icestorm/icepll/icepll.cc

456 lines
12 KiB
C++

//
// Copyright (C) 2015 Claire Xenia Wolf <claire@clairexen.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <math.h>
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#endif
const char *binstr(int v, int n)
{
static char buffer[16];
char *p = buffer;
for (int i = n-1; i >= 0; i--)
*(p++) = ((v >> i) & 1) ? '1' : '0';
*(p++) = 0;
return buffer;
}
void help(const char *cmd)
{
printf("\n");
printf("Usage: %s [options]\n", cmd);
printf("\n");
printf(" -i <input_freq_mhz>\n");
printf(" PLL Input Frequency (default: 12 MHz)\n");
printf("\n");
printf(" -o <output_freq_mhz>\n");
printf(" PLL Output Frequency (default: 60 MHz)\n");
printf("\n");
printf(" -p\n");
printf(" Use SB_PLL40_PAD primitive instead of SB_PLL40_CORE\n");
printf("\n");
printf(" -S\n");
printf(" Disable SIMPLE feedback path mode\n");
printf("\n");
printf(" -b\n");
printf(" Find best input frequency for desired PLL Output frequency\n");
printf(" using the normally stocked oscillators at Mouser\n");
printf("\n");
printf(" -B <filename>\n");
printf(" Find best input frequency for desired PLL Output frequency\n");
printf(" using frequencies read from <filename>\n");
printf("\n");
printf(" -f <filename>\n");
printf(" Save PLL configuration as Verilog to file\n");
printf(" If <filename> is - then the Verilog is written to stdout.\n");
printf("\n");
printf(" -m\n");
printf(" Save PLL configuration as Verilog module (May use with -f)\n");
printf("\n");
printf(" -n <module name>\n");
printf(" Specify different Verilog module name than the default 'pll'\n");
printf("\n");
printf(" -q\n");
printf(" Do not print information about the PLL configuration to stdout\n");
printf("\n");
exit(1);
}
bool analyze(
bool simple_feedback, double f_pllin, double f_pllout,
double *best_fout, int *best_divr, int *best_divf, int *best_divq
)
{
bool found_something = false;
*best_fout = 0;
*best_divr = 0;
*best_divf = 0;
*best_divq = 0;
int divf_max = simple_feedback ? 127 : 63;
// 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.
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);
}
if (f_pllout < 16 || f_pllout > 275) {
fprintf(stderr, "Error: PLL output frequency %.3f MHz is outside range 16 MHz - 275 MHz!\n", f_pllout);
exit(1);
}
for (int divr = 0; divr <= 15; divr++)
{
double f_pfd = f_pllin / (divr + 1);
if (f_pfd < 10 || f_pfd > 133) continue;
for (int divf = 0; divf <= divf_max; divf++)
{
if (simple_feedback)
{
double f_vco = f_pfd * (divf + 1);
if (f_vco < 533 || f_vco > 1066) continue;
for (int divq = 1; divq <= 6; divq++)
{
double fout = f_vco * exp2(-divq);
if (((fabs(fout - f_pllout) < fabs(*best_fout - f_pllout)) && (fout >= 16.0)) || !found_something) {
*best_fout = fout;
*best_divr = divr;
*best_divf = divf;
*best_divq = divq;
found_something = true;
}
}
}
else
{
for (int divq = 1; divq <= 6; divq++)
{
double f_vco = f_pfd * (divf + 1) * exp2(divq);
if (f_vco < 533 || f_vco > 1066) continue;
double fout = f_vco * exp2(-divq);
if (fabs(fout - f_pllout) < fabs(*best_fout - f_pllout) || !found_something) {
*best_fout = fout;
*best_divr = divr;
*best_divf = divf;
*best_divq = divq;
found_something = true;
}
}
}
}
}
return found_something;
}
// Table of frequencies to test in "best" mode defaults to ABRACOM Crystal
// oscillators "Normally stocked" at Mouser
double freq_table[100] =
{
10, 11.0592, 11.2896, 11.7846, 12, 12.288, 12.352, 12.5, 13, 13.5, 13.6, 14.31818, 14.7456, 15, 16, 16.384, 17.2032, 18.432, 19.2, 19.44, 19.6608,
20, 24, 24.576, 25, 26, 27, 27.12, 28.63636, 28.9, 29.4912,
30, 32, 32.768, 33, 33.206, 33.333, 35.328, 36, 37.03, 37.4, 38.4, 38.88,
40, 40.95, 40.97, 44, 44.736, 48,
50, 54, 57.692,
