
+
+####################################################################
+# Definitions                                                      #
+####################################################################
+
+# notdirx: version of notdir which allows spaces in path
+s? = $(subst $(empty) ,?,$1)
+?s = $(subst ?, ,$1)
+notdirx = $(call ?s,$(notdir $(call s?,$1)))
+
+DEVICE = EFM32GG990F1024
+PROJECTNAME = $(call notdirx,$(CURDIR))
+
+OBJ_DIR = build
+EXE_DIR = exe
+LST_DIR = lst
+
+
+####################################################################
+# Definitions of toolchain.                                        #
+# You might need to do changes to match your system setup          #
+####################################################################
+
+RM         := rm -rf
+NULLDEVICE := /dev/null
+SHELLNAMES := $(ComSpec)$(COMSPEC)
+
+CC         := arm-none-eabi-gcc
+LD         := arm-none-eabi-ld
+AR         := arm-none-eabi-ar
+OBJCOPY    := arm-none-eabi-objcopy
+DUMP       := arm-none-eabi-objdump
+
+# Detect operating system
+ifeq ($(SHELLNAMES),)           # Linux
+  EACOM = /opt/SimplicityStudio_v3/bgtool/commander/commander
+else
+  EACOM = C:\SiliconLabs\SimplicityStudio\v3\bgtool\commander\commander.exe
+  ifneq ($(COMSPEC),)           # mingw/msys/cygwin platform running on Windows
+    ifeq ($(findstring cygdrive,$(shell set)),)
+      # We were not on a cygwin platform
+      NULLDEVICE := NUL
+    endif
+  else                          # Windows
+    NULLDEVICE := NUL
+  endif
+endif
+
+# Create directories and do a clean which is compatible with parallell make
+$(shell mkdir $(OBJ_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(EXE_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(LST_DIR)>$(NULLDEVICE) 2>&1)
+ifeq (clean,$(findstring clean, $(MAKECMDGOALS)))
+  ifneq ($(filter $(MAKECMDGOALS),all debug release),)
+    $(shell $(RM) $(OBJ_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(EXE_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(LST_DIR)/*>$(NULLDEVICE) 2>&1) #*/
+  endif
+endif
+
+
+
+
+####################################################################
+# Flags                                                            #
+####################################################################
+
+# -MMD : Don't generate dependencies on system header files.
+# -MP  : Add phony targets, useful when a h-file is removed from a project.
+# -MF  : Specify a file to write the dependencies to.
+DEPFLAGS = -MMD -MP -MF $(@:.o=.d)
+
+#
+# Add -Wa,-ahld=$(LST_DIR)/$(@F:.o=.lst) to CFLAGS to produce assembly list files
+#
+override CFLAGS += -D$(DEVICE) -Wall -Wextra -mcpu=cortex-m3 -mthumb -ffunction-sections \
+-fdata-sections -mfix-cortex-m3-ldrd -fomit-frame-pointer -DDEBUG_EFM       \
+-O0 \
+$(DEPFLAGS)
+
+ASMFLAGS += -x assembler-with-cpp -mcpu=cortex-m3 -mthumb
+
+#
+# NOTE: The -Wl,--gc-sections flag may interfere with debugging using gdb.
+#
+override LDFLAGS += -Xlinker -Map=$(LST_DIR)/$(PROJECTNAME).map -mcpu=cortex-m3 \
+-mthumb -Tefm32gg.ld --specs=nano.specs \
+ -Wl,--gc-sections
+
+LIBS = -Wl,--start-group -lgcc -lc -lnosys -Wl,--end-group
+
+INCLUDEPATHS += \
+-I.. \
+-I../common/CMSIS/Include \
+-I../common/EFM32GG/Include \
+-I../common/emlib/inc \
+-I../common/EFM32/drivers \
+-I../common/EFM32/bsp \
+-I../common/EFM32GG_STK3700/config
+
+####################################################################
+# Files                                                            #
+####################################################################
+
+C_SRC +=  \
+../common/EFM32GG/Source/system_efm32gg.c \
+../common/EFM32/drivers/vddcheck.c \
+../common/EFM32/drivers/segmentlcd.c \
+../common/emlib/src/em_assert.c \
+../common/emlib/src/em_cmu.c \
+../common/emlib/src/em_emu.c \
+../common/emlib/src/em_gpio.c \
+../common/emlib/src/em_rtc.c \
+../common/emlib/src/em_system.c \
+../common/emlib/src/em_lcd.c \
+../common/emlib/src/em_vcmp.c \
+../common/emlib/src/em_usart.c \
+../common/EFM32/bsp/bsp_stk.c \
+../common/EFM32/bsp/bsp_stk_leds.c \
+../common/EFM32/bsp/bsp_trace.c \
+../common/$(PROJECTNAME)/init.c
+
+s_SRC +=  \
+../common/EFM32GG/Source/GCC/startup_efm32gg.s
+
+STUDENT_SRC += \
+$(PROJECTNAME).s \
+gpio_constants.s \
+sys-tick_constants.s
+
+####################################################################
+# Rules                                                            #
+####################################################################
+
+C_FILES = $(notdir $(C_SRC) )
+S_FILES = $(notdir $(S_SRC) $(s_SRC) )
+#make list of source paths, sort also removes duplicates
+C_PATHS = $(sort $(dir $(C_SRC) ) )
+S_PATHS = $(sort $(dir $(S_SRC) $(s_SRC) ) )
+
+C_OBJS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.o))
+S_OBJS = $(if $(S_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.S=.o)))
+s_OBJS = $(if $(s_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.s=.o)))
+C_DEPS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.d))
+OBJS = $(C_OBJS) $(S_OBJS) $(s_OBJS)
+STUDENT_OBJS = $(addprefix $(OBJ_DIR)/, $(STUDENT_SRC:.s=.o))
+
+vpath %.c $(C_PATHS)
+vpath %.s $(S_PATHS)
+vpath %.S $(S_PATHS)
+
+
+# Default build is debug build
+all:      debug
+
+debug:    CFLAGS += -DDEBUG -O0 -g3
+debug:    $(EXE_DIR)/$(PROJECTNAME).bin
+
+release:  CFLAGS += -DNDEBUG -O3 -g3 
+release:  $(EXE_DIR)/$(PROJECTNAME).bin
+
+rammeverk:  $(OBJS)
+
+# Create objects from C SRC files
+$(OBJ_DIR)/%.o: %.c
+	@echo "Building file: $<"
+	$(CC) $(CFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Assemble .s/.S files
+$(OBJ_DIR)/%.o: %.s
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+$(OBJ_DIR)/%.o: %.S
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Link
+$(EXE_DIR)/$(PROJECTNAME).out: $(STUDENT_OBJS) 
+	@echo "Linking target: $@"
+	$(CC) $(LDFLAGS) $(OBJS) $(STUDENT_OBJS) $(LIBS) -o $(EXE_DIR)/$(PROJECTNAME).out
+
+# Create binary file
+$(EXE_DIR)/$(PROJECTNAME).bin: $(EXE_DIR)/$(PROJECTNAME).out
+	@echo "Creating binary file"
+	$(OBJCOPY) -O binary $(EXE_DIR)/$(PROJECTNAME).out $(EXE_DIR)/$(PROJECTNAME).bin
+# Uncomment next line to produce assembly listing of entire program
+#	$(DUMP) -h -S -C $(EXE_DIR)/$(PROJECTNAME).out>$(LST_DIR)/$(PROJECTNAME)out.lst
+
+# Flash on!
