Several modifications to enable spinning until the correct phase is reached in tc_fdt (thereby taking the phase information from tc_fdt, resetting the phase in tc_cdiv)

Still too much jitter (some bug in this code?)


git-svn-id: https://svn.openpcd.org:2342/trunk@383 6dc7ffe9-61d6-0310-9af1-9938baff3ed1

5 files changed, 53 insertions, 18 deletions

diff --git a/openpicc/application/iso14443_layer3a.c b/openpicc/application/iso14443_layer3a.c
index c4e02cd..0b5ceaf 100644
--- a/openpicc/application/iso14443_layer3a.c
+++ b/openpicc/application/iso14443_layer3a.c
@@ -74,20 +74,43 @@ const iso14443_frame NULL_FRAME = {
 #define INITIAL_FRAME NULL_FRAME
 #endif
 
+#define ISO14443A_TRANSMIT_AT_NEXT_INTERVAL_0 -1
+#define ISO14443A_TRANSMIT_AT_NEXT_INTERVAL_1 -2
+
+/* Transmit a frame in ISO14443A mode from buffer buf at fdt carrier cycles
+ * after the end of the last modulation pause from the PCD with a clock divisor
+ * of div. Set fdt to ISO14443A_TRANSMIT_AT_NEXT_INTERVAL_0 or _1 to have the 
+ * transmission start at the next possible interval. Use _0 when the last bit
+ * from the PCD was a 0 and _1 when it was a 1. */ 
+void iso14443_transmit(ssc_dma_tx_buffer_t *buf, int fdt, int div)
+{
+	tc_cdiv_set_divider(div);
+	if(fdt == ISO14443A_TRANSMIT_AT_NEXT_INTERVAL_0 ||
+		fdt == ISO14443A_TRANSMIT_AT_NEXT_INTERVAL_1) {
+			/* FIXME Implement */
+			return;
+		}
+	ssc_tx_fiq_fdt_cdiv = fdt -3*div -1;
+	tc_fdt_set(ssc_tx_fiq_fdt_cdiv -MAX_TF_FIQ_ENTRY_DELAY -MAX_TF_FIQ_OVERHEAD);
+	ssc_tx_fiq_fdt_ssc  = fdt -div +1;
+	ssc_tx_start(buf);
+}
+
 static int atqa_sent = 0;
 /* Running in ISR mode */
 void __ramfunc iso14443_layer3a_irq_ext(u_int32_t ssc_sr, enum ssc_mode ssc_mode, u_int8_t* samples)
 {
 	(void)ssc_sr;
+	int fdt;
 	if(ssc_mode == SSC_MODE_14443A_SHORT && samples) {
 		ISO14443A_SHORT_TYPE sample =  *(ISO14443A_SHORT_TYPE*)samples;
 		portBASE_TYPE send_atqa = 0;
 		if(sample == REQA) {
-			tc_fdt_set(ISO14443A_FDT_SHORT_0);
+			fdt = ISO14443A_FDT_SHORT_0;
 			if(state == IDLE)
 				send_atqa = 1;
 		} else if(sample == WUPA) {
-			tc_fdt_set(ISO14443A_FDT_SHORT_1);
+			fdt = ISO14443A_FDT_SHORT_1;
 			if(state == IDLE || state == HALT)
 				send_atqa = 1;
 		}
@@ -97,13 +120,13 @@ void __ramfunc iso14443_layer3a_irq_ext(u_int32_t ssc_sr, enum ssc_mode ssc_mode
 			if(ssc_tx_buffer.state == PREFILLED && ssc_tx_buffer.source == &ATQA_FRAME) {
 				ssc_tx_buffer.state = PROCESSING;
 				vLedSetGreen(1);
-				tc_cdiv_set_divider(8);
-				ssc_tx_start(&ssc_tx_buffer);
+				iso14443_transmit(&ssc_tx_buffer, fdt, 8);
 				atqa_sent = 1;
 				vLedSetGreen(0);
 			}
 		vLedSetGreen(1);
 		}
+		vLedSetGreen(0);
 	}
 }
 
@@ -142,7 +165,7 @@ static int prefill_buffer(ssc_dma_tx_buffer_t *dest, const iso14443_frame *src)
 static u_int8_t received_buffer[256];
 
 static void enable_reception(enum ssc_mode mode) {
-	tc_fdt_set(ISO14443A_FDT_SHORT_0);
+	tc_fdt_set(0xff00);
 	ssc_rx_mode_set(mode);
 #ifdef FOUR_TIMES_OVERSAMPLING
 	tc_cdiv_set_divider(32);
@@ -313,9 +336,7 @@ void iso14443_layer3a_state_machine (void *pvParameters)
 								if(prefill_buffer(&ssc_tx_buffer, &NULL_FRAME)) {
 									usb_print_string_f("Sending response ...",0);
 									ssc_tx_buffer.state = PROCESSING;
-									tc_cdiv_set_divider(8);
-									tc_fdt_set_to_next_slot(1);
-									ssc_tx_start(&ssc_tx_buffer);
+									iso14443_transmit(&ssc_tx_buffer, 1, 8);
 									while( ssc_tx_buffer.state != FREE ) {
 										vTaskDelay(portTICK_RATE_MS);
 									}
diff --git a/openpicc/application/iso14443_layer3a.h b/openpicc/application/iso14443_layer3a.h
index 0c2a909..b71c13f 100644
--- a/openpicc/application/iso14443_layer3a.h
+++ b/openpicc/application/iso14443_layer3a.h
@@ -16,17 +16,18 @@ enum ISO14443_STATES {
 };
 
