diff options
Diffstat (limited to 'tmk_core/protocol/ibm4704.c')
-rw-r--r-- | tmk_core/protocol/ibm4704.c | 45 |
1 files changed, 22 insertions, 23 deletions
diff --git a/tmk_core/protocol/ibm4704.c b/tmk_core/protocol/ibm4704.c index a10a5e74d..6a03cd441 100644 --- a/tmk_core/protocol/ibm4704.c +++ b/tmk_core/protocol/ibm4704.c @@ -21,9 +21,10 @@ uint8_t ibm4704_error = 0; void ibm4704_init(void) { + inhibit(); // keep keyboard from sending IBM4704_INT_INIT(); IBM4704_INT_ON(); - idle(); + idle(); // allow keyboard sending } /* @@ -104,51 +105,44 @@ uint8_t ibm4704_recv_response(void) return rbuf_dequeue(); } +uint8_t ibm4704_recv(void) +{ + if (rbuf_has_data()) { + return rbuf_dequeue(); + } else { + return -1; + } +} + /* Keyboard to Host ---------------- Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part. - ____ __ __ __ __ __ __ __ __ __ ________ -Clock \____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ + ____ __ __ __ __ __ __ __ __ __ _______ +Clock \_____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ Data ____/ X____X____X____X____X____X____X____X____X____X________ Start 0 1 2 3 4 5 6 7 P Stop Start bit: can be long as 300-350us. Inhibit: Pull Data line down to inhibit keyboard to send. -Timing: Host reads bit while Clock is hi. +Timing: Host reads bit while Clock is hi.(rising edge) Stop bit: Keyboard pulls down Data line to lo after 9th clock. */ -uint8_t ibm4704_recv(void) -{ - if (rbuf_has_data()) { - return rbuf_dequeue(); - } else { - return -1; - } -} - ISR(IBM4704_INT_VECT) { static enum { - INIT, START, BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY, - } state = INIT; + BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, PARITY, STOP + } state = BIT0; // LSB first static uint8_t data = 0; // Odd parity static uint8_t parity = false; ibm4704_error = 0; - // return unless falling edge - if (clock_in()) { goto RETURN; } // why this occurs? - state++; switch (state) { - case START: - // Data:Low - WAIT(data_hi, 10, state); - break; case BIT0: case BIT1: case BIT2: @@ -169,6 +163,10 @@ ISR(IBM4704_INT_VECT) } if (!parity) goto ERROR; + break; + case STOP: + // Data:Low + WAIT(data_lo, 100, state); rbuf_enqueue(data); ibm4704_error = IBM4704_ERR_NONE; goto DONE; @@ -176,13 +174,14 @@ ISR(IBM4704_INT_VECT) default: goto ERROR; } + state++; goto RETURN; ERROR: ibm4704_error = state; while (ibm4704_send(0xFE)) _delay_ms(1); // resend xprintf("R:%02X%02X\n", state, data); DONE: - state = INIT; + state = BIT0; data = 0; parity = false; RETURN: |