+ifeq ($(f), 1)
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+endif
+
+clean:
+ifeq ($(filter $(MAKECMDGOALS),all debug release),)
+	$(RM) $(LST_DIR) $(EXE_DIR)
+	$(RM) $(STUDENT_OBJS)
+endif
+
+# include auto-generated dependency files (explicit rules)
+ifneq (clean,$(findstring clean, $(MAKECMDGOALS)))
+-include $(C_DEPS)
+endif
+
+flash:
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+	@echo "Completed!"
--- a/o2/efm32gg.ld
+++ b/o2/efm32gg.ld
@ -0,0 +1,207 @@
+/* Linker script for Silicon Labs EFM32GG devices                      */
+/*                                                                     */
+/* This file is subject to the license terms as defined in ARM's       */
+/* CMSIS END USER LICENSE AGREEMENT.pdf, governing the use of          */
+/* Example Code.                                                       */
+/*                                                                     */
+/* Copyright 2018 Silicon Laboratories, Inc. http://www.silabs.com     */
+/*                                                                     */
+/* Version 5.5.0 */
+/*                                                                     */
+
+MEMORY
+{
+  FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 1048576
+  RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 131072
+}
+
+/* Linker script to place sections and symbol values. Should be used together
+ * with other linker script that defines memory regions FLASH and RAM.
+ * It references following symbols, which must be defined in code:
+ *   Reset_Handler : Entry of reset handler
+ *
+ * It defines following symbols, which code can use without definition:
+ *   __exidx_start
+ *   __exidx_end
+ *   __copy_table_start__
+ *   __copy_table_end__
+ *   __zero_table_start__
+ *   __zero_table_end__
+ *   __etext
+ *   __data_start__
+ *   __preinit_array_start
+ *   __preinit_array_end
+ *   __init_array_start
+ *   __init_array_end
+ *   __fini_array_start
+ *   __fini_array_end
+ *   __data_end__
+ *   __bss_start__
+ *   __bss_end__
+ *   __end__
+ *   end
+ *   __HeapLimit
+ *   __StackLimit
+ *   __StackTop
+ *   __stack
+ *   __Vectors_End
+ *   __Vectors_Size
+ */
+ENTRY(Reset_Handler)
+
+SECTIONS
+{
+  .text :
+  {
+    KEEP(*(.vectors))
+    __Vectors_End = .;
+    __Vectors_Size = __Vectors_End - __Vectors;
+    __end__ = .;
+
+    *(.text*)
+
+    KEEP(*(.init))
+    KEEP(*(.fini))
+
+    /* .ctors */
+    *crtbegin.o(.ctors)
+    *crtbegin?.o(.ctors)
+    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
+    *(SORT(.ctors.*))
+    *(.ctors)
+
+    /* .dtors */
+    *crtbegin.o(.dtors)
+    *crtbegin?.o(.dtors)
+    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
+    *(SORT(.dtors.*))
+    *(.dtors)
+
+    *(.rodata*)
+
+    KEEP(*(.eh_frame*))
+  } > FLASH
+
+  .ARM.extab :
+  {
+    *(.ARM.extab* .gnu.linkonce.armextab.*)
+  } > FLASH
+
+  __exidx_start = .;
+  .ARM.exidx :
+  {
+    *(.ARM.exidx* .gnu.linkonce.armexidx.*)
+  } > FLASH
+  __exidx_end = .;
+
+  /* To copy multiple ROM to RAM sections,
+   * uncomment .copy.table section and,
+   * define __STARTUP_COPY_MULTIPLE in startup_ARMCMx.S */
+  /*
+  .copy.table :
+  {
+    . = ALIGN(4);
+    __copy_table_start__ = .;
+    LONG (__etext)
+    LONG (__data_start__)
+    LONG (__data_end__ - __data_start__)
+    LONG (__etext2)
+    LONG (__data2_start__)
+    LONG (__data2_end__ - __data2_start__)
+    __copy_table_end__ = .;
+  } > FLASH
+  */
+
+  /* To clear multiple BSS sections,
+   * uncomment .zero.table section and,
+   * define __STARTUP_CLEAR_BSS_MULTIPLE in startup_ARMCMx.S */
+  /*
+  .zero.table :
+  {
+    . = ALIGN(4);
+    __zero_table_start__ = .;
+    LONG (__bss_start__)
+    LONG (__bss_end__ - __bss_start__)
+    LONG (__bss2_start__)
+    LONG (__bss2_end__ - __bss2_start__)
+    __zero_table_end__ = .;
+  } > FLASH
+  */
+
+  __etext = .;
+
+  .data : AT (__etext)
+  {
+    __data_start__ = .;
+    *(vtable)
+    *(.data*)
+    . = ALIGN (4);
+    *(.ram)
+
+    . = ALIGN(4);
+    /* preinit data */
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP(*(.preinit_array))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+
+    . = ALIGN(4);
+    /* init data */
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP(*(SORT(.init_array.*)))
+    KEEP(*(.init_array))
+    PROVIDE_HIDDEN (__init_array_end = .);
+
+    . = ALIGN(4);
+    /* finit data */
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP(*(SORT(.fini_array.*)))
+    KEEP(*(.fini_array))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+
+    KEEP(*(.jcr*))
+    . = ALIGN(4);
+    /* All data end */
+    __data_end__ = .;
+
+  } > RAM
+
+  .bss :
+  {
+    . = ALIGN(4);
+    __bss_start__ = .;
+    *(.bss*)
+    *(COMMON)
+    . = ALIGN(4);
+    __bss_end__ = .;
+  } > RAM
+
+  .heap (COPY):
+  {
+    __HeapBase = .;
+    __end__ = .;
+    end = __end__;
+    _end = __end__;
+    KEEP(*(.heap*))
+    __HeapLimit = .;
+  } > RAM
+
+  /* .stack_dummy section doesn't contains any symbols. It is only
+   * used for linker to calculate size of stack sections, and assign
+   * values to stack symbols later */
+  .stack_dummy (COPY):
+  {
+    KEEP(*(.stack*))
+  } > RAM
+
+  /* Set stack top to end of RAM, and stack limit move down by
+   * size of stack_dummy section */
+  __StackTop = ORIGIN(RAM) + LENGTH(RAM);
+  __StackLimit = __StackTop - SIZEOF(.stack_dummy);
+  PROVIDE(__stack = __StackTop);
+
+  /* Check if data + heap + stack exceeds RAM limit */
+  ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
+
+  /* Check if FLASH usage exceeds FLASH size */
+  ASSERT( LENGTH(FLASH) >= (__etext + SIZEOF(.data)), "FLASH memory overflowed !")
