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targets/kc705: pre-divide input RTIO clock to improve non-50% duty cycle tolerance

This commit is contained in:
Sebastien Bourdeauducq 2015-12-29 17:00:57 +08:00
parent aa29defd02
commit 04b0db1a91
1 changed files with 18 additions and 4 deletions
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22
artiq/gateware/targets/kc705.py
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@ -45,6 +45,18 @@ class _RTIOCRG(Module, AutoCSR):
i_I=user_sma_clock.p, i_IB=user_sma_clock.n,
o_O=rtio_external_clk)
rtio_half_internal_clk = Signal()
self.specials += Instance("BUFR",
p_BUFR_DIVIDE="2", i_CE=1, i_CLR=0,
i_I=rtio_internal_clk,
o_O=rtio_half_internal_clk)
rtio_half_external_clk = Signal()
self.specials += Instance("BUFR",
p_BUFR_DIVIDE="2", i_CE=1, i_CLR=0,
i_I=rtio_external_clk,
o_O=rtio_half_external_clk)
pll_locked = Signal()
rtio_clk = Signal()
rtiox4_clk = Signal()
@ -54,13 +66,15 @@ class _RTIOCRG(Module, AutoCSR):
p_STARTUP_WAIT="FALSE", o_LOCKED=pll_locked,
p_REF_JITTER1=0.01,
p_CLKIN1_PERIOD=8.0, p_CLKIN2_PERIOD=8.0,
i_CLKIN1=rtio_internal_clk, i_CLKIN2=rtio_external_clk,
p_CLKIN1_PERIOD=16.0, p_CLKIN2_PERIOD=16.0,
i_CLKIN1=rtio_half_internal_clk,
i_CLKIN2=rtio_half_external_clk,
# Warning: CLKINSEL=0 means CLKIN2 is selected
i_CLKINSEL=~self._clock_sel.storage,
# VCO @ 1GHz when using 125MHz input
p_CLKFBOUT_MULT=8, p_DIVCLK_DIVIDE=1,
# VCO @ 1GHz when using 62.5MHz input at the PLL
# (125MHz on SMA)
p_CLKFBOUT_MULT=16, p_DIVCLK_DIVIDE=1,
i_CLKFBIN=self.cd_rtio.clk,
i_RST=self._pll_reset.storage,