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@ -21,9 +21,10 @@ uint8_t ibm4704_error = 0;
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void ibm4704_init(void)
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void ibm4704_init(void)
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{
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{
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inhibit(); // keep keyboard from sending
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IBM4704_INT_INIT();
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IBM4704_INT_INIT();
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IBM4704_INT_ON();
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IBM4704_INT_ON();
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idle();
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idle(); // allow keyboard sending
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}
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}
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/*
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/*
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@ -104,51 +105,44 @@ uint8_t ibm4704_recv_response(void)
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return rbuf_dequeue();
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return rbuf_dequeue();
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}
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}
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uint8_t ibm4704_recv(void)
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{
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if (rbuf_has_data()) {
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return rbuf_dequeue();
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} else {
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return -1;
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}
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}
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/*
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/*
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Keyboard to Host
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Keyboard to Host
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----------------
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----------------
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Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part.
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Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part.
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____ __ __ __ __ __ __ __ __ __ ________
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____ __ __ __ __ __ __ __ __ __ _______
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Clock \____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/
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Clock \_____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/
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____ ____ ____ ____ ____ ____ ____ ____ ____ ____
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____ ____ ____ ____ ____ ____ ____ ____ ____ ____
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Data ____/ X____X____X____X____X____X____X____X____X____X________
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Data ____/ X____X____X____X____X____X____X____X____X____X________
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Start 0 1 2 3 4 5 6 7 P Stop
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Start 0 1 2 3 4 5 6 7 P Stop
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Start bit: can be long as 300-350us.
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Start bit: can be long as 300-350us.
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Inhibit: Pull Data line down to inhibit keyboard to send.
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Inhibit: Pull Data line down to inhibit keyboard to send.
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Timing: Host reads bit while Clock is hi.
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Timing: Host reads bit while Clock is hi.(rising edge)
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Stop bit: Keyboard pulls down Data line to lo after 9th clock.
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Stop bit: Keyboard pulls down Data line to lo after 9th clock.
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*/
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*/
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uint8_t ibm4704_recv(void)
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{
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if (rbuf_has_data()) {
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return rbuf_dequeue();
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} else {
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return -1;
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}
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}
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ISR(IBM4704_INT_VECT)
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ISR(IBM4704_INT_VECT)
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{
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{
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static enum {
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static enum {
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INIT, START, BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY,
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BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY, STOP
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} state = INIT;
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} state = BIT0;
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// LSB first
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// LSB first
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static uint8_t data = 0;
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static uint8_t data = 0;
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// Odd parity
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// Odd parity
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static uint8_t parity = false;
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static uint8_t parity = false;
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ibm4704_error = 0;
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ibm4704_error = 0;
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// return unless falling edge
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if (clock_in()) { goto RETURN; } // why this occurs?
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state++;
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switch (state) {
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switch (state) {
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case START:
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// Data:Low
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WAIT(data_hi, 10, state);
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break;
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case BIT0:
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case BIT0:
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case BIT1:
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case BIT1:
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case BIT2:
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case BIT2:
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@ -169,6 +163,10 @@ ISR(IBM4704_INT_VECT)
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}
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}
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if (!parity)
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if (!parity)
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goto ERROR;
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goto ERROR;
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break;
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case STOP:
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// Data:Low
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WAIT(data_lo, 100, state);
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rbuf_enqueue(data);
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rbuf_enqueue(data);
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ibm4704_error = IBM4704_ERR_NONE;
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ibm4704_error = IBM4704_ERR_NONE;
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goto DONE;
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goto DONE;
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@ -176,13 +174,14 @@ ISR(IBM4704_INT_VECT)
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default:
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default:
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goto ERROR;
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goto ERROR;
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}
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}
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state++;
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goto RETURN;
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goto RETURN;
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ERROR:
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ERROR:
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ibm4704_error = state;
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ibm4704_error = state;
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while (ibm4704_send(0xFE)) _delay_ms(1); // resend
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while (ibm4704_send(0xFE)) _delay_ms(1); // resend
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xprintf("R:%02X%02X\n", state, data);
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xprintf("R:%02X%02X\n", state, data);
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DONE:
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DONE:
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state = INIT;
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state = BIT0;
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data = 0;
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data = 0;
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parity = false;
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parity = false;
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RETURN:
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RETURN:
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