dvisampler: add core, EDID support

milkymist/dvisampler/__init__.py

@@ -0,0 +1,18 @@
+from migen.fhdl.structure import *
+from migen.fhdl.module import Module
+from migen.bank.description import *
+
+from milkymist.dvisampler.edid import EDID
+
+class DVISampler(Module, AutoReg):
+	def __init__(self, inversions=""):
+		self.clk = Signal()
+		for datan in "012":
+			name = "data" + str(datan)
+			if datan in inversions:
+				name += "_n"
+			setattr(self, name, Signal(name=name))
+		
+		self.submodules.edid = EDID()
+		self.sda = self.edid.sda
+		self.scl = self.edid.scl

milkymist/dvisampler/edid.py

@@ -0,0 +1,182 @@
+from migen.fhdl.structure import *
+from migen.fhdl.specials import Memory, Tristate
+from migen.fhdl.module import Module
+from migen.genlib.cdc import MultiReg
+from migen.genlib.fsm import FSM
+from migen.genlib.misc import chooser
+from migen.bank.description import AutoReg
+
+_default_edid = [
+	0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x3D, 0x17, 0x20, 0x11, 0x3E, 0x11, 0x00, 0x00,
+	0x01, 0x17, 0x01, 0x03, 0x80, 0x30, 0x1B, 0x78, 0x08, 0x1D, 0xC5, 0xA4, 0x55, 0x54, 0xA0, 0x27,
+	0x0C, 0x50, 0x54, 0x3F, 0xC0, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x88, 0x13, 0x20, 0x3C, 0x30, 0x58, 0x2D, 0x20, 0x58, 0x2C,
+	0x45, 0x00, 0xE0, 0x0E, 0x11, 0x00, 0x00, 0x1E, 0x00, 0x00, 0x00, 0xFC, 0x00, 0x4D, 0x31, 0x20,
+	0x44, 0x56, 0x49, 0x20, 0x6D, 0x69, 0x78, 0x65, 0x72, 0x0A, 0x00, 0x00, 0x00, 0x10, 0x00, 0x32,
+	0x4C, 0x1E, 0x53, 0x11, 0x00, 0x0A, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x10,
+	0x00, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x00, 0x2C,
+]
+
+class EDID(Module, AutoReg):
+	def __init__(self, default=_default_edid):
+		self.scl = Signal()
+		self.sda = Signal()
+
+		self.specials.mem = Memory(8, 128, init=default)
+
+		###
+
+		scl_i = Signal()
+		sda_i = Signal()
+		sda_drv = Signal()
+		_sda_drv_reg = Signal()
+		_sda_i_async = Signal()
+		self.sync += _sda_drv_reg.eq(sda_drv)
+		self.specials += [
+			MultiReg(self.scl, "ext", scl_i, "sys"),
+			Tristate(self.sda, 0, _sda_drv_reg, _sda_i_async),
+			MultiReg(_sda_i_async, "ext", sda_i, "sys")
+		]
+
+		# FIXME: understand what is really going on here and get rid of that workaround
+		for x in range(20):
+			new_scl = Signal()
+			self.sync += new_scl.eq(scl_i)
+			scl_i = new_scl
+		#
+
+		scl_r = Signal()
+		sda_r = Signal()
+		scl_rising = Signal()
+		sda_rising = Signal()
+		sda_falling = Signal()
+		self.sync += [
+			scl_r.eq(scl_i),
+			sda_r.eq(sda_i)
+		]
+		self.comb += [
+			scl_rising.eq(scl_i & ~scl_r),
+			sda_rising.eq(sda_i & ~sda_r),
+			sda_falling.eq(~sda_i & sda_r)
+		]
+
+		start = Signal()
+		self.comb += start.eq(scl_i & sda_falling)
