from migen.fhdl.structure import * from migen.fhdl.module import Module from migen.bank.description import * from migen.bank.eventmanager import * class Timer(Module, AutoCSR): def __init__(self, width=32): self._load = CSRStorage(width) self._reload = CSRStorage(width) self._en = CSRStorage() self._update_value = CSR() self._value = CSRStatus(width) self.submodules.ev = EventManager() self.ev.zero = EventSourceProcess() self.ev.finalize() ### value = Signal(width) self.sync += [ If(self._en.storage, If(value == 0, # set reload to 0 to disable reloading value.eq(self._reload.storage) ).Else( value.eq(value - 1) ) ).Else( value.eq(self._load.storage) ), If(self._update_value.re, self._value.status.eq(value)) ] self.comb += self.ev.zero.trigger.eq(value != 0)