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/***************************************************************
*
* 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;
}
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