108 lines
3.7 KiB
C
108 lines
3.7 KiB
C
#ifndef ISO14443_H_
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#define ISO14443_H_
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/******************** RX ************************************/
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#define ISO14443_BITS_PER_SSC_TRANSFER 4
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#ifdef FOUR_TIMES_OVERSAMPLING
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/* definitions for four-times oversampling */
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#define ISO14443A_SAMPLE_LEN 4
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/* Sample values for the REQA and WUPA short frames */
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#define REQA 0x10410441
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#define WUPA 0x04041041
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/* Start of frame sample for SSC compare 0 */
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#define ISO14443A_SOF_SAMPLE 0x01
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#define ISO14443A_SOF_LEN 4
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/* Length in samples of a short frame */
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#define ISO14443A_SHORT_LEN 32
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/* This is wrong: a short frame is 1 start bit, 7 data bits, 1 stop bit
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* followed by no modulation for one bit period. The start bit is 'eaten' in
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* SSC Compare 0, but the remaining 7+1+1 bit durations must be sampled and
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* compared. At four times oversampling this would be 9*4=36 samples, which is
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* more than one SSC transfer. You'd have to use two transfers of 18 samples
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* each and modify the comparison code accordingly.
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* Since four times oversampling doesn't work reliably anyway (every second
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* sample is near an edge and might sample 0 or 1) this doesn't matter for now.*/
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#error Four times oversampling is broken, see comments in code
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#else
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/* definitions for two-times oversampling */
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#define ISO14443A_SAMPLE_LEN 2
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/* For SSC_MODE_ISO14443A_SHORT */
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#define ISO14443A_SHORT_LEN 18
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#define REQA 0x4929
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#define WUPA 0x2249
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#define ISO14443A_SOF_SAMPLE 0x01
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#define ISO14443A_SOF_LEN 2
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#define ISO14443A_EOF_SAMPLE 0x00
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#define ISO14443A_EOF_LEN 7
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/* For SSC_MODE_ISO14443A */
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#define ISO14443A_SHORT_FRAME_COMPARE_LENGTH 2
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#define _ISO14443A_SHORT_FRAME_REQA { 0x29, 0x49 }
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#define _ISO14443A_SHORT_FRAME_WUPA { 0x49, 0x22 }
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// FIXME not correct. This should be compare_length == 3 (which is 9 samples at 4 per compare), but this
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// needs enhanced ssc irq code to transfer the last read (incomplete) data from the ssc holding
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// register to the buffer
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#endif
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/* A short frame should be received in one single SSC transfer */
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#if (ISO14443A_SHORT_LEN <= 8)
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/* SSC transfer size in bits */
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#define ISO14443A_SHORT_TRANSFER_SIZE 8
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#define ISO14443A_SHORT_TYPE u_int8_t
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#elif (ISO14443A_SHORT_LEN <= 16)
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#define ISO14443A_SHORT_TRANSFER_SIZE 16
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#define ISO14443A_SHORT_TYPE u_int16_t
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#elif (ISO14443A_SHORT_LEN <= 32)
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#define ISO14443A_SHORT_TRANSFER_SIZE 32
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#define ISO14443A_SHORT_TYPE u_int32_t
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#else
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#error ISO14443A_SHORT_LEN defined too big
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#endif
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/******************** RX and TX *****************************/
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/* in bytes, not counting parity */
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#define MAXIMUM_FRAME_SIZE 256
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#define ISO14443A_MAX_RX_FRAME_SIZE_IN_BITS (MAXIMUM_FRAME_SIZE*9 +2)
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typedef enum {
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FRAME_FREE=0, /* Frame is free */
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FRAME_PENDING, /* Frame is currently filled by Rx */
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FRAME_FULL, /* Frame has been filled by Rx */
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FRAME_PROCESSING,/* The frame is currently processed by the consumer */
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FRAME_PREFILLED, /* The frame has been prefilled for later usage (only used for TX) */
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} iso14443_frame_state_t;
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typedef struct {
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enum { TYPE_A, TYPE_B } type;
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iso14443_frame_state_t state;
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union {
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struct {
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enum { SHORT_FRAME, STANDARD_FRAME, AC_FRAME } format;
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enum { PARITY, /* Calculate parity on the fly, ignore the parity field below */
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GIVEN_PARITY, /* Use the parity bits from the parity field below */
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NO_PARITY, /* Don't send any parity */
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} parity;
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enum { ISO14443A_LAST_BIT_0 = 0, ISO14443A_LAST_BIT_1 = 1, ISO14443A_LAST_BIT_NONE } last_bit;
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enum { CRC_UNCALCULATED = 2, CRC_OK = 1, CRC_ERROR = 0} crc;
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} a;
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} parameters;
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u_int32_t numbytes;
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u_int8_t numbits, bit_offset;
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u_int8_t data[MAXIMUM_FRAME_SIZE];
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u_int8_t parity[MAXIMUM_FRAME_SIZE/8+1]; /* parity bit for data[x] is in parity[x/8] & (1<<(x%8)) */
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} iso14443_frame;
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#endif /*ISO14443_H_*/
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