60, 64, 65, 66, 66.666, 68,
70, 72, 75, 76.8,
80, 80.92,
92.16, 96, 98.304,
100, 104, 106.25, 108,
114.285,
120, 122.88, 125,
0
};
void readfreqfile(const char *filename) {
FILE *f;
f = fopen(filename, "r");
if (f == NULL) {
fprintf(stderr, "Error: Can't open file %s!\n",filename);
exit(1);
}
// Clear and overwrite the default values in the table
memset(freq_table, 0, sizeof(freq_table));
int i = 0;
double freq=0;
while((i < int(sizeof(freq_table)/sizeof(double))) && (fscanf(f, "%lf", &freq) > 0))
{
freq_table[i++] = freq;
}
fclose(f);
}
int main(int argc, char **argv)
{
#ifdef __EMSCRIPTEN__
EM_ASM(
if (ENVIRONMENT_IS_NODE)
{
FS.mkdir('/hostcwd');
FS.mount(NODEFS, { root: '.' }, '/hostcwd');
FS.mkdir('/hostfs');
FS.mount(NODEFS, { root: '/' }, '/hostfs');
}
);
#endif
double f_pllin = 12;
double f_pllout = 60;
bool pad = false;
bool simple_feedback = true;
const char* filename = NULL;
bool file_stdout = false;
const char* module_name = NULL;
bool save_as_module = false;
bool best_mode = false;
const char* freqfile = NULL;
bool quiet = false;
int opt;
while ((opt = getopt(argc, argv, "i:o:pSmf:n:bB:q")) != -1)
{
switch (opt)
{
case 'i':
f_pllin = atof(optarg);
break;
case 'o':
f_pllout = atof(optarg);
break;
case 'p':
pad = true;
break;
case 'S':
simple_feedback = false;
break;
case 'm':
save_as_module = true;
break;
case 'f':
filename = optarg;
break;
case 'n':
module_name = optarg;
break;
case 'b':
best_mode = true;
break;
case 'B':
best_mode = true;
freqfile = optarg;
break;
case 'q':
quiet = true;
break;
default:
help(argv[0]);
}
}
if (optind != argc)
help(argv[0]);
// Shall save as module, but no filename was given.
// Write to stdout.
if (save_as_module && filename == NULL)
filename = "-";
// If filename is "-", then use stdout as output stream.
// That implies quiet mode.
if (filename != NULL && strcmp(filename, "-") == 0)
{
file_stdout = true;
quiet = true;
}
if (freqfile) {
readfreqfile(freqfile);
}
bool found_something = false;
double best_fout = 0;
int best_divr = 0;
int best_divf = 0;
int best_divq = 0;
if (!best_mode) {
// Use only specified input frequency
found_something = analyze(simple_feedback, f_pllin, f_pllout, &best_fout, &best_divr, &best_divf, &best_divq);
} else {
// Iterate over all standard crystal frequencies and select the best
for (int i = 0; freq_table[i]>0.0 ; i++)
{
double fout = 0;
int divr = 0;
int divf = 0;
int divq = 0;
if (analyze(simple_feedback, freq_table[i], f_pllout, &fout, &divr, &divf, &divq))
{
found_something = true;
if (abs(fout - f_pllout) < abs(best_fout - f_pllout))
{
f_pllin = freq_table[i];
best_fout = fout;
best_divr = divr;
best_divf = divf;
best_divq = divq;
}
}
}
}
double f_pfd = f_pllin / (best_divr + 1);;
double f_vco = f_pfd * (best_divf + 1);
int filter_range =
f_pfd < 17 ? 1 :
f_pfd < 26 ? 2 :
f_pfd < 44 ? 3 :
f_pfd < 66 ? 4 :
f_pfd < 101 ? 5 : 6;
if (!simple_feedback)
f_vco *= exp2(best_divq);
if (!found_something) {
fprintf(stderr, "Error: No valid configuration found!\n");
exit(1);
}
if (!quiet)
{
printf("\n");
printf("F_PLLIN: %8.3f MHz (given)\n", f_pllin);
printf("F_PLLOUT: %8.3f MHz (requested)\n", f_pllout);
printf("F_PLLOUT: %8.3f MHz (achieved)\n", best_fout);
printf("\n");
printf("FEEDBACK: %s\n", simple_feedback ? "SIMPLE" : "NON_SIMPLE");
printf("F_PFD: %8.3f MHz\n", f_pfd);
printf("F_VCO: %8.3f MHz\n", f_vco);
printf("\n");
printf("DIVR: %2d (4'b%s)\n", best_divr, binstr(best_divr, 4));
printf("DIVF: %2d (7'b%s)\n", best_divf, binstr(best_divf, 7));
printf("DIVQ: %2d (3'b%s)\n", best_divq, binstr(best_divq, 3));
printf("\n");
printf("FILTER_RANGE: %d (3'b%s)\n", filter_range, binstr(filter_range, 3));
printf("\n");
}
// save PLL configuration as file/stdout.
