litex/milkymist/framebuffer/lib.py

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2013-05-22 11:10:13 -04:00
from migen.fhdl.std import *
from migen.genlib.record import Record
from migen.genlib.fifo import AsyncFIFO
from migen.flow.actor import *
from migen.flow.network import *
from migen.flow.transactions import *
from migen.bank.description import CSRStorage
from migen.actorlib import spi
_hbits = 11
_vbits = 12
bpp = 32
bpc = 10
pixel_layout_s = [
("pad", bpp-3*bpc),
("r", bpc),
("g", bpc),
("b", bpc)
]
pixel_layout = [
("p0", pixel_layout_s),
("p1", pixel_layout_s)
]
bpc_dac = 8
dac_layout_s = [
("r", bpc_dac),
("g", bpc_dac),
("b", bpc_dac)
]
dac_layout = [
("hsync", 1),
("vsync", 1),
("p0", dac_layout_s),
("p1", dac_layout_s)
]
class FrameInitiator(spi.SingleGenerator):
def __init__(self):
layout = [
("hres", _hbits, 640, 1),
("hsync_start", _hbits, 656, 1),
("hsync_end", _hbits, 752, 1),
("hscan", _hbits, 800, 1),
("vres", _vbits, 480),
("vsync_start", _vbits, 492),
("vsync_end", _vbits, 494),
("vscan", _vbits, 525)
]
spi.SingleGenerator.__init__(self, layout, spi.MODE_EXTERNAL)
class VTG(Module):
def __init__(self):
self.timing = Sink([
("hres", _hbits),
("hsync_start", _hbits),
("hsync_end", _hbits),
("hscan", _hbits),
("vres", _vbits),
("vsync_start", _vbits),
("vsync_end", _vbits),
("vscan", _vbits)])
self.pixels = Sink(pixel_layout)
self.dac = Source(dac_layout)
self.busy = Signal()
hactive = Signal()
vactive = Signal()
active = Signal()
generate_en = Signal()
hcounter = Signal(_hbits)
vcounter = Signal(_vbits)
skip = bpc - bpc_dac
self.comb += [
active.eq(hactive & vactive),
If(active,
[getattr(getattr(self.dac.payload, p), c).eq(getattr(getattr(self.pixels.payload, p), c)[skip:])
for p in ["p0", "p1"] for c in ["r", "g", "b"]]
),
generate_en.eq(self.timing.stb & (~active | self.pixels.stb)),
self.pixels.ack.eq(self.dac.ack & active),
self.dac.stb.eq(generate_en),
self.busy.eq(generate_en)
]
tp = self.timing.payload
self.sync += [
self.timing.ack.eq(0),
If(generate_en & self.dac.ack,
hcounter.eq(hcounter + 1),
If(hcounter == 0, hactive.eq(1)),
If(hcounter == tp.hres, hactive.eq(0)),
If(hcounter == tp.hsync_start, self.dac.payload.hsync.eq(1)),
If(hcounter == tp.hsync_end, self.dac.payload.hsync.eq(0)),
If(hcounter == tp.hscan,
hcounter.eq(0),
If(vcounter == tp.vscan,
vcounter.eq(0),
self.timing.ack.eq(1)
).Else(
vcounter.eq(vcounter + 1)
)
),
If(vcounter == 0, vactive.eq(1)),
If(vcounter == tp.vres, vactive.eq(0)),
If(vcounter == tp.vsync_start, self.dac.payload.vsync.eq(1)),
If(vcounter == tp.vsync_end, self.dac.payload.vsync.eq(0))
)
]
class FIFO(Module):
def __init__(self):
self.dac = Sink(dac_layout)
self.busy = Signal()
self.vga_hsync_n = Signal()
self.vga_vsync_n = Signal()
self.vga_r = Signal(bpc_dac)
self.vga_g = Signal(bpc_dac)
self.vga_b = Signal(bpc_dac)
###
data_width = 2+2*3*bpc_dac
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fifo = AsyncFIFO(data_width, 512)
self.add_submodule(fifo, {"write": "sys", "read": "vga"})
fifo_in = self.dac.payload
fifo_out = Record(dac_layout)
self.comb += [
self.dac.ack.eq(fifo.writable),
fifo.we.eq(self.dac.stb),
fifo.din.eq(fifo_in.raw_bits()),
fifo_out.raw_bits().eq(fifo.dout),
self.busy.eq(0)
]
pix_parity = Signal()
self.sync.vga += [
pix_parity.eq(~pix_parity),
self.vga_hsync_n.eq(~fifo_out.hsync),
self.vga_vsync_n.eq(~fifo_out.vsync),
If(pix_parity,
self.vga_r.eq(fifo_out.p1.r),
self.vga_g.eq(fifo_out.p1.g),
self.vga_b.eq(fifo_out.p1.b)
).Else(
self.vga_r.eq(fifo_out.p0.r),
self.vga_g.eq(fifo_out.p0.g),
self.vga_b.eq(fifo_out.p0.b)
)
]
self.comb += fifo.re.eq(pix_parity)
def sim_fifo_gen():
while True:
t = Token("dac")
yield t
print("H/V:" + str(t.value["hsync"]) + str(t.value["vsync"])
+ " " + str(t.value["r"]) + " " + str(t.value["g"]) + " " + str(t.value["b"]))