diff options
| author | C-Elegans <mtnolan2640@gmail.com> | 2017-06-24 16:13:16 -0400 |
|---|---|---|
| committer | Clifford Wolf <clifford@clifford.at> | 2017-07-04 12:12:13 +0200 |
| commit | e395b747995758c2ce70c65924dcdf7cbca4f880 (patch) | |
| tree | cbe01e2f6e90670326aeb2897a69aeaa0a7f30cf | |
| parent | b00ffb1c091b65ed6c741dde74a4e7d5f709efd1 (diff) | |
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
| -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) { |