1 files changed, 172 insertions, 0 deletions
diff --git a/openpicc/application/iso14443_layer2a.c b/openpicc/application/iso14443_layer2a.c
new file mode 100644
index 0000000..b91b67c
--- /dev/null
+++ b/openpicc/application/iso14443_layer2a.c
@@ -0,0 +1,172 @@
+/***************************************************************
+ *
+ * OpenPICC - ISO 14443 Layer 2 Type A PICC transceiver code
+ * Manages receiving, sending and parts of framing
+ * 
+ * This does not fully implement layer 2 in that it won't 
+ * automatically call the Miller decoder or Manchester encoder
+ * for you. Instead you'll be given ssc rx buffer pointers and
+ * are expected to hand in ssc tx buffer pointers. You've got
+ * to call iso14443a_manchester and iso14443a_miller yourself.
+ * The reason is that this makes it possible for the layer 3
+ * implementation to work on raw samples without en/de-coding
+ * time to enable fast responses during anticollision.
+ *
+ * Copyright 2008 Henryk Plötz <henryk@ploetzli.ch>
+ *
+ ***************************************************************
+
+    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; version 2.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+*/
+
+#include <FreeRTOS.h>
+#include <board.h>
+#include <task.h>
+#include <errno.h>
+
+#include "openpicc.h"
+#include "iso14443_layer2a.h"
+#include "ssc_picc.h"
+#include "pll.h"
+#include "tc_fdt.h"
+#include "tc_cdiv.h"
+#include "tc_cdiv_sync.h"
+#include "load_modulation.h"
+
+static u_int8_t fast_receive;
+static volatile u_int8_t receiving = 0;
+
+#ifdef FOUR_TIMES_OVERSAMPLING
+#define RX_DIVIDER 32
+#else
+#define RX_DIVIDER 64
+#endif
+
+int iso14443_receive(iso14443_receive_callback_t callback, ssc_dma_rx_buffer_t **buffer, unsigned int timeout)
+{
+	int was_receiving = receiving;
+	(void)callback;
+	ssc_dma_rx_buffer_t* _buffer = NULL;
+	int len;
+	
+	
+	if(!was_receiving) {
+		iso14443_l2a_rx_start();
+	} else {
+		/*
+		 * handled by _iso14443_ssc_irq_ext below
+		tc_fdt_set(0xff00);
+		tc_cdiv_set_divider(RX_DIVIDER);
+		tc_cdiv_sync_reset();
+		*/
+	}
+	
+	
+	if(xQueueReceive(ssc_rx_queue, &_buffer, timeout)) {
+		if(!was_receiving) {
+			iso14443_l2a_rx_stop();
+		}
+		
+		if(_buffer == NULL) {
+			/* Can this happen? */
+			return -ETIMEDOUT;
+		}
+		
+		portENTER_CRITICAL();
+		_buffer->state = PROCESSING;
+		portEXIT_CRITICAL();
+		
+		len = _buffer->len_transfers;
+		
+		if(buffer != NULL) *buffer = _buffer;
+		else {
+			portENTER_CRITICAL();
+			_buffer->state = FREE;
+			portEXIT_CRITICAL();
+		}
+		
+		return len;
+	}
+	
+	if(!was_receiving)
+		iso14443_l2a_rx_stop();
+	
+	return -ETIMEDOUT;
+}
+
+int iso14443_wait_for_carrier(unsigned int timeout)
+{
+	(void)timeout;
+	return 0;
+}
+
+int iso14443_l2a_rx_start(void)
+{
+	receiving = 1;
+	tc_fdt_set(0xff00);
+	tc_cdiv_set_divider(RX_DIVIDER);
+	ssc_rx_start();
+	return 0;
+}
+
+int iso14443_l2a_rx_stop(void)
+{
+	ssc_rx_stop();
+	receiving = 0;
+	return 0;
+}
+
+
+u_int8_t iso14443_set_fast_receive(u_int8_t enable_fast_receive)
+{
+	u_int8_t old_value = fast_receive;
+	fast_receive = enable_fast_receive;
+	return old_value;
+}
+
+u_int8_t iso14443_get_fast_receive(void)
+{
+	return fast_receive;
+}
+
+void _iso14443_ssc_irq_ext(u_int32_t ssc_sr, enum ssc_mode ssc_mode, u_int8_t* samples)
+{
+	(void) ssc_mode; (void) samples;
+	if( (ssc_sr & AT91C_SSC_CP1) && receiving) {
+		tc_fdt_set(0xff00);
+		tc_cdiv_set_divider(RX_DIVIDER);
+		tc_cdiv_sync_reset();
+	}
+}
+
+int iso14443_layer2a_init(u_int8_t enable_fast_receive)
+{
+	pll_init();
+    
+	tc_cdiv_init();
+	tc_fdt_init();
+	//ssc_set_irq_extension((ssc_irq_ext_t)iso14443_layer3a_irq_ext);
+	ssc_rx_init();
+	ssc_tx_init();
+	
+	load_mod_init();
+	load_mod_level(3);
+	
+	ssc_rx_mode_set(SSC_MODE_14443A);
+	ssc_set_irq_extension(_iso14443_ssc_irq_ext);
+	
+	iso14443_set_fast_receive(enable_fast_receive);
+	return 0;
+}