dvisampler: decoding

milkymist/dvisampler/decoding.py

@@ -0,0 +1,57 @@
+from migen.fhdl.structure import *
+from migen.fhdl.module import Module
+
+class _TMDSDecoding(Module):
+	def __init__(self):
+		self.input = Signal(10)
+		self.de = Signal()
+		self.data = Signal(8)
+		self.c = Signal(2)
+
+		###
+
+		self.sync.pix += self.de.eq(1)
+		for i, t in enumerate([0b1101010100, 0b0010101011, 0b0101010100, 0b1010101011]):
+			self.sync.pix += If(self.input == t,
+				self.de.eq(0),
+				self.c.eq(i)
+			)
+		self.sync.pix += self.data[0].eq(self.input[0] ^ self.input[9])
+		for i in range(1, 8):
+			self.sync.pix += self.data[i].eq(self.input[i] ^ self.input[i-1] ^ ~self.input[8])
+
+class Decoding(Module):
+	def __init__(self):
+		self.valid_i = Signal()
+		self.data0 = Signal(10)
+		self.data1 = Signal(10)
+		self.data2 = Signal(10)
+
+		self.valid_o = Signal()
+		self.de = Signal()
+		self.r = Signal(8)
+		self.g = Signal(8)
+		self.b = Signal(8)
+		self.hsync = Signal()
+		self.vsync = Signal()
+
+		###
+
+		self.submodules.decode0 = _TMDSDecoding()
+		self.submodules.decode1 = _TMDSDecoding()
+		self.submodules.decode2 = _TMDSDecoding()
+
+		self.comb += [
+			self.decode0.input.eq(self.data0),
+			self.decode1.input.eq(self.data1),
+			self.decode2.input.eq(self.data2),
+
+			self.de.eq(self.decode0.de),
+			self.r.eq(self.decode2.data),
+			self.g.eq(self.decode1.data),
+			self.b.eq(self.decode0.data),
+			self.hsync.eq(self.decode0.c[0]),
+			self.vsync.eq(self.decode0.c[1])
+		]
+
+		self.sync.pix += self.valid_o.eq(self.valid_i)