if (filename != NULL || file_stdout)
{
FILE *f;
if (file_stdout)
{
// use stdout as output stream.
f = stdout;
}
else
{
// open file for writing
f = fopen(filename, "w");
if (f == NULL)
{
fprintf(stderr, "Error: Failed to open output file '%s': %s\n",
filename, strerror(errno));
exit(1);
}
}
if (save_as_module)
{
// save PLL configuration as Verilog module
// header
fprintf(f, "/**\n * PLL configuration\n *\n"
" * This Verilog module was generated automatically\n"
" * using the icepll tool from the IceStorm project.\n"
" * Use at your own risk.\n"
" *\n"
" * Given input frequency: %8.3f MHz\n"
" * Requested output frequency: %8.3f MHz\n"
" * Achieved output frequency: %8.3f MHz\n"
" */\n\n",
f_pllin, f_pllout, best_fout);
// generate Verilog module
fprintf(f, "module %s(\n"
"\tinput clock_in,\n"
"\toutput clock_out,\n"
"\toutput locked\n"
"\t);\n\n", (module_name ? module_name : "pll")
);
// save iCE40 PLL tile configuration
fprintf(f, "%s #(\n", (pad ? "SB_PLL40_PAD" : "SB_PLL40_CORE"));
fprintf(f, "\t\t.FEEDBACK_PATH(\"%s\"),\n", (simple_feedback ? "SIMPLE" : "NON_SIMPLE"));
fprintf(f, "\t\t.DIVR(4'b%s),\t\t" "// DIVR = %2d\n", binstr(best_divr, 4), best_divr);
fprintf(f, "\t\t.DIVF(7'b%s),\t" "// DIVF = %2d\n", binstr(best_divf, 7), best_divf);
fprintf(f, "\t\t.DIVQ(3'b%s),\t\t" "// DIVQ = %2d\n", binstr(best_divq, 3), best_divq);
fprintf(f, "\t\t.FILTER_RANGE(3'b%s)\t" "// FILTER_RANGE = %d\n", binstr(filter_range, 3), filter_range);
fprintf(f, "\t) uut (\n"
"\t\t.LOCK(locked),\n"
"\t\t.RESETB(1'b1),\n"
"\t\t.BYPASS(1'b0),\n"
"\t\t.%s(clock_in),\n"
"\t\t.PLLOUTCORE(clock_out)\n"
"\t\t);\n\n", (pad ? "PACKAGEPIN":"REFERENCECLK")
);
fprintf(f, "endmodule\n");
}
else
{
// only save PLL configuration values
// header
fprintf(f, "/**\n * PLL configuration\n *\n"
" * This Verilog header file was generated automatically\n"
" * using the icepll tool from the IceStorm project.\n"
" * It is intended for use with FPGA primitives SB_PLL40_CORE,\n"
" * SB_PLL40_PAD, SB_PLL40_2_PAD, SB_PLL40_2F_CORE or SB_PLL40_2F_PAD.\n"
" * Use at your own risk.\n"
" *\n"
" * Given input frequency: %8.3f MHz\n"
" * Requested output frequency: %8.3f MHz\n"
" * Achieved output frequency: %8.3f MHz\n"
" */\n\n",
f_pllin, f_pllout, best_fout);
// PLL configuration
fprintf(f, ".FEEDBACK_PATH(\"%s\"),\n", (simple_feedback ? "SIMPLE" : "NON_SIMPLE"));
fprintf(f, ".DIVR(4'b%s),\t\t" "// DIVR = %2d\n", binstr(best_divr, 4), best_divr);
fprintf(f, ".DIVF(7'b%s),\t" "// DIVF = %2d\n", binstr(best_divf, 7), best_divf);
fprintf(f, ".DIVQ(3'b%s),\t\t" "// DIVQ = %2d\n", binstr(best_divq, 3), best_divq);
fprintf(f, ".FILTER_RANGE(3'b%s)\t" "// FILTER_RANGE = %d\n", binstr(filter_range, 3), filter_range);
}
fclose(f);
if (!quiet)
printf("PLL configuration written to: %s\n", filename);
}
return 0;
}