Prepare transmission code

Restructure/add some buffer code
Reset the watchdog timer (now at 1.5s), add a watchdog pinger thread


git-svn-id: https://svn.openpcd.org:2342/trunk@352 6dc7ffe9-61d6-0310-9af1-9938baff3ed1

8 files changed, 264 insertions, 111 deletions

diff --git a/openpicc/application/cmd.c b/openpicc/application/cmd.c
index 6e5230e..8c06a3d 100644
--- a/openpicc/application/cmd.c
+++ b/openpicc/application/cmd.c
@@ -26,6 +26,10 @@ xTaskHandle xCmdRecvUsbTask;
 xTaskHandle xFieldMeterTask;
 xSemaphoreHandle xFieldMeterMutex;
 
+#if ( configUSE_TRACE_FACILITY == 1 )
+static signed portCHAR pcWriteBuffer[512];
+#endif
+
 /* Whether to require a colon (':') be typed before long commands, similar to e.g. vi
  * This makes a distinction between long commands and short commands: long commands may be
  * longer than one character and/or accept optional parameters, short commands are only one
@@ -262,11 +266,6 @@ void prvExecCommand(u_int32_t cmd, portCHAR *args) {
 		    DumpStringToUSB(" * SSC_RCMR value: ");
 		    DumpUIntToUSB(*AT91C_SSC_RCMR);
 		    DumpStringToUSB("\n\r");
-		    DumpStringToUSB(" * is remapped?: ");
-		    DumpStringToUSB( (*(int*)0x00100100 == *(int*)0x00000100) ? "no" :
-		    	 ((*(int*)0x00200100 == *(int*)0x00000100) ? "yes" : "foo")
-		    );
-		    DumpStringToUSB("\n\r");
 		    DumpStringToUSB(
 			" *\n\r"
 			" *****************************************************\n\r"
@@ -300,6 +299,14 @@ void prvExecCommand(u_int32_t cmd, portCHAR *args) {
 		    break;
 		case 'F':
 		    startstop_field_meter();
+		    break;
+#if ( configUSE_TRACE_FACILITY == 1 )
+		case 'T':
+		    memset(pcWriteBuffer, 0, sizeof(pcWriteBuffer));
+		    vTaskList(pcWriteBuffer);
+		    DumpStringToUSB((char*)pcWriteBuffer);
+		    break;
+#endif
 		case 'Q':
 		    ssc_rx_start();
 		    while(0) {
@@ -320,6 +327,9 @@ void prvExecCommand(u_int32_t cmd, portCHAR *args) {
 			" *\n\r"
 			" * s    - store transmitter settings\n\r"
 			" * test - test critical sections\n\r"
+#if ( configUSE_TRACE_FACILITY == 1 )
+			" * t    - print task list and stack usage\n\r"
+#endif
 			" * c    - print configuration\n\r"
 			" * 0    - receive only mode\n\r"
 			" * 1..4 - automatic transmit at selected power levels\n\r"
@@ -479,12 +489,12 @@ portBASE_TYPE vCmdInit(void) {
 		return 0;
 	}
 	
-	if(xTaskCreate(vCmdRecvUsbCode, (signed portCHAR *)"CMDUSB", TASK_CMD_STACK, NULL, 
+	if(xTaskCreate(vCmdRecvUsbCode, (signed portCHAR *)"CMDUSB", 128, NULL, 
 		TASK_CMD_PRIORITY, &xCmdRecvUsbTask) != pdPASS) {
 		return 0;
 	}
 	
-	if(xTaskCreate(vFieldMeter, (signed portCHAR *)"FIELD METER", TASK_CMD_STACK, NULL, 
+	if(xTaskCreate(vFieldMeter, (signed portCHAR *)"FIELD METER", 128, NULL, 
 		TASK_CMD_PRIORITY, &xFieldMeterTask) != pdPASS) {
 		return 0;
 	}
diff --git a/openpicc/application/decoder.h b/openpicc/application/decoder.h
index bd25777..7892ea6 100644
--- a/openpicc/application/decoder.h
+++ b/openpicc/application/decoder.h
@@ -21,6 +21,7 @@ struct decoder_state {
 extern int decoder_register(int algnum, struct decoder_algo *algo);
 extern int decoder_decode(u_int8_t algo, const char *sample_buf,
 		  	  int sample_buf_size, unsigned char *data_buf);
+extern void decoder_init(void);
 
