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| author | C-Elegans <mtnolan2640@gmail.com> | 2017-06-24 16:13:16 -0400 |
|---|---|---|
| committer | C-Elegans <mtnolan2640@gmail.com> | 2017-06-24 16:30:10 -0400 |
| commit | 7201da8cfd7cc9d75f76656381299db4adcc040e (patch) | |
| tree | 8509e1360f5aceed085da4f24c430071e789029e /icepll | |
| parent | 8611d612d4c40035e377ae9d3417fbd233edb61d (diff) | |
| download | icestorm-7201da8cfd7cc9d75f76656381299db4adcc040e.tar.gz icestorm-7201da8cfd7cc9d75f76656381299db4adcc040e.tar.bz2 icestorm-7201da8cfd7cc9d75f76656381299db4adcc040e.zip | |
Update PLL DIVF range to be [0,127]
As discussed in issue #83, the range of the DIVF parameter in the
iCE40 PLL Usage Guide is incorrectly listed as being 0-63, when it
should actually be 0-127 when used in the SIMPLE feedback mode. This
however does apply in other feedback modes, where the DIVF range should
still be restricted to 0-63
Diffstat (limited to 'icepll')
| -rw-r--r-- | icepll/icepll.cc | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/icepll/icepll.cc b/icepll/icepll.cc index c9b1a45..744b9b1 100644 --- a/icepll/icepll.cc +++ b/icepll/icepll.cc @@ -108,6 +108,15 @@ int main(int argc, char **argv) int best_divf = 0; int best_divq = 0; + //The documentation in the iCE40 PLL Usage Guide incorrectly lists the + //maximum value of DIVF as 63, when it is only limited to 63 when using + //feedback modes other that SIMPLE. + int divf_max = 63; + if(simple_feedback) + { + divf_max = 127; + } + if (f_pllin < 10 || f_pllin > 133) { fprintf(stderr, "Error: PLL input frequency %.3f MHz is outside range 10 MHz - 133 MHz!\n", f_pllin); exit(1); @@ -123,7 +132,7 @@ int main(int argc, char **argv) double f_pfd = f_pllin / (divr + 1); if (f_pfd < 10 || f_pfd > 133) continue; - for (int divf = 0; divf <= 63; divf++) + for (int divf = 0; divf <= divf_max; divf++) { if (simple_feedback) { |