dvisampler: add sync polarity detection module (thanks Lars for suggestions)

diff --git a/milkymist/dvisampler/syncpol.py b/milkymist/dvisampler/syncpol.py
new file mode 100644 (file)
index 0000000..2ef752a
--- /dev/null
+++ b/milkymist/dvisampler/syncpol.py
@@ -0,0 +1,49 @@
+from migen.fhdl.structure import *
+from migen.fhdl.module import Module
+from migen.genlib.record import Record
+
+from milkymist.dvisampler.common import channel_layout
+
+class SyncPolarity(Module):
+       def __init__(self):
+               self.valid_i = Signal()
+               self.data_in0 = Record(channel_layout)
+               self.data_in1 = Record(channel_layout)
+               self.data_in2 = Record(channel_layout)
+
+               self.valid_o = Signal()
+               self.de = Signal()
+               self.hsync = Signal()
+               self.vsync = Signal()
+               self.r = Signal(8)
+               self.g = Signal(8)
+               self.b = Signal(8)
+
+               ###
+
+               de = self.data_in0.de
+               de_r = Signal()
+               c = self.data_in0.c
+               c_polarity = Signal(2)
+               c_out = Signal(2)
+
+               self.comb += [
+                       self.de.eq(de_r),
+                       self.hsync.eq(c_out[0]),
+                       self.vsync.eq(c_out[1])
+               ]
+
+               self.sync.pix += [
+                       self.valid_o.eq(self.valid_i),
+                       self.r.eq(self.data_in2.d),
+                       self.g.eq(self.data_in1.d),
+                       self.b.eq(self.data_in0.d),
+
+                       de_r.eq(de),
+                       If(de_r & ~de,
+                               c_polarity.eq(c),
+                               c_out.eq(0)
+                       ).Else(
+                               c_out.eq(c ^ c_polarity)
+                       )
+               ]