+}
--- a/o2/gpio_constants.s
+++ b/o2/gpio_constants.s
@ -0,0 +1,53 @@
+// GPIO base-adresse
+GPIO_BASE = 0x40006000
+
+// --- [Offset til GPIO-registrene]----------------------------------------- //
+    // --- [Offset til portregistrene ] ------------------------------- //
+        GPIO_PORT_CTRL     =  0     // Port Control Register
+        GPIO_PORT_MODEL    =  4     // Port Pin Mode Low Register
+        GPIO_PORT_MODEH    =  8     // Port Pin Mode High Register
+        GPIO_PORT_DOUT     =  12    // Port Data Out Register
+        GPIO_PORT_DOUTSET  =  16    // Port Data Out Set Register
+        GPIO_PORT_DOUTCLR  =  20    // Port Data Out Clear Register
+        GPIO_PORT_DOUTTGL  =  24    // Port Data Out Toggle Register
+        GPIO_PORT_DIN      =  28    // Port Data In Register
+        GPIO_PORT_PINLOCKN =  32    // Port Unlocked Pins Register
+    // ---------------------------------------------------------------- //
+    
+    GPIO_EXTIPSELL  =  256  // External Interrupt Port Select Low Register
+    GPIO_EXTIPSELH  =  260  // External Interrupt Port Select High Register
+    GPIO_EXTIRISE   =  264  // External Interrupt Rising Edge Trigger Register 
+    GPIO_EXTIFALL   =  268  // External Interrupt Falling Edge Trigger Register 
+    GPIO_IEN        =  272  // Interrupt Enable Register 
+    GPIO_IF         =  276  // Interrupt Flag Register 
+    GPIO_IFS        =  280  // Interrupt Flag Set Register 
+    GPIO_IFC        =  284  // Interrupt Flag Clear Register 
+
+    GPIO_ROUTE      =  288  // I/O Routing Register 
+    GPIO_INSENSE    =  292  // Input Sense Register 
+    GPIO_LOCK       =  296  // Configuration Lock Register 
+    GPIO_CTRL       =  300  // GPIO Control Register 
+    GPIO_CMD        =  304  // EM4 Wake-up Clear Register 
+    GPIO_EM4WUEN    =  308  // EM4 Wake-up Enable Register 
+    GPIO_EM4WUPOL   =  312  // EM4 Wake-up Polarity Register 
+    GPIO_EM4WUCAUSE =  316  // EM4 Wake-up Cause Register 
+// ------------------------------------------------------------------------- //
+
+// --- [Hjelpekonstanter til GPIO]------------------------------------------ //
+    // Porter
+    PORT_A          = 0
+    PORT_B          = 1
+    PORT_C          = 2
+    PORT_D          = 3
+    PORT_E          = 4
+    PORT_F          = 5
+
+    NUMBER_OF_PORTS = 6     // Antall porter
+    PORT_SIZE       = 36    // Antall bytes i et sett med portregistre
+    
+    // Enheter på kitet
+    LED_PORT        = PORT_E
+    LED_PIN         = 2
+    BUTTON_PORT     = PORT_B
+    BUTTON_PIN      = 9
+// ------------------------------------------------------------------------- //
--- a/o2/o2.s
+++ b/o2/o2.s
@ -0,0 +1,110 @@
+.thumb
+.syntax unified
+
+.include "gpio_constants.s"     // Register-adresser og konstanter for GPIO
+.include "sys-tick_constants.s" // Register-adresser og konstanter for SysTick
+
+.text
+	.global Start
+
+TENTH_SECOND_FREQUENCY = FREQUENCY / 10
+
+SYSTICK_LOAD_BASE = SYSTICK_BASE + SYSTICK_LOAD
+SYSTICK_VAL_BASE  = SYSTICK_BASE + SYSTICK_VAL
+SYSTICK_CTRL_BASE = SYSTICK_BASE + SYSTICK_CTRL
+
+GPIO_EXTIPSELH_BASE = GPIO_BASE + GPIO_EXTIPSELH
+GPIO_EXTIFALL_BASE  = GPIO_BASE + GPIO_EXTIFALL
+GPIO_IEN_BASE       = GPIO_BASE + GPIO_IEN
+GPIO_IFC_BASE       = GPIO_BASE + GPIO_IFC
+GPIO_LED_BASE       = GPIO_BASE + (LED_PORT * PORT_SIZE) + GPIO_PORT_DOUTTGL
+	
+Start:
+
+  LDR R0, =TENTH_SECOND_FREQUENCY
+  LDR R1, =SYSTICK_CTRL_BASE
+  LDR R2, =SYSTICK_LOAD_BASE
+  LDR R3, =SYSTICK_VAL_BASE
+
+  MOV R4, #0b110
+  STR R4, [R1]
+
+  LDR R4, =TENTH_SECOND_FREQUENCY
+  STR R4, [R2]
+
+  MOV R4, #1
+  STR R4, [R3]
+
+  LDR R0, =GPIO_EXTIPSELH_BASE
+  LDR R1, [R0]                 // 0b xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx
+  BFI R1, R4, #4, #4           // 0b xxxx xxxx xxxx xxxx xxxx xxxx 0001 xxxx
+  STR R1, [R0]
+
+	LDR R0, =GPIO_EXTIFALL_BASE
+	LDR R1, [R0]
+	ORR R1, 1 << BUTTON_PIN
+	STR R1, [R0]
+
+	LDR R0, =GPIO_IEN_BASE
+	LDR R1, [R0]
+	ORR R1, 1 << BUTTON_PIN
+	STR R1, [R0]
+
+Loop:
+  WFI
+  B Loop
+
+.global SysTick_Handler
+.thumb_func
+SysTick_Handler:
+
+  LDR R0, =tenths
+  LDR R1, =seconds
+  LDR R2, =minutes
+  LDR R10, [R0]
+  LDR R11, [R1]
+  LDR R12, [R2]
+
+  // Tenth
+  ADD R10, #1
+  CMP R10, #10
+  BNE SysTick_Update
+  MOV R10, 0
+
+  // LED
+	LDR R3, =GPIO_LED_BASE
+	LDR R4, =1<<LED_PIN
+	STR R4, [R3]
+
+  // Second
+  ADD R11, #1
+  CMP R11, #60
+  BNE SysTick_Update
+  MOV R11, 0
+
+  // Minute
+  ADD R12, #1
+
+SysTick_Update:
+  STR R10, [R0]
+  STR R11, [R1]
+  STR R12, [R2]
+  BX LR
+
+.global GPIO_ODD_IRQHandler
+.thumb_func
+GPIO_ODD_IRQHandler:
+
+  LDR R0, =SYSTICK_CTRL_BASE
+  LDR R1, [R0]
+  EOR R1, #1
+  STR R1, [R0]
+
+	LDR R2, =GPIO_IFC_BASE
+  MOV R3, 1 << BUTTON_PIN
+	STR R3, [R2]
+
+  BX LR
+
+
+NOP
--- a/o2/sys-tick_constants.s
+++ b/o2/sys-tick_constants.s
@ -0,0 +1,19 @@
+// SysTick Base-addresse    
+SYSTICK_BASE =  0xE000E010
+
+// ---[ Offset til sys-tick-registrene ]------------------------ //
+    SYSTICK_CTRL  = 0   // SysTick Control and Status Register
+    SYSTICK_LOAD  = 4   // SysTick Reload Value Register
+    SYSTICK_VAL   = 8   // SysTick Current Value Register
+    SYSTICK_CALIB = 12  // SysTick Calibration Register
+// ------------------------------------------------------------- //
+
+
+// ---[ Hjelpekonstanter til sys-tick ]------------------------- //
+    FREQUENCY = 14000000   // Antall klokkesignaler per sekund
+
+    // CTRL-register-masker
+    SysTick_CTRL_CLKSOURCE_Msk = 0b100
+    SysTick_CTRL_TICKINT_Msk   = 0b010
+    SysTick_CTRL_ENABLE_Msk    = 0b001
+// ------------------------------------------------------------- //
--- a/o3/Makefile
+++ b/o3/Makefile
@ -0,0 +1,214 @@
+####################################################################
+# Makefile                                                         #
+####################################################################
+
+.SUFFIXES:				# ignore builtin rules
+.PHONY: all debug release clean flash rammeverk 
+
+####################################################################
+# Definitions                                                      #
+####################################################################
+
+# notdirx: version of notdir which allows spaces in path
+s? = $(subst $(empty) ,?,$1)
+?s = $(subst ?, ,$1)
+notdirx = $(call ?s,$(notdir $(call s?,$1)))
+
+DEVICE = EFM32GG990F1024
+PROJECTNAME = $(call notdirx,$(CURDIR))
+
+OBJ_DIR = build
+EXE_DIR = exe
+LST_DIR = lst
+
+
+####################################################################
+# Definitions of toolchain.                                        #
+# You might need to do changes to match your system setup          #
+####################################################################
+
+RM         := rm -rf
+NULLDEVICE := /dev/null
+SHELLNAMES := $(ComSpec)$(COMSPEC)
+
+# This is only valid for my specific system.
