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| author | Maciej Kurc <mkurc@antmicro.com> | 2022-01-28 13:51:10 +0100 |
|---|---|---|
| committer | Maciej Kurc <mkurc@antmicro.com> | 2022-01-28 13:51:10 +0100 |
| commit | e51e82d6a93d2d46ab11601769e736dd5029d70d (patch) | |
| tree | 73341b364324f477c9113cb930cd94d0618b837d /nexus | |
| parent | 1301feb4ad607d5bc7341a1d7059c75077b0e8e9 (diff) | |
| download | nextpnr-e51e82d6a93d2d46ab11601769e736dd5029d70d.tar.gz nextpnr-e51e82d6a93d2d46ab11601769e736dd5029d70d.tar.bz2 nextpnr-e51e82d6a93d2d46ab11601769e736dd5029d70d.zip | |
Added honoring OSCA output frequency tolerance during constraints generation
Signed-off-by: Maciej Kurc <mkurc@antmicro.com>
Diffstat (limited to 'nexus')
| -rw-r--r-- | nexus/pack.cc | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/nexus/pack.cc b/nexus/pack.cc index e89dc9c0..41f9d806 100644 --- a/nexus/pack.cc +++ b/nexus/pack.cc @@ -1987,8 +1987,9 @@ 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); - set_period(ci, id_HFCLKOUT, delay_t((1.0e6 / 450) * (div + 1))); - set_period(ci, id_LFCLKOUT, delay_t((1.0e3 / 10))); + const float tol = 1.15f; // OSCA has +/-15% frequency tolerance, assume the worst case. + set_period(ci, id_HFCLKOUT, delay_t(tol * (1.0e6 / 450) * (div + 1))); + set_period(ci, id_LFCLKOUT, delay_t(tol * (1.0e3 / 10))); } else if (ci->type == id_PLL_CORE) { static const std::array<IdString, 6> div{id_DIVA, id_DIVB, id_DIVC, id_DIVD, id_DIVE, id_DIVF}; static const std::array<IdString, 6> output{id_CLKOP, id_CLKOS, id_CLKOS2, |