 #define DECODER_MILLER		0
 #define DECODER_NRZL		1
diff --git a/openpicc/application/iso14443_layer3a.c b/openpicc/application/iso14443_layer3a.c
index 841ad14..2239655 100644
--- a/openpicc/application/iso14443_layer3a.c
+++ b/openpicc/application/iso14443_layer3a.c
@@ -34,20 +34,34 @@
 #include "tc_cdiv_sync.h"
 #include "usb_print.h"
 #include "cmd.h"
+#include "load_modulation.h"
+#include "decoder.h"
+#include "iso14443a_manchester.h"
+#include "led.h"
 
 static enum ISO14443_STATES state = STARTING_UP;
+const iso14443_frame ATQA_FRAME = {
+	TYPE_A,
+	{{STANDARD_FRAME, NO_PARITY}},
+	2, 
+	0, 0,
+	{4, 0},
+	{}
+};
+
+
 #define PLL_LOCK_HYSTERESIS portTICK_RATE_MS*5
 
 #define LAYER3_DEBUG usb_print_string
 
-extern void main_help_print_buffer(ssc_dma_buffer_t *buffer, int *pktcount);
+extern void main_help_print_buffer(ssc_dma_rx_buffer_t *buffer, int *pktcount);
 void iso14443_layer3a_state_machine (void *pvParameters)
 {
 	unsigned long int last_pll_lock = ~0;
 	int pktcount=0;
 	(void)pvParameters;
 	while(1) {
-		ssc_dma_buffer_t* buffer = NULL;
+		ssc_dma_rx_buffer_t* buffer = NULL;
 		portBASE_TYPE need_receive = 0, switch_on = 0;
 		
 		/* First let's see whether there is a reader */
@@ -97,7 +111,7 @@ void iso14443_layer3a_state_machine (void *pvParameters)
 				tc_cdiv_set_divider(64);
 #endif
 				tc_fdt_init();
-#if 0
+#if 1
 				ssc_tx_init();
 #else
 				AT91F_PIO_CfgInput(AT91C_BASE_PIOA, OPENPICC_MOD_PWM);
@@ -107,6 +121,10 @@ void iso14443_layer3a_state_machine (void *pvParameters)
 #endif
 				ssc_rx_init();
 				
+				load_mod_init();
+				load_mod_level(3);
+				
+				
 				state = POWERED_OFF;
 				break;
 			case POWERED_OFF:
@@ -127,6 +145,7 @@ void iso14443_layer3a_state_machine (void *pvParameters)
 		
 		if(need_receive) {
 			if(xQueueReceive(ssc_rx_queue, &buffer, portTICK_RATE_MS)) {
+				vLedSetGreen(0);
 				portENTER_CRITICAL();
 				buffer->state = PROCESSING;
 				portEXIT_CRITICAL();
@@ -145,6 +164,36 @@ void iso14443_layer3a_state_machine (void *pvParameters)
 							LAYER3_DEBUG("Received ");
 							LAYER3_DEBUG(first_sample == WUPA ? "WUPA" : "REQA");
 							LAYER3_DEBUG(" waking up to send ATQA\n\r");
+							portENTER_CRITICAL();
+							if(ssc_tx_buffer.state != FREE) {
+								portEXIT_CRITICAL();
+								/* Wait for another frame */
+								ssc_rx_mode_set(SSC_MODE_14443A_SHORT);
+								ssc_rx_start();
+							} else {
+								ssc_tx_buffer.state = PROCESSING;
+								portEXIT_CRITICAL();
+								ssc_tx_buffer.len = sizeof(ssc_tx_buffer.data);
+								unsigned int ret = 
+									manchester_encode(ssc_tx_buffer.data,
+										ssc_tx_buffer.len,
+										&ATQA_FRAME);
+								if(ret>0) {
+									ssc_tx_buffer.len = ret;
+									LAYER3_DEBUG("Buffer ");
+									DumpUIntToUSB(ret);
+									LAYER3_DEBUG(" ");
+									DumpBufferToUSB((char*)ssc_tx_buffer.data, ssc_tx_buffer.len);
+									LAYER3_DEBUG("\n\r");
+								} else {
+									portENTER_CRITICAL();
+									ssc_tx_buffer.state = FREE;
+									portEXIT_CRITICAL();
+									/* Wait for another frame */
+									ssc_rx_mode_set(SSC_MODE_14443A_SHORT);
+									ssc_rx_start();
+								}
+							}
 						} else {
 							/* Wait for another frame */
 							ssc_rx_mode_set(SSC_MODE_14443A_SHORT);
diff --git a/openpicc/application/iso14443_layer3a.h b/openpicc/application/iso14443_layer3a.h
index 6f32dd5..142128e 100644
--- a/openpicc/application/iso14443_layer3a.h
+++ b/openpicc/application/iso14443_layer3a.h
@@ -15,6 +15,7 @@ enum ISO14443_STATES {
 	ERROR,       /* Some unrecoverable error has occured */
 };
 