+TOOLCHAIN_BIN_DIR := /opt/simplicitystudio5/developer/toolchains/gnu_arm/10.2_2020q4/bin
+
+CC         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-gcc
+LD         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-ld
+AR         := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-ar
+OBJCOPY    := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-objcopy
+DUMP       := $(TOOLCHAIN_BIN_DIR)/arm-none-eabi-objdump
+
+# Detect operating system
+ifeq ($(SHELLNAMES),)           # Linux
+  EACOM = /opt/simplicitystudio5/developer/adapter_packs/commander/commander
+else
+  EACOM = C:\SiliconLabs\SimplicityStudio\v3\bgtool\commander\commander.exe
+  ifneq ($(COMSPEC),)           # mingw/msys/cygwin platform running on Windows
+    ifeq ($(findstring cygdrive,$(shell set)),)
+      # We were not on a cygwin platform
+      NULLDEVICE := NUL
+    endif
+  else                          # Windows
+    NULLDEVICE := NUL
+  endif
+endif
+
+# Create directories and do a clean which is compatible with parallell make
+$(shell mkdir $(OBJ_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(EXE_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(LST_DIR)>$(NULLDEVICE) 2>&1)
+ifeq (clean,$(findstring clean, $(MAKECMDGOALS)))
+  ifneq ($(filter $(MAKECMDGOALS),all debug release),)
+    $(shell $(RM) $(OBJ_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(EXE_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(LST_DIR)/*>$(NULLDEVICE) 2>&1) #*/
+  endif
+endif
+
+####################################################################
+# Flags                                                            #
+####################################################################
+
+# -MMD : Don't generate dependencies on system header files.
+# -MP  : Add phony targets, useful when a h-file is removed from a project.
+# -MF  : Specify a file to write the dependencies to.
+DEPFLAGS = -MMD -MP -MF $(@:.o=.d)
+
+#
+# Add -Wa,-ahld=$(LST_DIR)/$(@F:.o=.lst) to CFLAGS to produce assembly list files
+#
+override CFLAGS += -D$(DEVICE) -Wall -Wextra -mcpu=cortex-m3 -mthumb -ffunction-sections \
+-fdata-sections -mfix-cortex-m3-ldrd -fomit-frame-pointer -DDEBUG_EFM       \
+-O0 \
+$(DEPFLAGS)
+
+ASMFLAGS += -x assembler-with-cpp -mcpu=cortex-m3 -mthumb
+
+#
+# NOTE: The -Wl,--gc-sections flag may interfere with debugging using gdb.
+#
+override LDFLAGS += -Xlinker -Map=$(LST_DIR)/$(PROJECTNAME).map -mcpu=cortex-m3 \
+-mthumb -Tefm32gg.ld --specs=nano.specs \
+ -Wl,--gc-sections
+
+LIBS = -Wl,--start-group -lgcc -lc -lnosys -Wl,--end-group
+
+INCLUDEPATHS += \
+-I.. \
+-I../common/CMSIS/Include \
+-I../common/EFM32GG/Include \
+-I../common/emlib/inc \
+-I../common/EFM32/drivers \
+-I../common/EFM32/bsp \
+-I../common/EFM32GG_STK3700/config
+
+####################################################################
+# Files                                                            #
+####################################################################
+
+C_SRC +=  \
+../common/EFM32GG/Source/system_efm32gg.c \
+../common/EFM32/drivers/vddcheck.c \
+../common/EFM32/drivers/segmentlcd.c \
+../common/emlib/src/em_assert.c \
+../common/emlib/src/em_cmu.c \
+../common/emlib/src/em_emu.c \
+../common/emlib/src/em_gpio.c \
+../common/emlib/src/em_rtc.c \
+../common/emlib/src/em_system.c \
+../common/emlib/src/em_lcd.c \
+../common/emlib/src/em_vcmp.c \
+../common/emlib/src/em_usart.c \
+../common/EFM32/bsp/bsp_stk.c \
+../common/EFM32/bsp/bsp_stk_leds.c \
+../common/EFM32/bsp/bsp_trace.c \
+../common/$(PROJECTNAME)/init.c
+
+s_SRC +=  \
+../common/EFM32GG/Source/GCC/startup_efm32gg.s
+
+STUDENT_SRC += \
+$(PROJECTNAME).s
+# gpio_constants.s \
+# sys-tick_constants.s
+
+####################################################################
+# Rules                                                            #
+####################################################################
+
+C_FILES = $(notdir $(C_SRC) )
+S_FILES = $(notdir $(S_SRC) $(s_SRC) )
+#make list of source paths, sort also removes duplicates
+C_PATHS = $(sort $(dir $(C_SRC) ) )
+S_PATHS = $(sort $(dir $(S_SRC) $(s_SRC) ) )
+
+C_OBJS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.o))
+S_OBJS = $(if $(S_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.S=.o)))
+s_OBJS = $(if $(s_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.s=.o)))
+C_DEPS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.d))
+OBJS = $(C_OBJS) $(S_OBJS) $(s_OBJS)
+STUDENT_OBJS = $(addprefix $(OBJ_DIR)/, $(STUDENT_SRC:.s=.o))
+
+vpath %.c $(C_PATHS)
+vpath %.s $(S_PATHS)
+vpath %.S $(S_PATHS)
+
+
+# Default build is debug build
+all:      debug
+
+debug:    CFLAGS += -DDEBUG -O0 -g3
+debug:    $(EXE_DIR)/$(PROJECTNAME).bin
+
+release:  CFLAGS += -DNDEBUG -O3 -g3 
+release:  $(EXE_DIR)/$(PROJECTNAME).bin
+
+rammeverk:  $(OBJS)
+
+# Create objects from C SRC files
+$(OBJ_DIR)/%.o: %.c
+	@echo "Building file: $<"
+	$(CC) $(CFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Assemble .s/.S files
+$(OBJ_DIR)/%.o: %.s
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+$(OBJ_DIR)/%.o: %.S
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Link
+$(EXE_DIR)/$(PROJECTNAME).out: $(STUDENT_OBJS) 
+	@echo "Linking target: $@"
+	$(CC) $(LDFLAGS) $(OBJS) $(STUDENT_OBJS) $(LIBS) -o $(EXE_DIR)/$(PROJECTNAME).out
+
+# Create binary file
+$(EXE_DIR)/$(PROJECTNAME).bin: $(EXE_DIR)/$(PROJECTNAME).out
+	@echo "Creating binary file"
+	$(OBJCOPY) -O binary $(EXE_DIR)/$(PROJECTNAME).out $(EXE_DIR)/$(PROJECTNAME).bin
+# Uncomment next line to produce assembly listing of entire program
+#	$(DUMP) -h -S -C $(EXE_DIR)/$(PROJECTNAME).out>$(LST_DIR)/$(PROJECTNAME)out.lst
+
+# Flash on!
