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siphaser: support external reference for the freerunning 150MHz

This commit is contained in:
Sebastien Bourdeauducq 2018-05-12 22:57:11 +08:00
parent 6796413a53
commit 2426fea3f2
1 changed files with 9 additions and 7 deletions
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16
artiq/gateware/drtio/siphaser.py
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@ -4,16 +4,17 @@ from migen.genlib.cdc import MultiReg
from misoc.interconnect.csr import *
# This code assumes 125MHz system clock and 150MHz RTIO frequency.
# This code assumes 125/62.5MHz reference clock and 150MHz RTIO frequency.
class SiPhaser7Series(Module, AutoCSR):
def __init__(self, si5324_clkin, si5324_clkout_fabric):
def __init__(self, si5324_clkin, si5324_clkout_fabric,
ref_clk=None, ref_div2=False):
self.switch_clocks = CSRStorage()
self.phase_shift = CSR()
self.phase_shift_done = CSRStatus(reset=1)
self.sample_result = CSRStatus()
# 125MHz system clock to 150MHz. VCO @ 625MHz.
# 125MHz/62.5MHz reference clock to 150MHz. VCO @ 625MHz.
# Used to provide a startup clock to the transceiver through the Si,
# we do not use the crystal reference so that the PFD (f3) frequency
# can be high.
@ -21,11 +22,12 @@ class SiPhaser7Series(Module, AutoCSR):
mmcm_freerun_output = Signal()
self.specials += \
Instance("MMCME2_BASE",
p_CLKIN1_PERIOD=1e9/125e6,
i_CLKIN1=ClockSignal("sys"),
i_RST=ResetSignal("sys"),
p_CLKIN1_PERIOD=16.0 if ref_div2 else 8.0,
i_CLKIN1=ClockSignal("sys") if ref_clk is None else ref_clk,
i_RST=ResetSignal("sys") if ref_clk is None else 0,
p_CLKFBOUT_MULT_F=6.0, p_DIVCLK_DIVIDE=1,
p_CLKFBOUT_MULT_F=12.0 if ref_div2 else 6.0,
p_DIVCLK_DIVIDE=1,
o_CLKFBOUT=mmcm_freerun_fb, i_CLKFBIN=mmcm_freerun_fb,