151 lines
4.1 KiB
C
151 lines
4.1 KiB
C
/* ISO14443A Miller decoder for OpenPICC
|
|
* (C) 2007 by 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; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*
|
|
*/
|
|
|
|
#include <openpicc.h>
|
|
#include <FreeRTOS.h>
|
|
|
|
#include <string.h>
|
|
|
|
#include "iso14443_layer3a.h"
|
|
#include "usb_print.h"
|
|
#include "ssc_buffer.h"
|
|
#include "cmd.h"
|
|
|
|
#if 0
|
|
// With debugging
|
|
#define MILLER_DEBUG_STRING DumpStringToUSB
|
|
#define MILLER_DEBUG_UINT DumpUIntToUSB
|
|
#else
|
|
// Without debugging
|
|
#define MILLER_DEBUG_STRING(...) if(0){(void)__VA_ARGS__;}
|
|
#define MILLER_DEBUG_UINT(...) if(0){(void)__VA_ARGS__;}
|
|
#endif
|
|
|
|
#ifdef FOUR_TIMES_OVERSAMPLING
|
|
#define OVERSAMPLING_RATE 4
|
|
|
|
/* definitions for four-times oversampling */
|
|
#define SEQ_X 0x4
|
|
#define SEQ_Y 0x0
|
|
#define SEQ_Z 0x1
|
|
#else
|
|
#define OVERSAMPLING_RATE 2
|
|
#define SEQ_X 0x2
|
|
#define SEQ_Y 0x0
|
|
#define SEQ_Z 0x1
|
|
#endif
|
|
|
|
enum miller_sequence {
|
|
SEQUENCE_X,
|
|
SEQUENCE_Y,
|
|
SEQUENCE_Z,
|
|
};
|
|
|
|
#define BIT_ENDMARKER -1
|
|
|
|
static const int BITSAMPLE_MASK = ~(~0 << OVERSAMPLING_RATE);
|
|
|
|
int iso14443a_decode_miller(iso14443_frame *frame,
|
|
const ssc_dma_rx_buffer_t * const buffer)
|
|
{
|
|
u_int32_t i,j;
|
|
signed int bit = 0, last_bit = ISO14443A_LAST_BIT_NONE, next_to_last_bit = ISO14443A_LAST_BIT_NONE;
|
|
enum miller_sequence current_seq;
|
|
unsigned int bitpos = 0;
|
|
|
|
memset(frame, 0, sizeof(*frame));
|
|
frame->type = TYPE_A;
|
|
frame->parameters.a.parity = GIVEN_PARITY;
|
|
|
|
u_int32_t sample = 0;
|
|
u_int8_t *sample_8=0;
|
|
u_int16_t *sample_16=0;
|
|
u_int32_t *sample_32=0;
|
|
|
|
switch(buffer->reception_mode->transfersize_pdc) {
|
|
case 8: sample_8 = ((u_int8_t*)buffer->data); break;
|
|
case 16: sample_16 = ((u_int16_t*)buffer->data); break;
|
|
case 32: sample_32 = ((u_int32_t*)buffer->data); break;
|
|
}
|
|
|
|
for(i=0; i<buffer->len_transfers && bit != BIT_ENDMARKER; i++) {
|
|
MILLER_DEBUG_STRING(" ");
|
|
switch(buffer->reception_mode->transfersize_pdc) {
|
|
case 8: sample = *sample_8++; break;
|
|
case 16: sample = *sample_16++; break;
|
|
case 32: sample = *sample_32++; break;
|
|
}
|
|
MILLER_DEBUG_UINT(sample);
|
|
|
|
for(j=0; j<buffer->reception_mode->transfersize_ssc && bit != BIT_ENDMARKER; j+=OVERSAMPLING_RATE) {
|
|
MILLER_DEBUG_STRING(".");
|
|
int bitsample = (sample>>j) & BITSAMPLE_MASK;
|
|
switch(bitsample) {
|
|
case SEQ_X: current_seq = SEQUENCE_X; MILLER_DEBUG_STRING("X"); break;
|
|
case SEQ_Y: current_seq = SEQUENCE_Y; MILLER_DEBUG_STRING("Y"); break;
|
|
case SEQ_Z: current_seq = SEQUENCE_Z; MILLER_DEBUG_STRING("Z"); break;
|
|
default: MILLER_DEBUG_UINT(bitsample); current_seq = SEQUENCE_Y;
|
|
}
|
|
|
|
switch(current_seq) {
|
|
case SEQUENCE_X:
|
|
bit = 1; break;
|
|
case SEQUENCE_Y: /* Fall-through to SEQUENCE_Z */
|
|
if(last_bit == 0) {
|
|
bit = BIT_ENDMARKER;
|
|
MILLER_DEBUG_STRING("!");
|
|
break;
|
|
}
|
|
case SEQUENCE_Z:
|
|
bit = 0; break;
|
|
}
|
|
|
|
switch(bit) {
|
|
case BIT_ENDMARKER:
|
|
bitpos-=2; /* Subtract this sequence and the previous sequence (which was a 0) */
|
|
frame->parameters.a.last_bit = next_to_last_bit;
|
|
break;
|
|
case 0: /* Fall-through */
|
|
case 1: {
|
|
int bytepos = bitpos/9;
|
|
if(bitpos % 9 == 8) { /* Parity bit */
|
|
frame->parity[ bytepos/8 ] |= (bit<<(bytepos%8));
|
|
} else {
|
|
frame->data[ bytepos ] |= (bit<<(bitpos%9));
|
|
}
|
|
}
|
|
}
|
|
|
|
next_to_last_bit = last_bit;
|
|
last_bit = bit;
|
|
bitpos++;
|
|
}
|
|
}
|
|
|
|
frame->numbytes = bitpos/9;
|
|
frame->numbits = bitpos%9;
|
|
MILLER_DEBUG_STRING(" ");
|
|
MILLER_DEBUG_UINT(frame->numbytes);
|
|
MILLER_DEBUG_STRING(" bytes, ");
|
|
MILLER_DEBUG_UINT(frame->numbits);
|
|
MILLER_DEBUG_STRING(" bits ");
|
|
|
|
return 0;
|
|
}
|