+ifeq ($(f), 1)
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+endif
+
+clean:
+ifeq ($(filter $(MAKECMDGOALS),all debug release),)
+	$(RM) $(LST_DIR) $(EXE_DIR)
+	$(RM) $(STUDENT_OBJS)
+endif
+
+# include auto-generated dependency files (explicit rules)
+ifneq (clean,$(findstring clean, $(MAKECMDGOALS)))
+-include $(C_DEPS)
+endif
+
+flash:
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+	@echo "Completed!"
--- a/o3/Makefile.original
+++ b/o3/Makefile.original
@ -0,0 +1,212 @@
+####################################################################
+# Makefile                                                         #
+####################################################################
+
+.SUFFIXES:				# ignore builtin rules
+.PHONY: all debug release clean flash rammeverk 
+
+####################################################################
+# Definitions                                                      #
+####################################################################
+
+# notdirx: version of notdir which allows spaces in path
+s? = $(subst $(empty) ,?,$1)
+?s = $(subst ?, ,$1)
+notdirx = $(call ?s,$(notdir $(call s?,$1)))
+
+DEVICE = EFM32GG990F1024
+PROJECTNAME = $(call notdirx,$(CURDIR))
+
+OBJ_DIR = build
+EXE_DIR = exe
+LST_DIR = lst
+
+
+####################################################################
+# Definitions of toolchain.                                        #
+# You might need to do changes to match your system setup          #
+####################################################################
+
+RM         := rm -rf
+NULLDEVICE := /dev/null
+SHELLNAMES := $(ComSpec)$(COMSPEC)
+
+CC         := arm-none-eabi-gcc
+LD         := arm-none-eabi-ld
+AR         := arm-none-eabi-ar
+OBJCOPY    := arm-none-eabi-objcopy
+DUMP       := arm-none-eabi-objdump
+
+# Detect operating system
+ifeq ($(SHELLNAMES),)           # Linux
+  EACOM = /opt/SimplicityStudio_v3/bgtool/commander/commander
+else
+  EACOM = C:\SiliconLabs\SimplicityStudio\v3\bgtool\commander\commander.exe
+  ifneq ($(COMSPEC),)           # mingw/msys/cygwin platform running on Windows
+    ifeq ($(findstring cygdrive,$(shell set)),)
+      # We were not on a cygwin platform
+      NULLDEVICE := NUL
+    endif
+  else                          # Windows
+    NULLDEVICE := NUL
+  endif
+endif
+
+# Create directories and do a clean which is compatible with parallell make
+$(shell mkdir $(OBJ_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(EXE_DIR)>$(NULLDEVICE) 2>&1)
+$(shell mkdir $(LST_DIR)>$(NULLDEVICE) 2>&1)
+ifeq (clean,$(findstring clean, $(MAKECMDGOALS)))
+  ifneq ($(filter $(MAKECMDGOALS),all debug release),)
+    $(shell $(RM) $(OBJ_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(EXE_DIR)/*>$(NULLDEVICE) 2>&1)
+    $(shell $(RM) $(LST_DIR)/*>$(NULLDEVICE) 2>&1) #*/
+  endif
+endif
+
+
+
+
+####################################################################
+# Flags                                                            #
+####################################################################
+
+# -MMD : Don't generate dependencies on system header files.
+# -MP  : Add phony targets, useful when a h-file is removed from a project.
+# -MF  : Specify a file to write the dependencies to.
+DEPFLAGS = -MMD -MP -MF $(@:.o=.d)
+
+#
+# Add -Wa,-ahld=$(LST_DIR)/$(@F:.o=.lst) to CFLAGS to produce assembly list files
+#
+override CFLAGS += -D$(DEVICE) -Wall -Wextra -mcpu=cortex-m3 -mthumb -ffunction-sections \
+-fdata-sections -mfix-cortex-m3-ldrd -fomit-frame-pointer -DDEBUG_EFM       \
+-O0 \
+$(DEPFLAGS)
+
+ASMFLAGS += -x assembler-with-cpp -mcpu=cortex-m3 -mthumb
+
+#
+# NOTE: The -Wl,--gc-sections flag may interfere with debugging using gdb.
+#
+override LDFLAGS += -Xlinker -Map=$(LST_DIR)/$(PROJECTNAME).map -mcpu=cortex-m3 \
+-mthumb -Tefm32gg.ld --specs=nano.specs \
+ -Wl,--gc-sections
+
+LIBS = -Wl,--start-group -lgcc -lc -lnosys -Wl,--end-group
+
+INCLUDEPATHS += \
+-I.. \
+-I../common/CMSIS/Include \
+-I../common/EFM32GG/Include \
+-I../common/emlib/inc \
+-I../common/EFM32/drivers \
+-I../common/EFM32/bsp \
+-I../common/EFM32GG_STK3700/config
+
+####################################################################
+# Files                                                            #
+####################################################################
+
+C_SRC +=  \
+../common/EFM32GG/Source/system_efm32gg.c \
+../common/EFM32/drivers/vddcheck.c \
+../common/EFM32/drivers/segmentlcd.c \
+../common/emlib/src/em_assert.c \
+../common/emlib/src/em_cmu.c \
+../common/emlib/src/em_emu.c \
+../common/emlib/src/em_gpio.c \
+../common/emlib/src/em_rtc.c \
+../common/emlib/src/em_system.c \
+../common/emlib/src/em_lcd.c \
+../common/emlib/src/em_vcmp.c \
+../common/emlib/src/em_usart.c \
+../common/EFM32/bsp/bsp_stk.c \
+../common/EFM32/bsp/bsp_stk_leds.c \
+../common/EFM32/bsp/bsp_trace.c \
+../common/$(PROJECTNAME)/init.c
+
+s_SRC +=  \
+../common/EFM32GG/Source/GCC/startup_efm32gg.s
+
+STUDENT_SRC += \
+$(PROJECTNAME).c
+
+####################################################################
+# Rules                                                            #
+####################################################################
+
+C_FILES = $(notdir $(C_SRC) )
+S_FILES = $(notdir $(S_SRC) $(s_SRC) )
+#make list of source paths, sort also removes duplicates
+C_PATHS = $(sort $(dir $(C_SRC) ) )
+S_PATHS = $(sort $(dir $(S_SRC) $(s_SRC) ) )
+
+C_OBJS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.o))
+S_OBJS = $(if $(S_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.S=.o)))
+s_OBJS = $(if $(s_SRC), $(addprefix $(OBJ_DIR)/, $(S_FILES:.s=.o)))
+C_DEPS = $(addprefix $(OBJ_DIR)/, $(C_FILES:.c=.d))
+OBJS = $(C_OBJS) $(S_OBJS) $(s_OBJS)
+STUDENT_OBJS = $(addprefix $(OBJ_DIR)/, $(STUDENT_SRC:.c=.o))
+
+vpath %.c $(C_PATHS)
+vpath %.s $(S_PATHS)
+vpath %.S $(S_PATHS)
+
+
+# Default build is debug build
+all:      debug
+
+debug:    CFLAGS += -DDEBUG -O0 -g3
+debug:    $(EXE_DIR)/$(PROJECTNAME).bin
+
+release:  CFLAGS += -DNDEBUG -O3 -g3 
+release:  $(EXE_DIR)/$(PROJECTNAME).bin
+
+rammeverk:  $(OBJS)
+
+# Create objects from C SRC files
+$(OBJ_DIR)/%.o: %.c
+	@echo "Building file: $<"
+	$(CC) $(CFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Assemble .s/.S files
+$(OBJ_DIR)/%.o: %.s