 /******************** RX ************************************/
-/* measured TF->FIQ->SSC TX start delay (~3.480us) in carrier cycles */
-#define TF_FIQ_SSC_DELAY 47
-//#define TF_FIQ_SSC_DELAY 40
-#define FALLING_EDGE_DETECTION_DELAY 12
+/* Magic delay, don't know where it comes from */
+#define MAGIC_DELAY -32
+/* See fdt_timinig.dia for these values */
+#define MAX_TF_FIQ_ENTRY_DELAY 16
+#define MAX_TF_FIQ_OVERHEAD 75 /* guesstimate */ 
 extern volatile int fdt_offset;
 /* standard derived magic values */
 #define ISO14443A_FDT_SLOTLEN 128
 #define ISO14443A_FDT_OFFSET_1 84
 #define ISO14443A_FDT_OFFSET_0 20
-#define ISO14443A_FDT_SHORT_1	(ISO14443A_FDT_SLOTLEN*9 + ISO14443A_FDT_OFFSET_1 -FALLING_EDGE_DETECTION_DELAY +fdt_offset -TF_FIQ_SSC_DELAY)
-#define ISO14443A_FDT_SHORT_0	(ISO14443A_FDT_SLOTLEN*9 + ISO14443A_FDT_OFFSET_0 -FALLING_EDGE_DETECTION_DELAY +fdt_offset -TF_FIQ_SSC_DELAY)
+#define ISO14443A_FDT_SHORT_1	(ISO14443A_FDT_SLOTLEN*9 + ISO14443A_FDT_OFFSET_1 +fdt_offset +MAGIC_DELAY)
+#define ISO14443A_FDT_SHORT_0	(ISO14443A_FDT_SLOTLEN*9 + ISO14443A_FDT_OFFSET_0 +fdt_offset +MAGIC_DELAY)
 
 #ifdef FOUR_TIMES_OVERSAMPLING
 /* definitions for four-times oversampling */
diff --git a/openpicc/application/ssc_picc.c b/openpicc/application/ssc_picc.c
index 10beaab..3da1dbe 100644
--- a/openpicc/application/ssc_picc.c
+++ b/openpicc/application/ssc_picc.c
@@ -302,6 +302,17 @@ out_set_mode:
  * by the fiq handler to see whether to start the transmitter. */
 #define USE_SSC_TX_TF_WORKAROUND
 volatile u_int32_t ssc_tx_pending = 0;
+
+/* This is the time that the TF FIQ should spin until before SWTRG'ing the tc_cdiv.
+ * See fdt_timing.dia. Note: This means transmission is broken without USE_SSC_TX_TF_WORKAROUND */
+volatile u_int32_t ssc_tx_fiq_fdt_cdiv = 0;
+/* This is the time that the TF FIQ should spin until before starting the SSC 
+ * There must be enough time between these two! */
+volatile u_int32_t ssc_tx_fiq_fdt_ssc = 0;
+#ifndef USE_SSC_TX_TF_WORKAROUND
+#error Transmission is broken without USE_SSC_TX_TF_WORKAROUND, see comments in code
+#endif
+
 void ssc_tf_irq(u_int32_t pio);
 void ssc_tx_start(ssc_dma_tx_buffer_t *buf)
 {
@@ -613,8 +624,8 @@ void ssc_rx_init(void)
 	AT91F_SSC_EnableIt(ssc, AT91C_SSC_OVRUN |
 			   AT91C_SSC_ENDRX | AT91C_SSC_RXBUFF);
 #endif
-	/* FIXME: This is hardcoded for REQA 0x26 */
-	tc_fdt_set(ISO14443A_FDT_SHORT_0);
+	/* Will be set to a real value some time later */
+	tc_fdt_set(0xff00);
 
 	AT91F_AIC_EnableIt(AT91C_ID_SSC);
 
diff --git a/openpicc/application/ssc_picc.h b/openpicc/application/ssc_picc.h
index df6da36..5eb1160 100644
--- a/openpicc/application/ssc_picc.h
+++ b/openpicc/application/ssc_picc.h
@@ -84,5 +84,7 @@ typedef struct {
 extern ssc_dma_tx_buffer_t ssc_tx_buffer;
 
 extern void ssc_tx_start(ssc_dma_tx_buffer_t *buf);
+extern volatile u_int32_t ssc_tx_fiq_fdt_cdiv;
+extern volatile u_int32_t ssc_tx_fiq_fdt_ssc;
 
 #endif
diff --git a/openpicc/application/tc_fdt.c b/openpicc/application/tc_fdt.c
index 6005125..7413e11 100644
--- a/openpicc/application/tc_fdt.c
+++ b/openpicc/application/tc_fdt.c
@@ -53,8 +53,8 @@ void tc_fdt_set(u_int16_t count)
 void __ramfunc tc_fdt_set_to_next_slot(int last_bit)
 {
 	int reference_time;
-	if(last_bit == 0) reference_time = ISO14443A_FDT_OFFSET_0-FALLING_EDGE_DETECTION_DELAY;
-	else reference_time = ISO14443A_FDT_OFFSET_1-FALLING_EDGE_DETECTION_DELAY;
+	if(last_bit == 0) reference_time = ISO14443A_FDT_OFFSET_0;
+	else reference_time = ISO14443A_FDT_OFFSET_1;
 	
 	if(tcfdt->TC_SR & AT91C_TC_CLKSTA) 
 		while(tcfdt->TC_CV != 0xFFFF && (tcfdt->TC_CV - reference_time) % 128 != 0);