add direct sampling switches to rtl_sdr

Author: Adam

Diff for: src/librtlsdr.c

@@ -1636,17 +1636,17 @@ int rtlsdr_open(rtlsdr_dev_t **out_dev, uint32_t index)
 	if(dev->force_bt) rtlsdr_set_gpio(dev, 0, 1);
 	/* Hack to force direct sampling mode to always be on if we set the remote-enabled bit in the EEPROM to 1. Default on EEPROM is 0. */
 	dev->force_ds = (buf[7] & 0x01) ? 1 : 0;
-	if(dev->force_ds) {
-		dev->tuner_type = RTLSDR_TUNER_UNKNOWN;
-		rtlsdr_set_direct_sampling(dev, 2);
-	}
-
 
 	if (dev->tuner->init)
 		r = dev->tuner->init(dev);
 
 	rtlsdr_set_i2c_repeater(dev, 0);
 
+	if(dev->force_ds) {
+		dev->tuner_type = RTLSDR_TUNER_UNKNOWN;
+		rtlsdr_set_direct_sampling(dev, 2);
+	}
+
 	*out_dev = dev;
 
 	return 0;
@@ -1918,7 +1918,7 @@ int rtlsdr_read_async(rtlsdr_dev_t *dev, rtlsdr_read_async_cb_t cb, void *ctx,
 		r = libusb_submit_transfer(dev->xfer[i]);
 		if (r < 0) {
 			fprintf(stderr, "Failed to submit transfer %i\n"
-					"Please increase your allowed " 
+					"Please increase your allowed "
 					"usbfs buffer size with the "
 					"following command:\n"
 					"echo 0 > /sys/module/usbcore"

Diff for: src/rtl_sdr.c

@@ -34,7 +34,7 @@
 #include "rtl-sdr.h"
 #include "convenience/convenience.h"
 
-#define DEFAULT_SAMPLE_RATE		2048000
+#define DEFAULT_SAMPLE_RATE		1500000
 #define DEFAULT_BUF_LENGTH		(16 * 16384)
 #define MINIMAL_BUF_LENGTH		512
 #define MAXIMAL_BUF_LENGTH		(256 * 16384)
@@ -48,13 +48,17 @@ void usage(void)
 	fprintf(stderr,
 		"rtl_sdr, an I/Q recorder for RTL2832 based DVB-T receivers\n\n"
 		"Usage:\t -f frequency_to_tune_to [Hz]\n"
-		"\t[-s samplerate (default: 2048000 Hz)]\n"
+		"\t[-s samplerate (default: 1500000 Hz)]\n"
 		"\t[-d device_index (default: 0)]\n"
 		"\t[-g gain (default: 0 for auto)]\n"
 		"\t[-p ppm_error (default: 0)]\n"
 		"\t[-b output_block_size (default: 16 * 16384)]\n"
 		"\t[-n number of samples to read (default: 0, infinite)]\n"
 		"\t[-S force sync output (default: async)]\n"
+		"\t[-E enable_option (default: none)]\n"
+		"\t[use multiple -E to enable multiple options]\n"
+		"\t[direct:  enable direct sampling 1 (usually I)]\n"
+		"\t[direct2: enable direct sampling 2 (usually Q)]\n"
 		"\tfilename (a '-' dumps samples to stdout)\n\n");
 	exit(1);
 }
@@ -113,15 +117,16 @@ int main(int argc, char **argv)
 	int gain = 0;
 	int ppm_error = 0;
 	int sync_mode = 0;
+	int direct_sampling = 0;
 	FILE *file;
 	uint8_t *buffer;
 	int dev_index = 0;
 	int dev_given = 0;
-	uint32_t frequency = 100000000;
+	uint32_t frequency = 1500000;
 	uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
 	uint32_t out_block_size = DEFAULT_BUF_LENGTH;
 
-	while ((opt = getopt(argc, argv, "d:f:g:s:b:n:p:S")) != -1) {
+	while ((opt = getopt(argc, argv, "d:f:g:s:b:n:p:S:E:")) != -1) {
 		switch (opt) {
 		case 'd':
 			dev_index = verbose_device_search(optarg);
@@ -148,6 +153,12 @@ int main(int argc, char **argv)
 		case 'S':
 			sync_mode = 1;
 			break;
+		case 'E':
+			if (strcmp("direct",  optarg) == 0) {
+				direct_sampling = 1;}
+			if (strcmp("direct2", optarg) == 0) {
+				direct_sampling = 2;}
+			break;
 		default:
 			usage();
 			break;
@@ -197,11 +208,6 @@ int main(int argc, char **argv)
 #else
 	SetConsoleCtrlHandler( (PHANDLER_ROUTINE) sighandler, TRUE );
 #endif
-	/* Set the sample rate */
-	verbose_set_sample_rate(dev, samp_rate);
-
-	/* Set the frequency */
-	verbose_set_frequency(dev, frequency);
 
 	if (0 == gain) {
 		 /* Enable automatic gain */
@@ -212,6 +218,15 @@ int main(int argc, char **argv)
 		verbose_gain_set(dev, gain);
 	}
 
+	if(direct_sampling)
+		verbose_direct_sampling(dev, direct_sampling);
+
+	/* Set the frequency */
+	verbose_set_frequency(dev, frequency);
+
+	/* Set the sample rate */
+	verbose_set_sample_rate(dev, samp_rate);
+
 	verbose_ppm_set(dev, ppm_error);
 
 	if(strcmp(filename, "-") == 0) { /* Write samples to stdout */