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+$(OBJ_DIR)/%.o: %.S
+	@echo "Assembling $<"
+	$(CC) $(ASMFLAGS) $(INCLUDEPATHS) -c -o $@ $<
+
+# Link
+$(EXE_DIR)/$(PROJECTNAME).out: $(STUDENT_OBJS) 
+	@echo "Linking target: $@"
+	$(CC) $(LDFLAGS) $(OBJS) $(STUDENT_OBJS) $(LIBS) -o $(EXE_DIR)/$(PROJECTNAME).out
+
+# Create binary file
+$(EXE_DIR)/$(PROJECTNAME).bin: $(EXE_DIR)/$(PROJECTNAME).out
+	@echo "Creating binary file"
+	$(OBJCOPY) -O binary $(EXE_DIR)/$(PROJECTNAME).out $(EXE_DIR)/$(PROJECTNAME).bin
+# Uncomment next line to produce assembly listing of entire program
+#	$(DUMP) -h -S -C $(EXE_DIR)/$(PROJECTNAME).out>$(LST_DIR)/$(PROJECTNAME)out.lst
+
+# Flash on!
+ifeq ($(f), 1)
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+endif
+
+clean:
+ifeq ($(filter $(MAKECMDGOALS),all debug release),)
+	$(RM) $(LST_DIR) $(EXE_DIR)
+	$(RM) $(STUDENT_OBJS)
+endif
+
+# include auto-generated dependency files (explicit rules)
+ifneq (clean,$(findstring clean, $(MAKECMDGOALS)))
+-include $(C_DEPS)
+endif
+
+flash:
+	$(EACOM) flash $(EXE_DIR)/$(PROJECTNAME).bin
+	@echo "Completed!"
--- a/o3/efm32gg.ld
+++ b/o3/efm32gg.ld
@ -0,0 +1,207 @@
+/* Linker script for Silicon Labs EFM32GG devices                      */
+/*                                                                     */
+/* This file is subject to the license terms as defined in ARM's       */
+/* CMSIS END USER LICENSE AGREEMENT.pdf, governing the use of          */
+/* Example Code.                                                       */
+/*                                                                     */
+/* Copyright 2018 Silicon Laboratories, Inc. http://www.silabs.com     */
+/*                                                                     */
+/* Version 5.5.0 */
+/*                                                                     */
+
+MEMORY
+{
+  FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 1048576
+  RAM (rwx)  : ORIGIN = 0x20000000, LENGTH = 131072
+}
+
+/* Linker script to place sections and symbol values. Should be used together
+ * with other linker script that defines memory regions FLASH and RAM.
+ * It references following symbols, which must be defined in code:
+ *   Reset_Handler : Entry of reset handler
+ *
+ * It defines following symbols, which code can use without definition:
+ *   __exidx_start
+ *   __exidx_end
+ *   __copy_table_start__
+ *   __copy_table_end__
+ *   __zero_table_start__
+ *   __zero_table_end__
+ *   __etext
+ *   __data_start__
+ *   __preinit_array_start
+ *   __preinit_array_end
+ *   __init_array_start
+ *   __init_array_end
+ *   __fini_array_start
+ *   __fini_array_end
+ *   __data_end__
+ *   __bss_start__
+ *   __bss_end__
+ *   __end__
+ *   end
+ *   __HeapLimit
+ *   __StackLimit
+ *   __StackTop
+ *   __stack
+ *   __Vectors_End
+ *   __Vectors_Size
+ */
+ENTRY(Reset_Handler)
+
+SECTIONS
+{
+  .text :
+  {
+    KEEP(*(.vectors))
+    __Vectors_End = .;
+    __Vectors_Size = __Vectors_End - __Vectors;
+    __end__ = .;
+
+    *(.text*)
+
+    KEEP(*(.init))
+    KEEP(*(.fini))
+
+    /* .ctors */
+    *crtbegin.o(.ctors)
+    *crtbegin?.o(.ctors)
+    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
+    *(SORT(.ctors.*))
+    *(.ctors)
+
+    /* .dtors */
+    *crtbegin.o(.dtors)
+    *crtbegin?.o(.dtors)
+    *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
+    *(SORT(.dtors.*))
+    *(.dtors)
+
+    *(.rodata*)
+
+    KEEP(*(.eh_frame*))
+  } > FLASH
+
+  .ARM.extab :
+  {
+    *(.ARM.extab* .gnu.linkonce.armextab.*)
+  } > FLASH
+
+  __exidx_start = .;
+  .ARM.exidx :
+  {
+    *(.ARM.exidx* .gnu.linkonce.armexidx.*)
+  } > FLASH
+  __exidx_end = .;
+
+  /* To copy multiple ROM to RAM sections,
+   * uncomment .copy.table section and,
+   * define __STARTUP_COPY_MULTIPLE in startup_ARMCMx.S */
+  /*
+  .copy.table :
+  {
+    . = ALIGN(4);
+    __copy_table_start__ = .;
+    LONG (__etext)
+    LONG (__data_start__)
+    LONG (__data_end__ - __data_start__)
+    LONG (__etext2)
+    LONG (__data2_start__)
+    LONG (__data2_end__ - __data2_start__)
+    __copy_table_end__ = .;
+  } > FLASH
+  */
+
+  /* To clear multiple BSS sections,
+   * uncomment .zero.table section and,
+   * define __STARTUP_CLEAR_BSS_MULTIPLE in startup_ARMCMx.S */
+  /*
+  .zero.table :
+  {
+    . = ALIGN(4);
+    __zero_table_start__ = .;
+    LONG (__bss_start__)
+    LONG (__bss_end__ - __bss_start__)
+    LONG (__bss2_start__)
+    LONG (__bss2_end__ - __bss2_start__)
+    __zero_table_end__ = .;
+  } > FLASH
+  */
+
+  __etext = .;
+
+  .data : AT (__etext)
+  {
+    __data_start__ = .;
+    *(vtable)
+    *(.data*)
+    . = ALIGN (4);
+    *(.ram)
+
+    . = ALIGN(4);
+    /* preinit data */
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP(*(.preinit_array))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+
+    . = ALIGN(4);
+    /* init data */
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP(*(SORT(.init_array.*)))
+    KEEP(*(.init_array))
+    PROVIDE_HIDDEN (__init_array_end = .);
+
+    . = ALIGN(4);
+    /* finit data */
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP(*(SORT(.fini_array.*)))
+    KEEP(*(.fini_array))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+
+    KEEP(*(.jcr*))
+    . = ALIGN(4);
+    /* All data end */
+    __data_end__ = .;
+
+  } > RAM
+
+  .bss :
+  {
+    . = ALIGN(4);
+    __bss_start__ = .;
+    *(.bss*)
+    *(COMMON)
+    . = ALIGN(4);
+    __bss_end__ = .;
+  } > RAM
+
+  .heap (COPY):
+  {
+    __HeapBase = .;
+    __end__ = .;
+    end = __end__;
+    _end = __end__;
+    KEEP(*(.heap*))
+    __HeapLimit = .;
+  } > RAM
+
+  /* .stack_dummy section doesn't contains any symbols. It is only
+   * used for linker to calculate size of stack sections, and assign
+   * values to stack symbols later */
+  .stack_dummy (COPY):
+  {
+    KEEP(*(.stack*))
+  } > RAM
+
+  /* Set stack top to end of RAM, and stack limit move down by
+   * size of stack_dummy section */
+  __StackTop = ORIGIN(RAM) + LENGTH(RAM);
+  __StackLimit = __StackTop - SIZEOF(.stack_dummy);
+  PROVIDE(__stack = __StackTop);
+
+  /* Check if data + heap + stack exceeds RAM limit */
+  ASSERT(__StackLimit >= __HeapLimit, "region RAM overflowed with stack")
+
+  /* Check if FLASH usage exceeds FLASH size */
+  ASSERT( LENGTH(FLASH) >= (__etext + SIZEOF(.data)), "FLASH memory overflowed !")
