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pipistrello: try simpler constraints

This commit is contained in:
Robert Jördens 2015-07-04 21:08:28 -06:00
parent 6faa8ecd51
commit 959ba99f1c
1 changed files with 4 additions and 6 deletions
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10
soc/targets/artiq_pipistrello.py
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@ -35,7 +35,10 @@ class _RTIOCRG(Module, AutoCSR):
i_RST=ResetSignal())
rtio_external_clk = platform.request("pmt", 2)
platform.add_period_constraint(rtio_external_clk, 8.0)
# ISE infers constraints for the internal clock
# and propagates them through the BUFGMUX. Adding this:
# platform.add_period_constraint(rtio_external_clk, 8.0)
# seems to confuse it
self.specials += Instance("BUFGMUX",
i_I0=rtio_internal_clk,
i_I1=rtio_external_clk,
@ -44,14 +47,9 @@ class _RTIOCRG(Module, AutoCSR):
platform.add_platform_command("""
NET "{int_clk}" TNM_NET = "GRPint_clk";
NET "{ext_clk}" TNM_NET = "GRPext_clk";
NET "sys_clk" TNM_NET = "GRPsys_clk";
TIMESPEC "TSfix_ise1" = FROM "GRPint_clk" TO "GRPsys_clk" TIG;
TIMESPEC "TSfix_ise2" = FROM "GRPsys_clk" TO "GRPint_clk" TIG;
TIMESPEC "TSfix_ise3" = FROM "GRPext_clk" TO "GRPsys_clk" TIG;
TIMESPEC "TSfix_ise4" = FROM "GRPsys_clk" TO "GRPext_clk" TIG;
TIMESPEC "TSfix_ise5" = FROM "GRPext_clk" TO "GRPint_clk" TIG;
TIMESPEC "TSfix_ise6" = FROM "GRPint_clk" TO "GRPext_clk" TIG;
""", int_clk=rtio_internal_clk, ext_clk=rtio_external_clk)