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#ifndef ISO14443_H_
#define ISO14443_H_
/******************** RX ************************************/
#define ISO14443_BITS_PER_SSC_TRANSFER 4
#ifdef FOUR_TIMES_OVERSAMPLING
/* definitions for four-times oversampling */
#define ISO14443A_SAMPLE_LEN 4
/* Sample values for the REQA and WUPA short frames */
#define REQA 0x10410441
#define WUPA 0x04041041
/* Start of frame sample for SSC compare 0 */
#define ISO14443A_SOF_SAMPLE 0x01
#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 */
#define ISO14443A_SAMPLE_LEN 2
/* For SSC_MODE_ISO14443A_SHORT */
#define ISO14443A_SHORT_LEN 18
#define REQA 0x4929
#define WUPA 0x2249
#define ISO14443A_SOF_SAMPLE 0x01
#define ISO14443A_SOF_LEN 2
#define ISO14443A_EOF_SAMPLE 0x00
#define ISO14443A_EOF_LEN 7
/* For SSC_MODE_ISO14443A */
#define ISO14443A_SHORT_FRAME_COMPARE_LENGTH 2
#define _ISO14443A_SHORT_FRAME_REQA { 0x29, 0x49 }
#define _ISO14443A_SHORT_FRAME_WUPA { 0x49, 0x22 }
// FIXME not correct. This should be compare_length == 3 (which is 9 samples at 4 per compare), but this
// needs enhanced ssc irq code to transfer the last read (incomplete) data from the ssc holding
// register to the buffer
#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
/******************** RX and TX *****************************/
/* in bytes, not counting parity */
#define MAXIMUM_FRAME_SIZE 256
#define ISO14443A_MAX_RX_FRAME_SIZE_IN_BITS (MAXIMUM_FRAME_SIZE*9 +2)
typedef enum {
FRAME_FREE=0, /* Frame is free */
FRAME_PENDING, /* Frame is currently filled by Rx */
FRAME_FULL, /* Frame has been filled by Rx */
FRAME_PROCESSING,/* The frame is currently processed by the consumer */
FRAME_PREFILLED, /* The frame has been prefilled for later usage (only used for TX) */
} iso14443_frame_state_t;
typedef struct {
enum { TYPE_A, TYPE_B } type;
iso14443_frame_state_t state;
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;
enum { ISO14443A_LAST_BIT_0 = 0, ISO14443A_LAST_BIT_1 = 1, ISO14443A_LAST_BIT_NONE } last_bit;
enum { CRC_UNCALCULATED = 2, CRC_OK = 1, CRC_ERROR = 0} crc;
} 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/8+1]; /* parity bit for data[x] is in parity[x/8] & (1<<(x%8)) */
} iso14443_frame;
#endif /*ISO14443_H_*/
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