atrf-path: new option -T to sweep only one offset

atrf-path -T +0.5 -g ... 10 10 time:

before (both offsets)	0.65 s
after (one offset)	0.32-0.33 s	(50%)

- atrf-path.c (usage, main): new option -T to specify which offset to
  sweep (default: sweep both)
- atrf-path.c (do_half_sweep): only sample points with the desired offset
- atrf-path.c (print_sweep): only prints points we've sweeped
- gui.c (segment, draw): inverted flag logic from "have_last" to "first"
- gui.c (draw): only plot points we've sweeped
- gui.c (gui): pass the offset selection to "draw"

tools/atrf-path/atrf-path.c

@@ -14,6 +14,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <string.h>
 
 #include "at86rf230.h"
 
@@ -111,6 +112,8 @@ static void do_half_sweep(const struct sweep *sweep, int cont_tx,
 {
 	int chan;
 
+	if (sweep->cont_tx && sweep->cont_tx != cont_tx)
+		return;
 	for (chan = 11; chan <= 26; chan++) {
 		set_channel(sweep->rx, chan);
 		set_channel(sweep->tx, chan);
@@ -134,9 +137,11 @@ static void print_sweep(const struct sweep *sweep, const struct sample *res)
 	int chan;
 
 	for (chan = 11; chan <= 26; chan++) {
+		if (sweep->cont_tx != CONT_TX_P500K)
 			printf("%.1f %.2f %.0f %.0f\n",
 			    2350+5*chan-0.5, res->avg, res->min, res->max);
 		res++;
+		if (sweep->cont_tx != CONT_TX_M500K)
 			printf("%.1f %.2f %.0f %.0f\n",
 			    2350+5*chan+0.5, res->avg, res->min, res->max);
 		res++;
@@ -167,14 +172,15 @@ static void usage(const char *name)
 "%6s %s -g common_args [[sweeps] samples]\n"
 #endif
     "\n"
-"  common args:  [-p power] [-t trim_tx [-t trim_rx]] driver_tx[:arg]\n"
+"  common args:  [-p power] [-t trim_tx [-t trim_rx]] [-T offset]\n"
-"                driver_rx[:arg]\n\n"
+"                driver_tx[:arg] driver_rx[:arg]\n\n"
 
 #ifdef HAVE_GFX
 "  -g         display results graphically\n"
 #endif
 "  -p power   transmit power, 0 to 15 (default %d)\n"
 "  -t trim    trim capacitor, 0 to 15 (default %d)\n"
+"  -T offset  constant wave offset in MHz, -0.5 or +0.5 (default: scan both)\n"
 
     , name,
 #ifdef HAVE_GFX
@@ -192,6 +198,7 @@ int main(int argc, char **argv)
 	struct sweep sweep = {
 		.trim_tx = -1,
 		.trim_rx = DEFAULT_TRIM,
+		.cont_tx = 0,
 		.samples = 1,
 	};
 	int graphical = 0;
@@ -201,7 +208,7 @@ int main(int argc, char **argv)
 	char *end;
 	int c;
 
-	while ((c = getopt(argc, argv, "gp:t:")) != EOF)
+	while ((c = getopt(argc, argv, "gp:t:T:")) != EOF)
 		switch (c) {
 		case'g':
 			graphical = 1;
@@ -222,6 +229,14 @@ int main(int argc, char **argv)
 			else
 				sweep.trim_rx = tmp;
 			break;
+		case 'T':
+			if (!strcmp(optarg, "-0.5"))
+				sweep.cont_tx = CONT_TX_M500K;
+			else if (!strcmp(optarg, "+0.5"))
+				sweep.cont_tx = CONT_TX_P500K;
+			else
+				usage(*argv);
+			break;
 		default:
 			usage(*argv);
 		}

tools/atrf-path/gui.c

@@ -47,11 +47,11 @@
 
 
 static void segment(SDL_Surface *s, int *last_x, int *last_y, int x,
-    const struct sample *res, int have_last)
+    const struct sample *res, int first)
 {
 	int y = YRES-(res->avg-Y_MIN)/(Y_MAX-Y_MIN)*YRES-1;
 
-	if (have_last) {
+	if (!first) {
 		aalineColor(s, *last_x, *last_y, x, y, FG_RGBA);
 }
 	*last_x = x;
@@ -59,16 +59,26 @@ static void segment(SDL_Surface *s, int *last_x, int *last_y, int x,
 }
 
 
-static void draw(SDL_Surface *s, const struct sample *res)
+static void draw(SDL_Surface *s, const struct sample *res, int cont_tx)
 {
 	int last_x, last_y;
-	int x, i;
+	int first, x, i;
 
 	x = CHAN_X_OFFSET;
+	first = 1;
 	for (i = 0; i != N_CHAN; i++) {
-		segment(s, &last_x, &last_y, x, res++, i);
+		if (cont_tx != CONT_TX_P500K) {
+			segment(s, &last_x, &last_y, x, res, first);
+			first = 0;
+		}
+		res++;
 		x += 2*SIDE_STEP;
-		segment(s, &last_x, &last_y, x, res++, 1);
+
+		if (cont_tx != CONT_TX_M500K) {
+			segment(s, &last_x, &last_y, x, res, first);
+			first = 0;
+		}
+		res++;
 		x += CHAN_STEP-2*SIDE_STEP;
 	}
 }
@@ -148,7 +158,7 @@ void gui(const struct sweep *sweep, int sweeps)
 			aacircleColor(surf, STATUS_X, STATUS_Y, STATUS_R,
 			    OK_RGBA);
 		}
-		draw(surf, res);
+		draw(surf, res, sweep->cont_tx);
 
 		SDL_UnlockSurface(surf);
 		SDL_UpdateRect(surf, 0, 0, 0, 0);

tools/atrf-path/sweep.h

@@ -14,6 +14,8 @@
 #ifndef	SWEEP_H
 #define	SWEEP_H
 
+#include <stdint.h>
+
 #include "atrf.h"
 
 
@@ -23,6 +25,7 @@ struct sweep {
 	int trim_tx;
 	int trim_rx;
 	int power;
+	uint8_t cont_tx;
 	int samples;
 };