+/******************** RX ************************************/
 /* standard derived magic values */
 #define ISO14443A_FDT_SHORT_1	1236
 #define ISO14443A_FDT_SHORT_0	1172
@@ -30,6 +31,15 @@ enum ISO14443_STATES {
 #define ISO14443A_SOF_LEN	4
 /* Length in samples of a short frame */
 #define ISO14443A_SHORT_LEN     32
+/* This is wrong: a short frame is 1 start bit, 7 data bits, 1 stop bit 
+ * followed by no modulation for one bit period. The start bit is 'eaten' in 
+ * SSC Compare 0, but the remaining 7+1+1 bit durations must be sampled and
+ * compared. At four times oversampling this would be 9*4=36 samples, which is 
+ * more than one SSC transfer. You'd have to use two transfers of 18 samples
+ * each and modify the comparison code accordingly. 
+ * Since four times oversampling doesn't work reliably anyway (every second
+ * sample is near an edge and might sample 0 or 1) this doesn't matter for now.*/
+#error Four times oversampling is broken, see comments in code 
 
 #else
 /* definitions for two-times oversampling */
@@ -38,8 +48,49 @@ enum ISO14443_STATES {
 
 #define ISO14443A_SOF_SAMPLE	0x01
 #define ISO14443A_SOF_LEN	2
-#define ISO14443A_SHORT_LEN     16
+#define ISO14443A_SHORT_LEN     18
 
 #endif
 
+/* A short frame should be received in one single SSC transfer */
+#if (ISO14443A_SHORT_LEN <= 8)
+/* SSC transfer size in bits */
+#define ISO14443A_SHORT_TRANSFER_SIZE 8
+#define ISO14443A_SHORT_TYPE u_int8_t
+
+#elif (ISO14443A_SHORT_LEN <= 16)
+#define ISO14443A_SHORT_TRANSFER_SIZE 16
+#define ISO14443A_SHORT_TYPE u_int16_t
+
+#elif (ISO14443A_SHORT_LEN <= 32)
+#define ISO14443A_SHORT_TRANSFER_SIZE 32
+#define ISO14443A_SHORT_TYPE u_int32_t
+
+#else
+#error ISO14443A_SHORT_LEN defined too big
+#endif
+
+/******************** TX ************************************/
+/* in bytes, not counting parity */
+#define MAXIMUM_FRAME_SIZE 256
+
+typedef struct {
+  enum { TYPE_A, TYPE_B } type;
+  union {
+  	struct {
+  		enum { SHORT_FRAME, STANDARD_FRAME, AC_FRAME } format;
+  		enum { PARITY, /* Calculate parity on the fly, ignore the parity field below */ 
+  		       GIVEN_PARITY, /* Use the parity bits from the parity field below */  
+  		       NO_PARITY, /* Don't send any parity */
+  		} parity; 
+  	} a;
+  } parameters;
+  u_int32_t numbytes;
+  u_int8_t numbits, bit_offset;
+  u_int8_t data[MAXIMUM_FRAME_SIZE];
+  u_int8_t parity[MAXIMUM_FRAME_SIZE]; /* Only the LSB of each byte is used */
+} iso14443_frame;
+
+extern const iso14443_frame ATQA_FRAME;
+
 #endif /*ISO14443_LAYER3A_H_*/
diff --git a/openpicc/application/iso14443a_manchester.c b/openpicc/application/iso14443a_manchester.c
index efc4baf..eff5a31 100644
--- a/openpicc/application/iso14443a_manchester.c
+++ b/openpicc/application/iso14443a_manchester.c
@@ -25,7 +25,7 @@
  * 		MSB first		LSB first	hex LSB first
  * Sequence D	1010101000000000	0000000001010101	0x0055
  * Sequence E	0000000010101010	0101010100000000	0x5500
- * Sequence F	1010101010101010	0101010101010101	0x5555
+ * Sequence F	0000000000000000	0000000000000000	0x0000
  *
  * Logic 1	Sequence D
  * Logic 0	Sequence E
@@ -44,79 +44,93 @@
 
