root / trunk / cardbox / cardreader.c @ 279
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#include "cardreader.h" |
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//#define SD
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#define CR_CL (_BV(PIND5))
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#define CR_CLK (_BV(PIND6))
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#define CR_DATA (_BV(PIND7))
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#ifdef TRACK2
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#define CR_MAX_IDX 4 |
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#define CR_SS ':' // Start sentinal |
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#else
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#define CR_MAX_IDX 6 |
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#define CR_SS '%' // Start sentinal |
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#endif
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#define CR_ES '?' // End sentinal |
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// This is only written in the PCINT2 intterupt or in the main loop
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// but not concurrently. read_card acts as an implicit lock
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volatile cr_flag_t cr_flag;
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volatile uint8_t cr_buf[CR_BUF_SIZE];
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volatile uint16_t cr_buf_idx;
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volatile uint8_t read_card;
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#ifdef TRACK2
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const char cr_dict[] = {'0', '1', '2', '3', '4', '5', '6', '7', |
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'8', '9', ':', ';', '<', '=', '>', '?'}; |
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#else
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const char cr_dict[] = {' ', '!', '"', '#', '$', '%', '&', '\'', |
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'(', ')', '*', '+', ',', '-', '.', '/', |
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'0', '1', '2', '3', '4', '5', '6', '7', |
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'8', '9', ':', ';', '<', '=', '>', '?', |
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'@', 'A', 'B', 'C', 'D', 'E', 'F', 'G', |
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'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', |
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'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', |
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'X', 'Y', 'Z', '[', '\\',']', '^', '_'}; |
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#endif
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void card_reader_setup(void) { |
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// Turn on pin interrupts for pins D7, D6, D5
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PCICR = _BV(PCIE2); |
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PCMSK2 = _BV(PCINT22) | _BV(PCINT21); |
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// Make pins D7, D6, D5 inputs
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DDRD &= ~_BV(DDD7) & ~_BV(DDD6) & ~_BV(DDD5); |
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cr_buf_idx = 0;
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cr_flag = CR_NONE; |
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read_card = 0;
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} |
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int8_t parse_card(uint8_t *buf, uint8_t *buflen) { |
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int16_t i = cr_buf_idx - 1;
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uint8_t j = 0;
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uint8_t start_sentinal = 0;
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uint8_t byte_idx = 0;
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uint8_t byte = 0;
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uint8_t parity; |
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// Look for the start sentinal
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while (start_sentinal == 0) { |
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byte = (((byte >> 1) & 0x1F) | (cr_buf[i] << 5)); |
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if (cr_dict[byte] == CR_SS) {
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start_sentinal = 1;
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(buf)[j++] = cr_dict[byte]; |
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// Skip parity bit
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i--; |
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} |
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// Increment bits
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i--; |
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// Ran out of buffer to search, no start sentinal found
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if (i == 0) { |
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return CR_ERR_NO_START;
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} |
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} |
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// Prepare for reading of data
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byte = 0;
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byte_idx = 0;
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parity = 0;
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while (i >= 0) { |
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// Parity bit
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if (byte_idx == CR_MAX_IDX) {
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if (!(cr_buf[i]) != (parity % 2)) { |
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return CR_ERR_BAD_PARITY;
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} |
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(buf)[j++] = cr_dict[byte]; |
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// Stop at the stop sentinal
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if (cr_dict[byte] == CR_ES) {
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*buflen = j; |
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return 0; |
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} |
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byte_idx = 0;
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byte = 0;
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parity = 0;
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// Data bits
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} else {
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byte = (((byte >> 1) & 0x1F) | (cr_buf[i] << 5)); |
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byte_idx++; |
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parity += cr_buf[i]; |
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} |
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// Goto next bit in cr_buf
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i--; |
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} |
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return CR_ERR_NO_STOP;
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} |
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ISR(PCINT2_vect) { |
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static uint8_t reading = 0; // Currently reading |
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// Only read card if we are expecting it
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if (!read_card) {
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return;
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} |
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// Check if the card is inserted or not
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if (!(PIND & CR_CL) && (!reading)) {
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cr_flag = CR_NONE; |
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cr_buf_idx = 0;
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reading = 1;
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// check if the card has finished swiping
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} else if (PIND & CR_CL) { |
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cr_flag = CR_GOOD; |
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reading = 0;
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return;
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} |
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// Read data in on the downtick of the clock
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if ((!(PIND & CR_CLK)) && (cr_buf_idx < CR_BUF_SIZE)) {
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// Read data from card reader and flip since ours inverts
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cr_buf[cr_buf_idx] = !(PIND & CR_DATA); |
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cr_buf_idx++; |
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} |
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} |