mirror of
git://projects.qi-hardware.com/ben-wpan.git
synced 2024-11-26 00:39:20 +02:00
101 lines
2.1 KiB
C
101 lines
2.1 KiB
C
|
/*
|
||
|
|
* atrf-xtal/atusb.c - ATUSB-specific driver and evaluation
|
||
|
|
*
|
||
|
|
* Written 2011 by Werner Almesberger
|
||
|
|
* Copyright 2011 Werner Almesberger
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or modify
|
||
|
|
* it under the terms of the GNU General Public License as published by
|
||
|
|
* the Free Software Foundation; either version 2 of the License, or
|
||
|
|
* (at your option) any later version.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <sys/time.h>
|
||
|
|
|
||
|
|
#include <usb.h>
|
||
|
|
#include <gsl/gsl_fit.h>
|
||
|
|
|
||
|
|
#include "at86rf230.h"
|
||
|
|
#include "atusb/ep0.h"
|
||
|
|
#include "atrf.h"
|
||
|
|
|
||
|
|
#include "atrf-xtal.h"
|
||
|
|
|
||
|
|
|
||
|
|
#define FROM_DEV ATUSB_FROM_DEV(0)
|
||
|
|
|
||
|
|
#define F_NOMINAL_Hz 8000000 /* nominal frequency, in Hz */
|
||
|
|
|
||
|
|
|
||
|
|
static uint64_t get_sample(struct atrf_dsc *dsc, double *t0, double *t1)
|
||
|
|
{
|
||
|
|
struct timeval tod0, tod1;
|
||
|
|
uint64_t cnt;
|
||
|
|
int res;
|
||
|
|
|
||
|
|
gettimeofday(&tod0, NULL);
|
||
|
|
res = usb_control_msg(atrf_usb_handle(dsc),
|
||
|
|
FROM_DEV, ATUSB_TIMER, 0, 0, (void *) &cnt, sizeof(cnt), 1000);
|
||
|
|
gettimeofday(&tod1, NULL);
|
||
|
|
if (res < 0) {
|
||
|
|
fprintf(stderr, "ATUSB_TIMER: %s\n", usb_strerror());
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
*t0 = tod0.tv_sec+tod0.tv_usec/1000000.0;
|
||
|
|
*t1 = tod1.tv_sec+tod1.tv_usec/1000000.0;
|
||
|
|
return cnt;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
void do_atusb(struct atrf_dsc *dsc, int trim, int dump_raw, double ppm,
|
||
|
|
int n)
|
||
|
|
{
|
||
|
|
double t0[n], t1[n], cnt[n], w[n];
|
||
|
|
double c0, c1, cov00, cov01, cov11, chisq;
|
||
|
|
double d;
|
||
|
|
double tz = 0, cntz = 0;
|
||
|
|
double rel;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
atrf_reg_write(dsc, REG_XOSC_CTRL,
|
||
|
|
(XTAL_MODE_INT << XTAL_MODE_SHIFT) | trim);
|
||
|
|
|
||
|
|
for (i = 0; i != n; i++) {
|
||
|
|
cnt[i] = get_sample(dsc, t0+i, t1+i);
|
||
|
|
if (!i) {
|
||
|
|
tz = t0[0];
|
||
|
|
cntz = cnt[0];
|
||
|
|
}
|
||
|
|
t0[i] -= tz;
|
||
|
|
t1[i] -= tz;
|
||
|
|
cnt[i] -= cntz;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* see http://en.wikipedia.org/wiki/
|
||
|
|
* Uniform_distribution_(continuous)
|
||
|
|
*/
|
||
|
|
d = (t1[i]-t0[i])*F_NOMINAL_Hz;
|
||
|
|
w[i] = 12/(d*d);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (dump_raw) {
|
||
|
|
for (i = 0; i != n; i++)
|
||
|
|
printf("%.6f %.6f %.0f\n", t0[i], t1[i], cnt[i]);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
gsl_fit_wlinear (t0, 1, w, 1, cnt, 1, n,
|
||
|
|
&c0, &c1, &cov00, &cov01, &cov11, &chisq);
|
||
|
|
|
||
|
|
rel = (c1/F_NOMINAL_Hz-1)*1000000;
|
||
|
|
printf("%+.2f ppm", rel);
|
||
|
|
if (ppm && fabs(rel) > ppm) {
|
||
|
|
printf(" (outside bounds)\n");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
putchar('\n');
|
||
|
|
}
|