 #define MANCHESTER_SEQ_D	0x0055
 #define MANCHESTER_SEQ_E	0x5500
-#define MANCHESTER_SEQ_F	0x5555
+#define MANCHESTER_SEQ_F	0x0000
 
 #include <errno.h>
 #include <string.h>
 #include "openpicc.h"
+#include "iso14443_layer3a.h"
+#include "iso14443a_manchester.h"
 
-static u_int32_t manchester_sample_size(u_int8_t frame_bytelen) __attribute__((unused));
-static u_int32_t manchester_sample_size(u_int8_t frame_bytelen)
-{
-	/* 16 bits (2 bytes) per bit => 16 bytes samples per data byte,
-	 * plus 16bit (2 bytes) parity per data byte
-	 * plus 16bit (2 bytes) SOF plus 16bit (2 bytes) EOF */
-	return (frame_bytelen*18) + 2 + 2;
-
-	/* this results in a maximum samples-per-frame size of 4612 bytes
-	 * for a 256byte frame */
-}
-
-struct manch_enc_state {
-	const char *data;
-	char *samples;
-	u_int16_t *samples16;
+enum parity {
+	PARITY_NONE, /* Don't add a parity bit */
+	ODD_PARITY, EVEN_PARITY, /* Calculate parity */
+	PARITY_0, PARITY_1 /* Set fixed parity */
 };
 
-static void manchester_enc_byte(struct manch_enc_state *mencs, u_int8_t data) __attribute__((unused));
-static void manchester_enc_byte(struct manch_enc_state *mencs, u_int8_t data)
+static void manchester_enc_byte(u_int16_t **s16, u_int8_t data, enum parity parity)
 {
 	int i;
 	u_int8_t sum_1 = 0;
+	u_int16_t *samples16 = *s16;
 
 	/* append 8 sample blobs, one for each bit */
 	for (i = 0; i < 8; i++) {
 		if (data & (1 << i)) {
-			*(mencs->samples16) = MANCHESTER_SEQ_D;
+			*(samples16) = MANCHESTER_SEQ_D;
 			sum_1++;
 		} else {
-			*(mencs->samples16) = MANCHESTER_SEQ_E;
+			*(samples16) = MANCHESTER_SEQ_E;
+		}
+		samples16++;
+	}
+	if(parity != PARITY_NONE) {
+		/* Append parity */
+		u_int8_t par=0;
+		switch(parity) {
+			case PARITY_NONE: break;
+			case PARITY_0: par = 0; break;
+			case PARITY_1: par = 1; break;
+			case ODD_PARITY:  par = (sum_1 & 0x1) ? 0 : 1; break;
+			case EVEN_PARITY: par = (sum_1 & 0x1) ? 1 : 0; break;
 		}
-		mencs->samples16++;
+		if (par)
+			*(samples16) = MANCHESTER_SEQ_D;
+		else
+			*(samples16) = MANCHESTER_SEQ_E;
+		samples16++;
 	}
-	/* append odd parity */
-	if (sum_1 & 0x01)
-		*(mencs->samples16) = MANCHESTER_SEQ_E;
-	else
-		*(mencs->samples16) = MANCHESTER_SEQ_D;
-	mencs->samples16++;
+	*s16 = samples16;
 }
 
-#if 0
-/* Broken? */
-int manchester_encode(char *sample_buf, u_int16_t sample_buf_len, 
-		      const char *data, u_int8_t data_len)
+int manchester_encode(u_int8_t *sample_buf, u_int16_t sample_buf_len, 
+		      const iso14443_frame *frame)
 {
-	int i, enc_size;
-	struct manch_enc_state mencs;
-
-	enc_size = manchester_sample_size(data_len);
+	unsigned int i, enc_size;
+	u_int16_t *samples16;
+	
+	if(frame->type != TYPE_A) return -EINVAL;
+	if(frame->parameters.a.format != STANDARD_FRAME) return -EINVAL; /* AC not implemented yet */
+	
+	/* One bit data is 16 bit/2 byte modulation data */
+	enc_size = 2*2 /* SOF and EOF */
+		+ frame->numbytes * 8 * 2
+		+ ((frame->parameters.a.parity != NO_PARITY) ? 1 : 0)*8*2;
 
 	if (sample_buf_len < enc_size)
 		return -EINVAL;
+	
+	samples16 = (u_int16_t*)sample_buf;
 