+}
--- a/o3/gpio.h
+++ b/o3/gpio.h
@ -0,0 +1,26 @@
+#ifndef GPIO_H
+#define GPIO_H
+
+// Pin-datatype
+typedef struct{
+	unsigned int   port;
+	unsigned int   pin;
+} port_pin_t;
+
+// GPIO pin modes
+#define GPIO_MODE_INPUT  0b0001
+#define GPIO_MODE_OUTPUT 0b0100
+
+// GPIO-adresse
+#define GPIO_BASE 0x40006000
+
+// GPIO port-nummere
+#define GPIO_PORT_A 0
+#define GPIO_PORT_B 1
+#define GPIO_PORT_C 2
+#define GPIO_PORT_D 3
+#define GPIO_PORT_E 4
+#define GPIO_PORT_F 5
+
+
+#endif
--- a/o3/o3.c
+++ b/o3/o3.c
@ -0,0 +1,252 @@
+#include "o3.h"
+#include "gpio.h"
+#include "systick.h"
+
+/**************************************************************************/ /**
+ * @brief Konverterer nummer til string 
+ * Konverterer et nummer mellom 0 og 99 til string
+ *****************************************************************************/
+void int_to_string(char *timestamp, unsigned int offset, int i)
+{
+  if (i > 99)
+  {
+    timestamp[offset] = '9';
+    timestamp[offset + 1] = '9';
+    return;
+  }
+
+  while (i > 0)
+  {
+    if (i >= 10)
+    {
+      i -= 10;
+      timestamp[offset]++;
+    }
+    else
+    {
+      timestamp[offset + 1] = '0' + i;
+      i = 0;
+    }
+  }
+}
+
+/**************************************************************************/ /**
+ * @brief Konverterer 3 tall til en timestamp-string
+ * timestamp-argumentet må være et array med plass til (minst) 7 elementer.
+ * Det kan deklareres i funksjonen som kaller som "char timestamp[7];"
+ * Kallet blir dermed:
+ * char timestamp[7];
+ * time_to_string(timestamp, h, m, s);
+ *****************************************************************************/
+void time_to_string(char *timestamp, int h, int m, int s)
+{
+  timestamp[0] = '0';
+  timestamp[1] = '0';
+  timestamp[2] = '0';
+  timestamp[3] = '0';
+  timestamp[4] = '0';
+  timestamp[5] = '0';
+  timestamp[6] = '\0';
+
+  int_to_string(timestamp, 0, h);
+  int_to_string(timestamp, 2, m);
+  int_to_string(timestamp, 4, s);
+}
+
+/* -------------------------------------------------------------------------- */
+
+typedef struct {
+  word CTRL;
+  word MODEL;
+  word MODEH;
+  word DOUT;
+  word DOUTSET;
+  word DOUTCLR;
+  word DOUTTGL;
+  word DIN;
+  word PINLOCKN;
+} gpio_port_map_t;
+
+typedef volatile struct {
+   gpio_port_map_t ports[6];
+   word unused_space[10];
+   word EXTIPSELL;
+   word EXTIPSELH;
+   word EXTIRISE;
+   word EXTIFALL;
+   word IEN;
+   word IF;
+   word IFS;
+   word IFC;
+   word ROUTE;
+   word INSENSE;
+   word LOCK;
+   word CTRL;
+   word CMD;
+   word EM4WUEN;
+   word EM4WUPOL;
+   word EM4WUCAUSE;
+} gpio_t;
+
+typedef volatile struct {
+  word CTRL;
+  word LOAD;
+  word VAL;
+  word CALIB;
+} systick_t;
+
+static volatile gpio_t* const gpio = (gpio_t*) GPIO_BASE;
+static volatile systick_t* const systick = (systick_t*) SYSTICK_BASE;
+
+#define GPIO_LED GPIO_PORT_E
+#define GPIO_PB GPIO_PORT_B
+#define LED_PIN 2
+#define PB0_PIN 9
+#define PB1_PIN 10
+
+/* -------------------------------------------------------------------------- */
+
+enum PROGRAM_STATE {
+  ADD_SECS,
+  ADD_MINS,
+  ADD_HOURS,
+  COUNTDOWN,
+  ALARM,
+  PROGRAM_STATE_SIZE,
+};
+
+static struct {
+  char display[7];
+  unsigned char hours;
+  unsigned char minutes;
+  unsigned char seconds;
+  unsigned char programState;
+} state;
+
+void initializeState() {
+  state.hours = 0;
+  state.minutes = 0;
+  state.seconds = 0;
+  state.programState = ADD_SECS;
+}
+
+void initializeInterruptHandlers()
+{
+  // Setup SYSTICK
+  systick->CTRL = 0b111;
+  systick->LOAD = FREQUENCY;
+  systick->VAL  = 1;
+
+  // Setup LED
+  volatile word* setting;
+  setting = &gpio->ports[GPIO_LED].MODEL;
+  *setting &= ~(0xF << (4 * LED_PIN));
+  *setting += GPIO_MODE_OUTPUT << (4 * LED_PIN);
+
+  // Setup buttons
+  for (char i=0; i<2; i++) {
+    setting = i ? &gpio->ports[GPIO_PB].MODEH : &gpio->EXTIPSELH;
+    *setting &= ~(0xFF << 4);
+    *setting += 0x110;
+
+    word button = i ? PB0_PIN : PB1_PIN;
+    gpio->EXTIFALL |= (1 << button);
+    gpio->IEN      |= (1 << button);
+  }
+}
+
+void activateAlarm()
+{
+  state.programState = ALARM;
+  gpio->ports[GPIO_LED].DOUTSET = 1 << LED_PIN;
+}
+
+void deactivateAlarm()
+{
+    gpio->ports[GPIO_LED].DOUTCLR = 1 << LED_PIN;
+}
+
+void turnToNextState()
+{
+  if (state.programState == COUNTDOWN) return;
+  if (state.programState == ALARM) 
+    deactivateAlarm();
+
+  state.programState++;
+  state.programState %= PROGRAM_STATE_SIZE;
+}
+
+void updateScreen()
+{
+  time_to_string(state.display, state.hours, state.minutes, state.seconds);
+  lcd_write(state.display);
+}
+
