tools: new utility atrf-path to measure path characteristics

- Makefile (DIRS): added atrf-path
- atrf-path/Makefile, atrf-path/atrf-path.c: new utility atrf-path to
  measure path characteristics (for now, TX-to-RX path attenuation)
- atrf-path/plot: visualize path loss measurements

tools/Makefile

@@ -11,7 +11,7 @@
 #
 
 
-DIRS=atrf-id atrf-proxy atrf-reset atrf-rssi atrf-trim atrf-txrx \
+DIRS=atrf-id atrf-path atrf-proxy atrf-reset atrf-rssi atrf-trim atrf-txrx \
      atrf-xtal
 TARGET_ONLY_DIRS=lib
 

tools/atrf-path/Makefile

@@ -0,0 +1,16 @@
+#
+# atrf-path/Makefile - Measure path characteristics
+#
+# 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.
+#
+
+
+MAIN = atrf-path
+
+include ../Makefile.common

tools/atrf-path/atrf-path.c

@@ -0,0 +1,183 @@
+/*
+ * atrf-path/atrf-path.c - Measure path characteristics
+ *
+ * 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 "at86rf230.h"
+
+#include "misctxrx.h"
+#include "cwtest.h"
+#include "atrf.h"
+
+
+#define	DEFAULT_TRIM	8
+#define	DEFAULT_POWER	15
+
+
+static void init_common(struct atrf_dsc *dsc, int trim, int chan)
+{
+	atrf_reg_write(dsc, REG_TRX_STATE, TRX_CMD_TRX_OFF);
+	atrf_reg_write(dsc, REG_XOSC_CTRL,
+	    (XTAL_MODE_INT << XTAL_MODE_SHIFT) | trim);
+	atrf_set_clkm(dsc, 0);
+	atrf_reg_write(dsc, REG_PHY_CC_CCA, (1 << CCA_MODE_SHIFT) | chan);
+}
+
+
+static void init_tx(struct atrf_dsc *dsc, int trim, int power, int chan)
+{
+	init_common(dsc, trim, chan);
+	set_power_step(dsc, power, 0);
+}
+
+
+static void init_rx(struct atrf_dsc *dsc, int trim, int chan)
+{
+	init_common(dsc, trim, chan);
+	atrf_reg_write(dsc, REG_TRX_STATE, TRX_CMD_RX_ON);
+}
+
+
+static void sample(struct atrf_dsc *tx, struct atrf_dsc *rx, int trim_tx,
+    int power, int chan, int cont_tx, int samples)
+{
+	int i, rssi = 0;
+	double offset = tx_power_step2dBm(tx, power);
+
+	init_tx(tx, trim_tx, power, chan);
+	usleep(155);	/* table 7-2, tTR19 */
+
+	cw_test_begin(tx, cont_tx);
+	/* table 7-1, tTR10, doubling since it's a "typical" value */
+	usleep(2*16);
+
+	for (i = 0; i != samples; i++) {
+		/* according to 8.3.2, PHY_RSSI is updated every 2 us */
+		usleep(2);
+
+		rssi += atrf_reg_read(rx, REG_PHY_RSSI) & RSSI_MASK;
+	}
+
+	cw_test_end(tx);
+
+	printf("%.1f %.1f\n",
+	    2350+5*chan+(cont_tx == CONT_TX_M500K ? -0.5 : 0.5),
+	    -91+3*(rssi-1.0)/samples-offset);
+}
+
+
+static void do_sweeps(struct atrf_dsc *tx, struct atrf_dsc *rx,
+    int trim_tx, int trim_rx, int power, int sweeps, int samples)
+{
+	int i, chan;
+
+	for (i = 0; i != sweeps; i++) {
+		if (i)
+			putchar('\n');
+		for (chan = 11; chan <= 26; chan++) {
+			init_rx(rx, trim_rx, chan);
+
+			sample(tx, rx, trim_tx, power, chan, CONT_TX_M500K,
+			    samples);
+			sample(tx, rx, trim_tx, power, chan, CONT_TX_P500K,
+			    samples);
+		}
+	}
+}
+
+
+static void usage(const char *name)
+{
+	fprintf(stderr,
+"usage: %s [-p power] [-t trim_tx [-t trim_rx]] driver_tx[:arg]\n"
+"%16s driver_rx[:arg] [sweeps [samples]]\n\n"
+"  -p power  transmit power, 0 to 15 (default %d)\n"
+"  -t trim   trim capacitor, 0 to 15 (default %d)\n"
+    , name, "", DEFAULT_POWER, DEFAULT_TRIM);
+	exit(1);
+}
+
+
+int main(int argc, char **argv)
+{
+	const char *tx_drv, *rx_drv;
+	struct atrf_dsc *tx, *rx;
+	int trim_tx = -1, trim_rx = DEFAULT_TRIM;
+	int power = DEFAULT_POWER;
+	int sweeps = 1, samples = 1;
+	unsigned long tmp;
+	char *end;
+	int c;
+
+	while ((c = getopt(argc, argv, "p:t:")) != EOF)
+		switch (c) {
+		case 'p':
+			tmp = strtoul(optarg, &end, 0);
+			if (*end || tmp > 15)
+				usage(*argv);
+			power = tmp;
+			break;
+		case 't':
+			tmp = strtoul(optarg, &end, 0);
+			if (*end || tmp > 15)
+				usage(*argv);
+			if (trim_tx == -1)
+				trim_tx = tmp;
+			else
+				trim_rx = tmp;
+			break;
+		default:
+			usage(*argv);
+		}
+
+	if (trim_tx == -1)
+		trim_tx = DEFAULT_TRIM;
+
+	switch (argc-optind) {
+	case 4:
+		samples = strtoul(argv[optind+3], &end, 0);
+		if (*end)
+			usage(*argv);
+		/* fall through */
+	case 3:
+		sweeps = strtoul(argv[optind+2], &end, 0);
+		if (*end)
+			usage(*argv);
+		/* fall through */
+	case 2:
+		tx_drv = argv[optind];
+		rx_drv = argv[optind+1];
+		break;
+	default:
+		usage(*argv);
+	}
+
+	tx = atrf_open(tx_drv);
+	if (!tx)
+		return 1;
+	rx = atrf_open(rx_drv);
+	if (!rx)
+		return 1;
+
+	do_sweeps(tx, rx, trim_tx, trim_rx, 15-power, sweeps, samples);
+
+	atrf_reg_write(tx, REG_TRX_STATE, TRX_CMD_TRX_OFF);
+	atrf_reg_write(rx, REG_TRX_STATE, TRX_CMD_TRX_OFF);
+
+	atrf_close(tx);
+	atrf_close(rx);
+
+	return 0;
+}

tools/atrf-path/plot

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+usage()
+{
+	echo "usage: file ..." 1>&2
+	exit 1
+}
+
+[ "$1" ] || usage
+files=
+while [ "$1" ]; do
+	[ "$files" ] && files="$files, "
+	files="$files\"$1\""
+	shift
+done
+
+gnuplot -persist <<EOF
+set yrange [-94:-10]
+set ylabel "RX-TX power (dBm)"
+set xlabel "Frequency (MHz)"
+set style data lines
+plot $files
+EOF