caiyu/nextpnr
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge pull request #900 from antmicro/nexus-osc-tolerance

Browse Source 
Honor nexus OSCA frequency tolerance
This commit is contained in:
gatecat 2022-01-28 19:19:33 +00:00 committed by GitHub
commit e069b3bc6a
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
nexus/pack.cc
View File

@ -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,