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dvisampler/clocking: proper pix5x reset synchronization
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Sebastien Bourdeauducq committed Mar 18, 2013
1 parent 5126f61 commit 28cb97068c3d4a05e302f89647f42691e6663829
Showing with 16 additions and 1 deletion.
  1. +16 −1 milkymist/dvisampler/clocking.py
@@ -57,5 +57,20 @@ def __init__(self):
self.specials += Instance("BUFG",
Instance.Input("I", pll_clk2), Instance.Output("O", self._cd_pix.clk))
self.specials += MultiReg(locked_async, self.locked, "sys")
self.specials += MultiReg(~locked_async, self._cd_pix5x.rst, "pix5x")
self.comb += self._r_locked.field.w.eq(self.locked)

# sychronize pix5x reset
# this reset is also sampled in the sys clock domain, also guarantee
# a sufficient minimum pulse width.
pix5x_rst_n = 1
for i in range(5):
new_pix5x_rst_n = Signal()
self.specials += Instance("FDCE",
Instance.Input("D", pix5x_rst_n),
Instance.Input("CE", 1),
Instance.Input("C", ClockSignal("pix5x")),
Instance.Input("CLR", ~locked_async),
Instance.Output("Q", new_pix5x_rst_n)
)
pix5x_rst_n = new_pix5x_rst_n
self.comb += self._cd_pix5x.rst.eq(~pix5x_rst_n)

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