tools/atrf-xtal: new utility to measure the crystal frequency

- Makefile (DIRS): added atrf-xtal
- atrf-xtal/Makefile: build atrf-xtal for the Ben or do nothing elsewhere
- atrf-xtal/atrf-xtal.h, atrf-xtal/atrf-xtal.c: diagnostic utility to
  determine the transceiver's crystal frequency
- atrf-xtal/atben.c: dirty low-level driver for ATBEN

tools/atrf-xtal/atrf-xtal.c

@@ -0,0 +1,170 @@
+/*
+ * atrf-xtal/atrf-xtal.c - AT86RF230/1 crystal diagnostic utility
+ *
+ * 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 <unistd.h>
+
+#include "atrf.h"
+
+#include "atrf-xtal.h"
+
+
+#define	DEFAULT_SIZE	127
+#define	DEFAULT_TRIM	8
+
+
+static void setup(struct atrf_dsc *dsc, int size, int trim)
+{
+#ifdef __mips__
+	atben_setup(dsc, size, trim);
+#else
+#error	Only ATBEN is supported for now
+#endif
+}
+
+
+unsigned sample(struct atrf_dsc *dsc)
+{
+#ifdef __mips__
+	return atben_sample(dsc);
+#else
+#error	Only ATBEN is supported for now
+#endif
+}
+
+
+void cleanup(struct atrf_dsc *dsc)
+{
+#ifdef __mips__
+	atben_cleanup(dsc);
+#else
+#error	Only ATBEN is supported for now
+#endif
+}
+
+
+static int cmp(const void *a, const void *b)
+{
+	return *(unsigned *) a-*(unsigned *) b;
+}
+
+
+
+static void eval(unsigned *res, int rep)
+{
+	double sum = 0;
+	int n = 0;
+	int i;
+
+	qsort(res, rep, sizeof(*res), cmp);
+	if (rep < 8) {
+		printf("%u\n", res[rep >> 1]);
+		return;
+	}
+	for (i = rep/8; i != rep-rep/8; i++) {
+		sum += res[i];
+		n++;
+	}
+	printf("%f\n", (double) sum/n);
+}
+
+
+static void usage(const char *name)
+{
+	fprintf(stderr,
+"%s [-d] [-s size] [-t trim] [repetitions]\n"
+"  -d           instead of printing a mean value, dump all samples\n"
+"  -s size      payload size in bytes, 0-127 (default: %d bytes)\n"
+"  -t trim      trim capacitor setting, 0-15 (default: %d)\n"
+"  repetitions  number of measurements (default: 1)\n"
+  , name, DEFAULT_SIZE, DEFAULT_TRIM);
+	exit(1);
+}
+
+
+int main(int argc, char *const *argv)
+{
+	struct atrf_dsc *dsc;
+	int size = DEFAULT_SIZE;
+	int trim = DEFAULT_TRIM;
+	int rep = 1;
+	int dump = 0;
+	char *end;
+	unsigned *res;
+	int c, i;
+
+	while ((c = getopt(argc, argv, "ds:t:")) != EOF)
+		switch (c) {
+		case 'd':
+			dump = 1;
+			break;
+		case 's':
+			size = strtoul(optarg, &end, 0);
+			if (*end)
+				usage(*argv);
+			if (size > 127)
+				usage(*argv);
+			break;
+		case 't':
+			trim = strtoul(optarg, &end, 0);
+			if (*end)
+				usage(*argv);
+			if (trim > 15)
+				usage(*argv);
+			break;
+		default:
+			usage(*argv);
+		}
+
+	switch (argc-optind) {
+	case 0:
+		break;
+	case 1:
+		rep = strtoul(argv[optind], &end, 0);
+		if (*end)
+			usage(*argv);
+		break;
+	default:
+		usage(*argv);
+	}
+
+	res = malloc(rep*sizeof(*res));
+	if (!res) {
+		perror("malloc");
+		exit(1);
+	}
+
+	dsc = atrf_open();
+	if (!dsc)
+		return 1;
+
+	setup(dsc, size, trim);
+
+	for (i = 0; i != rep; i++)
+		res[i] = sample(dsc);
+
+	cleanup(dsc);
+
+	atrf_close(dsc);
+
+	if (dump) {
+		for (i = 0; i != rep; i++)
+			printf("%u\n", res[i]);
+		exit(0);
+	}
+
+	eval(res, rep);
+	
+	return 0;
+}