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DDMTD: replace FD with ISERDESE2 #292

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sb10q merged 2 commits from morgan/artiq-zynq:DDMTD into master 2024-04-29 13:03:30 +08:00
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1 changed files with 38 additions and 12 deletions
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src/gateware/ddmtd.py
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@ -10,18 +10,44 @@ class DDMTDSampler(Module):
# # # # # #
sb10q commented 2024-04-29 11:20:05 +08:00
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Move closer to IDELAYE2 instantiation. This is just an internal signal used to make routing possible, not part of the module's interface.

Move closer to IDELAYE2 instantiation. This is just an internal signal used to make routing possible, not part of the module's interface.
ref_beating_FF = Signal() ref_clk = Signal()
main_beating_FF = Signal()
self.specials +=[ self.specials +=[
# Two back to back FFs are used to prevent metastability # ISERDESE2 can only be driven from fabric via IDELAYE2 (see UG471)
Instance("FD", i_C=ClockSignal("helper"), Instance("IDELAYE2",
i_D=cd_ref.clk, o_Q=ref_beating_FF), p_DELAY_SRC="DATAIN",
Instance("FD", i_C=ClockSignal("helper"), p_HIGH_PERFORMANCE_MODE="TRUE",
i_D=ref_beating_FF, o_Q=self.ref_beating), p_REFCLK_FREQUENCY=208.3, # REFCLK frequency from IDELAYCTRL
Instance("FD", i_C=ClockSignal("helper"), p_IDELAY_VALUE=0,
i_D=main_clk_se, o_Q=main_beating_FF),
Instance("FD", i_C=ClockSignal("helper"), i_DATAIN=cd_ref.clk,
i_D=main_beating_FF, o_Q=self.main_beating)
o_DATAOUT=ref_clk
),
Instance("ISERDESE2",
p_IOBDELAY="IFD", # use DDLY as input
p_DATA_RATE="SDR",
p_DATA_WIDTH=2, # min is 2
p_NUM_CE=1,
i_DDLY=ref_clk,
i_CE1=1,
i_CLK=ClockSignal("helper"),
i_CLKDIV=ClockSignal("helper"),
o_Q1=self.ref_beating
),
Instance("ISERDESE2",
p_DATA_RATE="SDR",
p_DATA_WIDTH=2, # min is 2
p_NUM_CE=1,
i_D=main_clk_se,
i_CE1=1,
i_CLK=ClockSignal("helper"),
i_CLKDIV=ClockSignal("helper"),
o_Q1=self.main_beating,
),
] ]