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Implement a simple VGA controller

This commit is contained in:
Peder Bergebakken Sundt 2020-08-15 15:48:17 +02:00
parent aead41b8b6
commit b38296538f
2 changed files with 217 additions and 5 deletions
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185
fpga/modules/vga.dg Normal file
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@ -0,0 +1,185 @@
#!/usr/bin/env -S python3 -m dg
import "/nmigen/cli/main"
import "/nmigen_boards.icebreaker/ICEBreakerPlatform"
import "/nmigen_dg/*"
import "/subprocess"
import "/warnings/warn"
import "../common/pipeline"
import "../resources/pmod"
# total_x = front_x + sync_x + back_x + active_x
# total_y = front_y + sync_y + back_y + active_x
# pix_freq = total_x * total_y * fps
VGA_TIMINGS = dict' # VGA, SVGA, VESA
#(active_x, active_y, fps), (front_x, sync_x, back_x, front_y, sync_y, back_y)
( 640, 480, 60), ( 16, 96, 48, 11, 2, 31) # Martin Hinner
( 640, 480, 72), ( 24, 40, 128, 9, 3, 28) # Martin Hinner
( 640, 480, 75), ( 16, 96, 48, 11, 2, 32) # Martin Hinner
( 640, 480, 85), ( 32, 48, 112, 1, 3, 25) # Martin Hinner
( 640, 1024, 60), ( 24, 56, 124, 1, 3, 38) # Kevin M. Hubbard
( 800, 480, 45), ( 127, 128, 88, 127, 128, 32) # Kevin M. Hubbard (odd)
( 800, 600, 56), ( 32, 128, 128, 1, 4, 14) # Martin Hinner
( 800, 600, 60), ( 40, 128, 88, 1, 4, 23) # Kevin M. Hubbard
( 800, 600, 60), ( 40, 128, 88, 1, 4, 23) # Martin Hinner
( 800, 600, 72), ( 56, 120, 64, 37, 6, 23) # Martin Hinner
( 800, 600, 75), ( 16, 80, 160, 1, 2, 21) # Martin Hinner
( 800, 600, 85), ( 32, 64, 152, 1, 3, 27) # Martin Hinner
( 1024, 768, 60), ( 24, 136, 160, 3, 6, 29) # Kevin M. Hubbard
( 1024, 768, 60), ( 24, 136, 160, 3, 6, 29) # Martin Hinner
( 1024, 768, 70), ( 24, 136, 144, 3, 6, 29) # Martin Hinner
( 1024, 768, 75), ( 16, 96, 176, 1, 3, 28) # Martin Hinner
( 1024, 768, 85), ( 48, 96, 208, 1, 3, 36) # Martin Hinner
( 1280, 1024, 60), ( 48, 112, 248, 1, 3, 38) # Kevin M. Hubbard
# https://projectf.io/posts/video-timings-vga-720p-1080p/
# https://github.com/icebreaker-fpga/icebreaker-examples/blob/master/dvi-12bit/vga_timing.v
# https://reference.digilentinc.com/learn/programmable-logic/tutorials/vga-display-congroller/start
# http://tinyvga.com/vga-timing
# http://martin.hinner.info/vga/timing.html
# https://linux.die.net/man/1/gtf
run_gtf = x y fps ->
out = subprocess.run ["gtf", str x, str y, str fps, "-x"]
capture_output: True
check: True
hr, hss, hse, hfl, vr, vss, vse, vfl = pipeline out.stdout
bytes.decode
str.splitlines
bind map str.strip
bind filter $ x -> x.startswith "Modeline"
head
str.split
bind drop 3
bind take 8
bind map int
# <--------1--------> <--2--> <--3--> <--4-->
# _________
# |-------------------|_______| |_______
#
# R SS SE FL
# 1: visible image
# 2: blank before sync (aka front porch)
# 3: sync pulse
# 4: blank after sync (aka back porch)
# R: Resolution
# SS: Sync Start
# SE: Sync End
# FL: Frame Length
#total_x, active_x, front_x, sync_x, back_x = hfl, hr, hss-hr, hse-hss, hfl-hse
#total_y, active_y, front_y, sync_y, back_y = vfl, vr, vss-vr, vse-vss, vfl-vse
#print hr hss hse hfl
#print vr vss vse vfl
#print active_x front_x sync_x back_x total_x sep:"\t"
#print active_y front_y sync_y back_y total_x sep:"\t"
#return (front_x, sync_x, back_x, front_y, sync_y, back_y)
hss-hr, hse-hss, hfl-hse, vss-vr, vse-vss, vfl-vse
VgaController = subclass Elaboratable where
__init__ = x y fps bitwidth resource_name resource_number: 0 ~> None where
# params
@resource = (resource_name, resource_number)
@active_x, @active_y = x, y
# out
@pixel_x = Signal$ range @active_x
@pixel_y = Signal$ range @active_y
@active = Signal!
