27 lines
691 B
Python
27 lines
691 B
Python
from migen.fhdl.structure import *
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from migen.fhdl.module import Module
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from migen.bank.description import *
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from migen.bank.eventmanager import *
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class Timer(Module, AutoCSR):
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def __init__(self, width=32):
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self._en = CSRStorage()
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self._value = CSRStorage(width, write_from_dev=True)
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self._reload = CSRStorage(width)
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self.submodules.ev = EventManager()
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self.ev.zero = EventSourceLevel()
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self.ev.finalize()
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###
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self.comb += [
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If(self._value.storage == 0,
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self._value.dat_w.eq(self._reload.storage)
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).Else(
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self._value.dat_w.eq(self._value.storage - 1)
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),
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self._value.we.eq(self._en.storage),
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self.ev.zero.trigger.eq(self._value.storage != 0)
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]
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