 	/* SOF */
-	*(mencs.samples16++) = MANCHESTER_SEQ_D;
-
-	for (i = 0; i < data_len; i++)
-		manchester_enc_byte(&mencs, data[i]);
+	*(samples16++) = MANCHESTER_SEQ_D;
+	
+	if(frame->parameters.a.parity == NO_PARITY)
+		for (i = 0; i < frame->numbytes; i++)
+			manchester_enc_byte(&samples16, frame->data[i], PARITY_NONE);
+	else if(frame->parameters.a.parity == GIVEN_PARITY)
+		for (i = 0; i < frame->numbytes; i++)
+			manchester_enc_byte(&samples16, frame->data[i], frame->parity[i]?PARITY_1:PARITY_0);
+	else if(frame->parameters.a.parity == PARITY)
+		for (i = 0; i < frame->numbytes; i++)
+			manchester_enc_byte(&samples16, frame->data[i], ODD_PARITY);
 		
 	/* EOF */
-	*(mencs.samples16++) = MANCHESTER_SEQ_F;
+	*(samples16++) = MANCHESTER_SEQ_F;
 
 	return enc_size;
 }
-#endif
+
 #if 0
 /* Broken? */
 #define BPSK_SPEED_212	
diff --git a/openpicc/application/main.c b/openpicc/application/main.c
index 48e9ab2..a093d70 100644
--- a/openpicc/application/main.c
+++ b/openpicc/application/main.c
@@ -48,6 +48,7 @@
 #include "tc_fdt.h"
 #include "usb_print.h"
 #include "iso14443_layer3a.h"
+#include "decoder.h"
 
 /**********************************************************************/
 static inline void prvSetupHardware (void)
@@ -76,8 +77,6 @@ void vApplicationIdleHook(void)
 {
     static char disabled_green = 0;
     //static int i=0;
-    /* Restart watchdog, has been enabled in Cstartup_SAM7.c */
-    AT91F_WDTRestart(AT91C_BASE_WDTC);
     //vLedSetGreen(i^=1);
     if(!disabled_green) {
     	//vLedSetGreen(0);
@@ -86,9 +85,9 @@ void vApplicationIdleHook(void)
     usb_print_flush();
 }
 
-void main_help_print_buffer(ssc_dma_buffer_t *buffer, int *pktcount)
+void main_help_print_buffer(ssc_dma_rx_buffer_t *buffer, int *pktcount)
 {
-	u_int16_t *tmp = (u_int16_t*)buffer->data;
+	ISO14443A_SHORT_TYPE *tmp = (ISO14443A_SHORT_TYPE*)buffer->data;
 	int i, dumped = 0;
 	unsigned int j;
 	for(i = buffer->len / sizeof(*tmp); i >= 0 ; i--) {
@@ -102,7 +101,7 @@ void main_help_print_buffer(ssc_dma_buffer_t *buffer, int *pktcount)
 				DumpStringToUSB(" ");
 			}
 			dumped = 1;
-			DumpUIntToUSB(i);
+			DumpUIntToUSB(buffer->len / sizeof(*tmp) - i);
 			DumpStringToUSB(": ");
 			for(j=0; j<sizeof(*tmp)*8; j++) {
 				usb_print_char_f( (((*tmp) >> j) & 0x1) ? '1' : '_' , 0);
@@ -120,7 +119,7 @@ void vMainTestSSCRXConsumer (void *pvParameters)
 	static int pktcount=0;
 	(void)pvParameters;
 	while(1) {
-		ssc_dma_buffer_t* buffer;
+		ssc_dma_rx_buffer_t* buffer;
 		if(xQueueReceive(ssc_rx_queue, &buffer, portMAX_DELAY)) {
 			portENTER_CRITICAL();
 			buffer->state = PROCESSING;
@@ -142,11 +141,25 @@ void vMainTestSSCRXConsumer (void *pvParameters)
 	}
 }
 
+/* This task pings the watchdog even when the idle task is not running
+ * It should be started with a very high priority and will delay most of the time */
+void vMainWatchdogPinger (void *pvParameters)
+{
+	(void)pvParameters;
+    
+	while(1) {
+		/* Restart watchdog, has been enabled in Cstartup_SAM7.c */
+    		AT91F_WDTRestart(AT91C_BASE_WDTC);
+    		vTaskDelay(500*portTICK_RATE_MS);
+	}
+}
+
 /**********************************************************************/
 int main (void)
 {
     prvSetupHardware ();
     usb_print_init();
+    decoder_init();
     
     pio_irq_init();
     
@@ -165,6 +178,9 @@ int main (void)
 	
     vCmdInit();
     
