litex/misoclib/gpio/__init__.py

from migen.fhdl.std import *
from migen.genlib.cdc import MultiReg
from migen.bank.description import *

class GPIOIn(Module, AutoCSR):
	def __init__(self, signal):
		self._r_in = CSRStatus(flen(signal))
		self.specials += MultiReg(signal, self._r_in.status)

class GPIOOut(Module, AutoCSR):
	def __init__(self, signal):
		self._r_out = CSRStorage(flen(signal))
		self.comb += signal.eq(self._r_out.storage)

class GPIOInOut(Module):
	def __init__(self, in_signal, out_signal):
		self.submodules.gpio_in = GPIOIn(in_signal)
		self.submodules.gpio_out = GPIOOut(out_signal)

	def get_csrs(self):
		return self.gpio_in.get_csrs() + self.gpio_out.get_csrs()

class Blinker(Module):
	def __init__(self, signal, divbits=26):
		counter = Signal(divbits)
		self.comb += signal.eq(counter[divbits-1])
		self.sync += counter.eq(counter + 1)