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Merge pull request #912 from danc86/nexus-osca-7percent

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nexus: reduce OSCA worst case to 7%
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gatecat 2022-02-10 11:21:18 +00:00 committed by GitHub
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nexus/pack.cc
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@ -1987,7 +1987,7 @@ struct NexusPacker
copy_constraint(ci, id_CLKI, id_CLKO, 1);
} else if (ci->type == id_OSC_CORE) {
int div = int_or_default(ci->params, ctx->id("HF_CLK_DIV"), 128);
const float tol = 1.15f; // OSCA has +/-15% frequency tolerance, assume the worst case.
const float tol = 1.07f; // OSCA has +/-7% frequency tolerance, assume the worst case.
set_period(ci, id_HFCLKOUT, delay_t((1.0e6 / 450) * (div + 1) / tol));
set_period(ci, id_LFCLKOUT, delay_t((1.0e3 / 10) / tol));
} else if (ci->type == id_PLL_CORE) {