# in
@r = Signal$ bitwidth
@g = Signal$ bitwidth
@b = Signal$ bitwidth
# derived params
@front_x, @sync_x, @back_x, @front_y, @sync_y, @back_y = if
(x, y, fps) in VGA_TIMINGS => VGA_TIMINGS!!(x, y, fps)
otherwise => run_gtf x y fps
@total_x = @front_x + @sync_x + @back_x + @active_x
@total_y = @front_y + @sync_y + @back_y + @active_y
@pix_freq = @total_x * @total_y * fps
timings = ~>
"\n".join$ list'
("total_x = " + (str @total_x ) |>.ljust 25) + " total_y = " + (str @total_y )
("front_x = " + (str @front_x ) |>.ljust 25) + " front_y = " + (str @front_y )
("sync_x = " + (str @sync_x ) |>.ljust 25) + " sync_y = " + (str @sync_y )
("back_x = " + (str @back_x ) |>.ljust 25) + " back_y = " + (str @back_y )
("active_x = " + (str @active_x) |>.ljust 25) + " active_y = " + (str @active_y)
("pix_freq = " + (str @pix_freq))
elaborate = platform ~> m where with m = Module! =>
@out = platform.request *: @resource
# pass along the color data
Sync$ @out.r :== @r
Sync$ @out.g :== @g
Sync$ @out.b :== @b
# position counters
counter_x = Signal$ range @total_x
counter_y = Signal$ range @total_y
Sync$ counter_x :== counter_x + 1
When (counter_x == @total_x - 1) $ ->
Sync$ counter_x :== 0
Sync$ counter_y :== counter_y + 1
When (counter_y == @total_y - 1) $ ->
Sync$ counter_y :== 0
# drive vga syncs, data enable and user outputs
Comb$ @pixel_x :== counter_x
Comb$ @pixel_y :== counter_y
Sync$ @out.hs :== (&)
@active_x + @front_x <= counter_x
counter_x < @active_x + @front_x + @sync_x
Sync$ @out.vs :== (&)
@active_y + @front_y <= counter_y
counter_y < @active_y + @front_y + @sync_y
Sync$ @out.de :== (&)
counter_x < @active_x
counter_y < @active_y
Comb$ @out.ck :== ClockSignal "sync"
VgaController3 = bind VgaController
resource_name: "vga_3bit"
bitwidth: 1
VgaController12 = bind VgaController
resource_name: "vga_12bit"
bitwidth: 4
DviController3 = bind VgaController
resource_name: "dvi_3bit"
bitwidth: 1
DviController12 = bind VgaController
resource_name: "dvi_12bit"
bitwidth: 4
if __name__ == "__main__" =>
plat = ICEBreakerPlatform! # TODO: does there exist any mock platform?
plat.add_resources$ pmod.dvi_12bit 0
#design = DviController12 800 480 45
design = DviController12 800 600 60
main design plat ports:
list'
design.pixel_x
design.pixel_y
design.ack
design.r
design.g
design.b

33
fpga/resources/pmod.py
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@ -4,9 +4,7 @@ from functools import partial
__all__ = []
def pmod(func):
__all__.append(func.__name__)
return partial(func,
name = func.__name__,
)
return partial(func, name=func.__name__)
# Icebreaker PMODs
@ -41,3 +39,32 @@ def dip_switch8(number, *, pmod, name = __name__, subsignal_args=(), extras={}):
Subsignal("d8", PinsN("10", dir="i", conn=("pmod", pmod)), *subsignal_args),
**extras,
)]
@pmod
def dvi_3bit(number, *, pmod1=0, pmod2=1, name=__name__, subsignal_args=(), extras={}):
return [Resource(name, number,
Subsignal("r", Pins (" 1", dir="o", conn=("pmod", pmod1)), *subsignal_args), # red
Subsignal("g", Pins (" 2", dir="o", conn=("pmod", pmod1)), *subsignal_args), # green
Subsignal("b", Pins (" 3", dir="o", conn=("pmod", pmod2)), *subsignal_args), # blue
Subsignal("ck", Pins (" 4", dir="o", conn=("pmod", pmod2)), *subsignal_args), # data clock
Subsignal("de", Pins (" 7", dir="o", conn=("pmod", pmod2)), *subsignal_args), # data enable
Subsignal("hs", Pins (" 8", dir="o", conn=("pmod", pmod2)), *subsignal_args), # hsync
Subsignal("vs", Pins (" 9", dir="o", conn=("pmod", pmod2)), *subsignal_args), # vsync
#Subsignal("", Pins ("10", dir="o", conn=("pmod", pmod2)), *subsignal_args),
**extras,
)]
@pmod
def dvi_12bit(number, *, pmod1=0, pmod2=1, name=__name__, subsignal_args=(), extras={}):
return [Resource(name, number,
Subsignal("r", Pins (" 8 7 2 1", dir="o", conn=("pmod", pmod1)), *subsignal_args), # red
Subsignal("g", Pins ("10 9 4 3", dir="o", conn=("pmod", pmod1)), *subsignal_args), # green
Subsignal("b", Pins (" 3 7 8 1", dir="o", conn=("pmod", pmod2)), *subsignal_args), # blue
Subsignal("ck", Pins (" 2", dir="o", conn=("pmod", pmod2)), *subsignal_args), # data clock
Subsignal("de", Pins (" 9", dir="o", conn=("pmod", pmod2)), *subsignal_args), # data enable
Subsignal("hs", PinsN(" 4", dir="o", conn=("pmod", pmod2)), *subsignal_args), # hsync
Subsignal("vs", Pins ("10", dir="o", conn=("pmod", pmod2)), *subsignal_args), # vsync
**extras,
)]