+
+		din = Signal(8)
+		counter = Signal(max=9)
+		self.sync += [
+			If(start, counter.eq(0)),
+			If(scl_rising,
+				If(counter == 8,
+					counter.eq(0)
+				).Else(
+					counter.eq(counter + 1),
+					din.eq(Cat(sda_i, din[:7]))
+				)
+			)
+		]
+
+		is_read = Signal()
+		update_is_read = Signal()
+		self.sync += If(update_is_read, is_read.eq(din[0]))
+
+		offset_counter = Signal(max=128)
+		oc_load = Signal()
+		oc_inc = Signal()
+		self.sync += [
+			If(oc_load,
+				offset_counter.eq(din)
+			).Elif(oc_inc,
+				offset_counter.eq(offset_counter + 1)
+			)
+		]
+		rdport = self.mem.get_port()
+		self.comb += rdport.adr.eq(offset_counter)
+		data_bit = Signal()
+
+		zero_drv = Signal()
+		data_drv = Signal()
+		self.comb += If(zero_drv, sda_drv.eq(1)).Elif(data_drv, sda_drv.eq(~data_bit))
+
+		data_drv_en = Signal()
+		data_drv_stop = Signal()
+		self.sync += If(data_drv_en, data_drv.eq(1)).Elif(data_drv_stop, data_drv.eq(0))
+		self.sync += If(data_drv_en, chooser(rdport.dat_r, counter, data_bit, 8, reverse=True))
+
+		states = ["WAIT_START",
+			"RCV_ADDRESS", "ACK_ADDRESS0", "ACK_ADDRESS1", "ACK_ADDRESS2",
+			"RCV_OFFSET", "ACK_OFFSET0", "ACK_OFFSET1", "ACK_OFFSET2",
+			"READ", "ACK_READ"]
+		fsm = FSM(*states)
+		self.submodules += fsm
+	
+		fsm.act(fsm.RCV_ADDRESS,
+			If(counter == 8,
+				If(din[1:] == 0x50,
+					update_is_read.eq(1),
+					fsm.next_state(fsm.ACK_ADDRESS0)
+				).Else(
+					fsm.next_state(fsm.WAIT_START)
+				)
+			)
+		)
+		fsm.act(fsm.ACK_ADDRESS0,
+			If(~scl_i, fsm.next_state(fsm.ACK_ADDRESS1))
+		)
+		fsm.act(fsm.ACK_ADDRESS1,
+			zero_drv.eq(1),
+			If(scl_i, fsm.next_state(fsm.ACK_ADDRESS2))
+		)
+		fsm.act(fsm.ACK_ADDRESS2,
+			zero_drv.eq(1),
+			If(~scl_i,
+				If(is_read,
+					fsm.next_state(fsm.READ)
+				).Else(
+					fsm.next_state(fsm.RCV_OFFSET)
+				)
+			)
+		)
+
+		fsm.act(fsm.RCV_OFFSET,
+			If(counter == 8,
+				oc_load.eq(1),
+				fsm.next_state(fsm.ACK_OFFSET0)
+			)
+		)
+		fsm.act(fsm.ACK_OFFSET0,
+			If(~scl_i, fsm.next_state(fsm.ACK_OFFSET1))
+		)
+		fsm.act(fsm.ACK_OFFSET1,
+			zero_drv.eq(1),
+			If(scl_i, fsm.next_state(fsm.ACK_OFFSET2))
+		)
+		fsm.act(fsm.ACK_OFFSET2,
+			zero_drv.eq(1),
+			If(~scl_i, fsm.next_state(fsm.RCV_ADDRESS))
+		)
+
+		fsm.act(fsm.READ,
+			If(~scl_i,
+				If(counter == 8,
+					data_drv_stop.eq(1),
+					fsm.next_state(fsm.ACK_READ)
+				).Else(
+					data_drv_en.eq(1)
+				)
+			)
+		)
+		fsm.act(fsm.ACK_READ,
+			If(scl_rising,
+				oc_inc.eq(1),
+				If(sda_i,
+					fsm.next_state(fsm.WAIT_START)
+				).Else(
+					fsm.next_state(fsm.READ)
+				)
+			)
+		)
+
+		for state in states:
+			fsm.act(getattr(fsm, state), If(start, fsm.next_state(fsm.RCV_ADDRESS)))