humpback-dds/migen/fpga_config.py

from humpback import HumpbackPlatform
from migen.fhdl.module import Module
from migen.fhdl.specials import Instance
from migen.fhdl.bitcontainer import value_bits_sign
from migen.genlib.io import *
from migen.build.lattice.common import LatticeiCE40DifferentialInputImpl
from migen.genlib.io import DifferentialInput


class UrukulConnector(Module):
	def __init__(self, platform):
		# Request EEM I/O & SPI
#		eem = platform.request("eem", 0)
		eem0 = platform.request("eem0", 0);
		eem1 = platform.request("eem0", 1);
#		eem2 = platform.request("eem0", 2);
		eem2 = platform.request("eem0_n", 2);
#		_ignore_eem2 = platform.request("eem0_n", 2);
#		miso = platform.request("miso", 0);
		eem3 = platform.request("eem0", 3);
		eem4 = platform.request("eem0", 4);
		eem5 = platform.request("eem0", 5);
		spi = platform.request("spi")
		led = platform.request("user_led")

		# Assert signal length
		# TODO: Refactor assertion
		assert len(spi.sclk) == 1
		assert len(spi.mosi) == 1
#		assert len(spi.miso) == 1
		assert len(spi.cs) == 3

		# Flip positive signal as negative output, maybe only do it for FPGA outputs
		# self.comb += eem.n.eq(~eem.p)
		self.miso_n = Signal()
		self.sdo = Signal()

		self.specials += Instance("SB_IO",
							p_PIN_TYPE=C(0b000001, 6),
							p_IO_STANDARD="SB_LVDS_INPUT",
							io_PACKAGE_PIN=eem2,
							i_D_OUT_0=self.sdo,
							o_D_IN_0=self.miso_n
						)

#		self.submodules += LatticeiCE40DifferentialInputImpl(eem2.p, eem2.n, spi.miso)
#		self.specials += DifferentialInput(eem2, None, spi.miso)

		# Link EEM to SPI
		self.comb += [

			eem0.p.eq(spi.sclk),
			eem0.n.eq(~spi.sclk),

			eem1.p.eq(spi.mosi),
			eem1.n.eq(~spi.mosi),

#			spi.miso.eq(eem2.p),
			spi.miso.eq(~self.miso_n),

			eem3.p.eq(spi.cs[0]),
			eem3.n.eq(~spi.cs[0]),

			eem4.p.eq(spi.cs[1]),
			eem4.n.eq(~spi.cs[1]),

			eem5.p.eq(spi.cs[2]),
			eem5.n.eq(~spi.cs[2]),

			led.eq(1)
		]



		# Debug purposes: Tie EEM MISO to EEM MOSI
		# self.comb += eem.p[2].eq(eem.p[1])


if __name__ == "__main__":
	platform = HumpbackPlatform()
	platform.build(UrukulConnector(platform))