+    xTaskCreate (vMainWatchdogPinger, (signed portCHAR *) "WDT PINGER", 64,
+	NULL, TASK_ISO_PRIORITY -1, NULL);
+	
     //vLedSetGreen(1);
     
     /* Remap RAM to addr 0 */
diff --git a/openpicc/application/ssc_picc.c b/openpicc/application/ssc_picc.c
index e9fdbfb..19f028e 100644
--- a/openpicc/application/ssc_picc.c
+++ b/openpicc/application/ssc_picc.c
@@ -52,16 +52,18 @@
 static const AT91PS_SSC ssc = AT91C_BASE_SSC;
 static AT91PS_PDC rx_pdc;
 
-static ssc_dma_buffer_t dma_buffers[SSC_DMA_BUFFER_COUNT];
+static ssc_dma_rx_buffer_t dma_buffers[SSC_DMA_BUFFER_COUNT];
 xQueueHandle ssc_rx_queue = NULL;
 
+ssc_dma_tx_buffer_t ssc_tx_buffer;
+
 #define TEST_WHETHER_NOT_ENABLING_IT_HELPS
 #define TEST_WHETHER_THIS_INTERRUPT_WORKS_AT_ALL
 
-static ssc_dma_buffer_t* __ramfunc ssc_find_dma_buffer(ssc_dma_buffer_state_t oldstate, 
+static ssc_dma_rx_buffer_t* __ramfunc ssc_find_dma_buffer(ssc_dma_buffer_state_t oldstate, 
 	ssc_dma_buffer_state_t newstate)
 {
-	ssc_dma_buffer_t* result = NULL; 
+	ssc_dma_rx_buffer_t* result = NULL; 
 	int i=0;
 	for(i=0; i<SSC_DMA_BUFFER_COUNT; i++) {
 		if(dma_buffers[i].state == oldstate) {
@@ -74,18 +76,18 @@ static ssc_dma_buffer_t* __ramfunc ssc_find_dma_buffer(ssc_dma_buffer_state_t ol
 }
 
 struct ssc_state {
-	ssc_dma_buffer_t* buffer[2];
+	ssc_dma_rx_buffer_t* buffer[2];
 	enum ssc_mode mode;
 };
 static struct ssc_state ssc_state;
 
-static const u_int16_t ssc_dmasize[] = {
-	[SSC_MODE_NONE]			= 16,
-	[SSC_MODE_14443A_SHORT]		= 16,	/* 64 bytes */
-	[SSC_MODE_14443A_STANDARD]	= 16,	/* 64 bytes */
-	[SSC_MODE_14443B]		= 16,	/* 64 bytes */
-	[SSC_MODE_EDGE_ONE_SHOT] 	= 16,	/* 64 bytes */
-	[SSC_MODE_CONTINUOUS]		= 511,	/* 2044 bytes */
+static const struct {u_int16_t bytes; u_int16_t transfers;} ssc_dmasize[] = {
+	[SSC_MODE_NONE]			= {0, 0},
+	[SSC_MODE_14443A_SHORT]		= {ISO14443A_SHORT_TRANSFER_SIZE/8, 1},	/* 1 transfer of ISO14443A_SHORT_LEN bits */
+	[SSC_MODE_14443A_STANDARD]	= {16*4, 16},	/* 64 bytes */
+	[SSC_MODE_14443B]		= {16*4, 16},	/* 64 bytes */
+	[SSC_MODE_EDGE_ONE_SHOT] 	= {16*4, 16},	/* 64 bytes */
+	[SSC_MODE_CONTINUOUS]		= {511*4, 511},	/* 2044 bytes */
 };
 
 #define SSC_RX_IRQ_MASK	(AT91C_SSC_RXRDY | 	\
@@ -117,7 +119,7 @@ void ssc_rx_mode_set(enum ssc_mode ssc_mode)
 		sync_len = ISO14443A_SOF_LEN;
 		ssc->SSC_RC0R = ISO14443A_SOF_SAMPLE;
 		data_len = ISO14443A_SHORT_LEN;
-		num_data = 16;
+		num_data = 2;
 		break;
 	case SSC_MODE_14443A_STANDARD:
 		start_cond = AT91C_SSC_START_0;
@@ -159,9 +161,9 @@ void ssc_rx_mode_set(enum ssc_mode ssc_mode)
 
