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ben-wpan/tools/atrf-xtal/atusb.c
Werner Almesberger 61e656e143 atrf-xtal: added atusb support (via ATUSB_TIMER)
- Makefile: removed limitation to Ben and added host build
- atusb.c: atusb-specific acquisition and calculations
- atrf-xtal.h (do_atusb): interface to atusb.c
- atrf-xtal.c (atben, atusb, main): added switch to board-specific driver
- atrf-xtal.c (usage, main): added support for atusb
2011-05-30 19:17:43 -03:00

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');
}