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
		eem0 = [
			platform.request("eem0", 0),
			platform.request("eem0", 1),
			platform.request("eem0_n", 2),
			platform.request("eem0", 3),
			platform.request("eem0", 4),
			platform.request("eem0", 5),
			platform.request("eem0", 6)
		]
		spi = platform.request("spi")
		led = platform.request("user_led")
		io_update = platform.request("io_update")

		# Assert SPI resource length
		assert len(spi.sclk) == 1
		assert len(spi.mosi) == 1
		assert len(spi.miso) == 1
		assert len(spi.cs) == 3

		# TODO: Assert EEM resources
		assert isinstance(eem0, list)

		# Flip positive signal as negative output, maybe only do it for FPGA outputs
		self.miso_n = Signal()

		# Very similar setup to Diff setup for iCE40 suggested, but gave B pin instead
		self.specials += Instance("SB_IO",
							p_PIN_TYPE=C(0b000001, 6),
							p_IO_STANDARD="SB_LVDS_INPUT",
							io_PACKAGE_PIN=eem0[2],
							o_D_IN_0=self.miso_n
						)

		# Link EEM to SPI
		self.comb += [

			eem0[0].p.eq(spi.sclk),
			eem0[0].n.eq(~spi.sclk),

			eem0[1].p.eq(spi.mosi),
			eem0[1].n.eq(~spi.mosi),

			spi.miso.eq(~self.miso_n),

			eem0[3].p.eq(spi.cs[0]),
			eem0[3].n.eq(~spi.cs[0]),

			eem0[4].p.eq(spi.cs[1]),
			eem0[4].n.eq(~spi.cs[1]),

			eem0[5].p.eq(spi.cs[2]),
			eem0[5].n.eq(~spi.cs[2]),

			eem0[6].p.eq(io_update),
			eem0[6].n.eq(~io_update),

			led.eq(1)
		]


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