 	/* Enable RX interrupts */
 #ifdef TEST_WHETHER_NOT_ENABLING_IT_HELPS
-
+/*
 	AT91F_SSC_EnableIt(ssc, AT91C_SSC_OVRUN | AT91C_SSC_CP0 |
-			   AT91C_SSC_ENDRX | AT91C_SSC_RXBUFF);
+			   AT91C_SSC_ENDRX | AT91C_SSC_RXBUFF);*/
 #endif
 out_set_mode:
 	ssc_state.mode = ssc_mode;
@@ -249,7 +251,7 @@ int ssc_count_free(void) {
 
 static int __ramfunc __ssc_rx_refill(int secondary)
 {
-	ssc_dma_buffer_t *buffer;
+	ssc_dma_rx_buffer_t *buffer;
 	
 	buffer = ssc_find_dma_buffer(FREE, PENDING);
 	if (!buffer) {
@@ -260,14 +262,14 @@ static int __ramfunc __ssc_rx_refill(int secondary)
 	//init_opcdhdr(buffer);
 	DEBUGR("filling SSC RX%u dma ctx: %u (len=%u) ", secondary,
 		req_ctx_num(buffer), buffer->size);
-	buffer->len = ssc_dmasize[ssc_state.mode]*4;
+	buffer->len = ssc_dmasize[ssc_state.mode].bytes;
 	if (secondary) {
 		AT91F_PDC_SetNextRx(rx_pdc, buffer->data,
-				    ssc_dmasize[ssc_state.mode]);
+				    ssc_dmasize[ssc_state.mode].transfers);
 		ssc_state.buffer[1] = buffer;
 	} else {
 		AT91F_PDC_SetRx(rx_pdc, buffer->data,
-				ssc_dmasize[ssc_state.mode]);
+				ssc_dmasize[ssc_state.mode].transfers);
 		ssc_state.buffer[0] = buffer;
 	}
 
@@ -360,9 +362,10 @@ static void __ramfunc ssc_irq(void)
 		/* in a one-shot sample, we don't want to keep
 		 * sampling further after having received the first
 		 * packet.  */
-		if (ssc_state.mode == SSC_MODE_EDGE_ONE_SHOT) {
+		if (ssc_state.mode == SSC_MODE_EDGE_ONE_SHOT || ssc_state.mode == SSC_MODE_14443A_SHORT) {
 			DEBUGP("DISABLE_RX ");
 			ssc_rx_stop();
+			vLedSetGreen(1);
 		}
 		//AT91F_SSC_DisableIt(AT91C_BASE_SSC, SSC_RX_IRQ_MASK);
 #endif
@@ -389,12 +392,6 @@ static void __ramfunc ssc_irq(void)
 			ssc_state.buffer[0]->state = FULL;
 			//gaportEXIT_CRITICAL();
 			task_woken = xQueueSendFromISR(ssc_rx_queue, &ssc_state.buffer[0], task_woken);
-			/*vLedBlinkRed();
-			vLedSetRed(1); for(i=0; i<50; i++) (void)i; vLedSetRed(0); 
-			for(i=0; i<ssc_state.buffer[0]->len*8; i++) {
-				vLedSetRed( ssc_state.buffer[0]->data[i/8] & (1<<(i%8)) );
-			}
-			vLedBlinkRed();*/
 		} else {
 			DEBUGP("EMPTY");
 			//gaportENTER_CRITICAL();
@@ -405,30 +402,28 @@ static void __ramfunc ssc_irq(void)
 		/* second buffer gets propagated to primary */
 		ssc_state.buffer[0] = ssc_state.buffer[1];
 		ssc_state.buffer[1] = NULL;
-		if (ssc_sr & AT91C_SSC_RXBUFF) {
-// FIXME
-			DEBUGP("RXBUFF! ");
-			if (ssc_state.buffer[0]) {
-				//DEBUGP("Sending secondary RCTX(%u, len=%u) ", req_ctx_num(ssc_state.rx_ctx[0]), ssc_state.rx_ctx[0]->tot_len);
-				//gaportENTER_CRITICAL();
-				ssc_state.buffer[0]->state = FULL;
-				//gaportEXIT_CRITICAL();
-				task_woken = xQueueSendFromISR(ssc_rx_queue, &ssc_state.buffer[0], task_woken);
+		if(ssc_state.mode != SSC_MODE_14443A_SHORT) {
+			if (ssc_sr & AT91C_SSC_RXBUFF) {
+	// FIXME
+				DEBUGP("RXBUFF! ");
+				if (ssc_state.buffer[0]) {
+					//DEBUGP("Sending secondary RCTX(%u, len=%u) ", req_ctx_num(ssc_state.rx_ctx[0]), ssc_state.rx_ctx[0]->tot_len);
+					//gaportENTER_CRITICAL();
+					ssc_state.buffer[0]->state = FULL;
+					//gaportEXIT_CRITICAL();
+					task_woken = xQueueSendFromISR(ssc_rx_queue, &ssc_state.buffer[0], task_woken);
+				}
+				if (__ssc_rx_refill(0) == -1)
+					AT91F_SSC_DisableIt(ssc, AT91C_SSC_ENDRX |
+							    AT91C_SSC_RXBUFF |
+							    AT91C_SSC_OVRUN);
 			}
-			if (__ssc_rx_refill(0) == -1)
+	
+			if (__ssc_rx_refill(1) == -1)
 				AT91F_SSC_DisableIt(ssc, AT91C_SSC_ENDRX |
 						    AT91C_SSC_RXBUFF |
 						    AT91C_SSC_OVRUN);
-		}
-
-		if (__ssc_rx_refill(1) == -1)
-			AT91F_SSC_DisableIt(ssc, AT91C_SSC_ENDRX |
-					    AT91C_SSC_RXBUFF |
-					    AT91C_SSC_OVRUN);
-
-//		udp_refill_ep(2);
-		
-		if(ssc_state.mode == SSC_MODE_14443A_SHORT) {
+		} else {
 			// Stop sampling here
 			ssc_rx_stop();
 		}
@@ -503,8 +498,11 @@ void ssc_rx_unthrottle(void)
 