+/* -------------------------------------------------------------------------- */
+
+void SysTick_Handler()
+{
+  gpio->ports[GPIO_LED].DOUTTGL = 1;
+  if (state.programState != COUNTDOWN) return;
+
+  if (!state.seconds) {
+    if (!state.minutes) {
+      if (!state.hours) {
+        activateAlarm();
+        return;
+      }
+      state.hours--;
+      state.minutes = 60;
+      return;
+    }
+    state.minutes--;
+    state.seconds = 60;
+    return;
+  }
+  state.seconds--;
+}
+
+// PB0
+void GPIO_ODD_IRQHandler()
+{
+  switch (state.programState)
+  {
+    case ADD_SECS:
+      state.seconds++;
+      state.seconds %= 60;
+      break;
+
+    case ADD_MINS:
+      state.minutes++;
+      state.minutes %= 60;
+      break;
+
+    case ADD_HOURS:
+      state.hours++;
+      break;
+  }
+  gpio->IFC = 1 << PB0_PIN;
+}
+
+// PB1
+void GPIO_EVEN_IRQHandler()
+{
+  turnToNextState();
+  gpio->IFC = 1 << PB1_PIN;
+}
+
+/* -------------------------------------------------------------------------- */
+
+int main(void)
+{
+  init();
+  initializeInterruptHandlers();
+  initializeState();
+
+  for (;;) {
+    updateScreen();
+    __asm__("WFI");
+  }
+
+  return 0;
+}
--- a/o3/o3.h
+++ b/o3/o3.h
@ -0,0 +1,30 @@
+/* En rask måte å unngå header recursion på er å sjekke om verdi, f.eks. 'O3_H',
+   er definert. Hvis ikke, definer 'O3_H' og deretter innholdet av headeren 
+   (merk endif på bunnen). Nå kan headeren inkluderes så mange ganger vi vil 
+   uten at det blir noen problemer. */
+#ifndef O3_H
+#define O3_H
+
+// Type-definisjoner fra std-bibliotekene
+#include <stdint.h>
+#include <stdbool.h>
+
+// Type-aliaser
+typedef uint32_t word;
+typedef uint8_t  byte;
+
+// Prototyper for bibliotekfunksjoner
+void init(void);
+void lcd_write(char* string);
+void int_to_string(char *timestamp, unsigned int offset, int i);
+void time_to_string(char *timestamp, int h, int m, int s);
+
+// Prototyper
+// legg prototyper for dine funksjoner her
+
+void initializeInterruptHandlers();
+void SysTick_Handler();
+void GPIO_ODD_IRQHandler();
+void GPIO_EVEN_IRQHandler();
+
+#endif
--- a/o3/systick.h
+++ b/o3/systick.h
@ -0,0 +1,15 @@
+#ifndef SYSTICK_H
+#define SYSTICK_H
+
+// Sys-Tick adresse
+#define SYSTICK_BASE 0xE000E010
+
+// Antall klokkesignaler per sekund
+#define FREQUENCY 14000000 
+
+// CTRL-register-masker
+#define SysTick_CTRL_CLKSOURCE_Msk  0b100
+#define SysTick_CTRL_TICKINT_Msk    0b010
+#define SysTick_CTRL_ENABLE_Msk     0b001
+
+#endif
--- a/o456.pdf
+++ b/o456.pdf
--- a/o456/o4.md
+++ b/o456/o4.md
@ -0,0 +1,20 @@
+
+```
+ldi   %r2,  1
+00000 00010 0000000000000000000001
+
+ldi %r1, 1
+00000 00001 0000000000000000000001
+
+mul   %r2,  %r2,  %r0
+00010 00010 00010 00000 XXXXXXXXXXXX
+
+sub   %r0,  %r0,  %r1
+00101 00000 00000 00001 XXXXXXXXXXXX
+
+cmp   %r3,  %r0,  %r1
+00011 00011 00000 00001 XXXXXXXXXXXX
+
+jgt   %r3,  -16
+00100 00011 1111111111111111110000
+```
--- a/o456/o4.txt
+++ b/o456/o4.txt
@ -0,0 +1,6 @@
+00000000100000000000000000000001
+00000000010000000000000000000001
+00010000100001000000XXXXXXXXXXXX
+00101000000000000001XXXXXXXXXXXX
+00011000110000000001XXXXXXXXXXXX
+00100000111111111111111111110000
--- a/o456/o5.c
+++ b/o456/o5.c
@ -0,0 +1,22 @@
+#include <stdio.h>
+
+
+int f(int r0) {
+	int r2 = 1;
+	int r1 = 1;
+back16:
+	r2 = r2 * r0;
+	r0 = r0 - r1;
+	if (r0 > r1) {
+		goto back16;
+	}
+	return r2;
+}
+
+int main() {
+	int vals[] = {2, 3, 4, 9};
+	for (int i=0; i<4; i++) {
+		printf("f( r0=%d ) = %d\n", vals[i], f(vals[i]));
+	}
+	return 0;
+}
--- a/o456/o5.txt
+++ b/o456/o5.txt
@ -0,0 +1,4 @@
+2
+6
+24
+362880
--- a/o456/o6.py
+++ b/o456/o6.py
@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+from dataclasses import dataclass
+
+xs = []
+
+@dataclass
+class Regs:
+  imm: int
+  alu: int
+  regw: int
+  branch: int
+
+  def __str__(self):
+    return f'{self.imm}{self.alu}{self.regw}{self.branch}'
+
+
+def add():
+  xs.append(Regs(imm=0, alu=0, regw=1, branch=0))
+def sub():
+  xs.append(Regs(imm=0, alu=5, regw=1, branch=0))
+def mul():
+  xs.append(Regs(imm=0, alu=4, regw=1, branch=0))
+def cmp():
+  xs.append(Regs(imm=0, alu=1, regw=1, branch=0))
+def jgt():
+  xs.append(Regs(imm=0, alu=2, regw=0, branch=1))
+def ldi():
+  xs.append(Regs(imm=1, alu=3, regw=1, branch=0))
+
+
+def main():
+  r0 = 1
+  r2 = 1
+  ldi()
+  r1 = 1
+  ldi()
+  while (True):
+    mul()
+    r2 = r2 * r0
+    sub()
+    r0 = r0 - r1
+    cmp()
+    jgt()
+    if not (r0 > r1):
+      break
+
+if __name__ == '__main__':
+  main()
+  for x in xs:
+    print(x)
--- a/o456/o6.txt
+++ b/o456/o6.txt
@ -0,0 +1,6 @@
+1310
+1310
+0410
+0510
+0110
+0201