 void ssc_rx_start(void)
 {
-	//DEBUGPCRF("starting SSC RX\n");	
-
+	//DEBUGPCRF("starting SSC RX\n");
+	
+	__ssc_rx_refill(0);
+	if(ssc_state.mode != SSC_MODE_14443A_SHORT) __ssc_rx_refill(1);
+	
 	/* Enable Reception */
 #ifdef TEST_WHETHER_NOT_ENABLING_IT_HELPS
 	AT91F_SSC_EnableIt(ssc, AT91C_SSC_ENDRX | AT91C_SSC_CP0 |
@@ -596,9 +594,8 @@ void ssc_rx_init(void)
 #endif
 	
 	ssc_rx_mode_set(SSC_MODE_NONE);
+	ssc_state.buffer[0] = ssc_state.buffer[1] = NULL;
 	
-	__ssc_rx_refill(0);
-	__ssc_rx_refill(1);
 #if 0
 	AT91F_PDC_EnableRx(rx_pdc);
 
diff --git a/openpicc/application/ssc_picc.h b/openpicc/application/ssc_picc.h
index 813ef33..db3cc00 100644
--- a/openpicc/application/ssc_picc.h
+++ b/openpicc/application/ssc_picc.h
@@ -2,6 +2,7 @@
 #define _SSC_H
 
 #include "queue.h"
+#include "iso14443_layer3a.h"
 
 extern void ssc_rx_start(void);
 extern void ssc_rx_stop(void);
@@ -29,7 +30,7 @@ extern portBASE_TYPE ssc_get_overflows(void);
 extern int ssc_count_free(void);
 
 #define SSC_DMA_BUFFER_SIZE 2048
-#define SSC_DMA_BUFFER_COUNT 10
+#define SSC_DMA_BUFFER_COUNT 4
 
 typedef enum {
 	FREE=0,    /* Buffer is free */
@@ -43,8 +44,22 @@ typedef struct {
 	u_int32_t len;  /* Length of the content */
 	enum ssc_mode reception_mode;
 	u_int8_t data[SSC_DMA_BUFFER_SIZE];
-} ssc_dma_buffer_t;
+} ssc_dma_rx_buffer_t;
 
 extern xQueueHandle ssc_rx_queue;
 
+/* in bytes, used for the sample buffer that holds the subcarrier modulation data at fc/8 = 1695 MHz */
+#define SSC_TX_BUFFER_SIZE ((MAXIMUM_FRAME_SIZE*( (8+1)*2 ) ) + 2 + 2)
+
+typedef struct {
+	volatile ssc_dma_buffer_state_t state;
+	u_int32_t len;  /* Length of the content */
+	u_int8_t data[SSC_TX_BUFFER_SIZE];
+} ssc_dma_tx_buffer_t;
+
+/* Declare one TX buffer. This means that only one buffer can ever be pending for sending. That's because
+ * this buffer must be huge (one frame of 256 bytes of subcarrier modulation data at  1695 MHz sample
+ * rate is approx 4k bytes). */
+extern ssc_dma_tx_buffer_t ssc_tx_buffer;
+
 #endif