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Diffstat (limited to 'tmk_core/protocol/ibm4704.c')
| -rw-r--r-- | tmk_core/protocol/ibm4704.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/tmk_core/protocol/ibm4704.c b/tmk_core/protocol/ibm4704.c new file mode 100644 index 000000000..6a03cd441 --- /dev/null +++ b/tmk_core/protocol/ibm4704.c @@ -0,0 +1,189 @@ +/* +Copyright 2010,2011,2012,2013 Jun WAKO <wakojun@gmail.com> +*/ +#include <stdbool.h> +#include <util/delay.h> +#include "debug.h" +#include "ring_buffer.h" +#include "ibm4704.h" + + +#define WAIT(stat, us, err) do { \ + if (!wait_##stat(us)) { \ + ibm4704_error = err; \ + goto ERROR; \ + } \ +} while (0) + + +uint8_t ibm4704_error = 0; + + +void ibm4704_init(void) +{ + inhibit(); // keep keyboard from sending + IBM4704_INT_INIT(); + IBM4704_INT_ON(); + idle(); // allow keyboard sending +} + +/* +Host to Keyboard +---------------- +Data bits are LSB first and Parity is odd. Clock has around 60us high and 30us low part. + + ____ __ __ __ __ __ __ __ __ __ ________ +Clock \______/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ + ^ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ___ +Data ____|__/ X____X____X____X____X____X____X____X____X____X \___ + | Start 0 1 2 3 4 5 6 7 P Stop + Request by host + +Start bit: can be long as 300-350us. +Request: Host pulls Clock line down to request to send a command. +Timing: After Request keyboard pull up Data and down Clock line to low for start bit. + After request host release Clock line once Data line becomes hi. + Host writes a bit while Clock is hi and Keyboard reads while low. +Stop bit: Host releases or pulls up Data line to hi after 9th clock and waits for keyboard pull down the line to lo. +*/ +uint8_t ibm4704_send(uint8_t data) +{ + bool parity = true; // odd parity + ibm4704_error = 0; + + IBM4704_INT_OFF(); + + /* Request to send */ + idle(); + clock_lo(); + + /* wait for Start bit(Clock:lo/Data:hi) */ + WAIT(data_hi, 300, 0x30); + + /* Data bit */ + for (uint8_t i = 0; i < 8; i++) { + WAIT(clock_hi, 100, 0x40+i); + if (data&(1<<i)) { + parity = !parity; + data_hi(); + } else { + data_lo(); + } + WAIT(clock_lo, 100, 0x48+i); + } + + /* Parity bit */ + WAIT(clock_hi, 100, 0x34); + if (parity) { data_hi(); } else { data_lo(); } + WAIT(clock_lo, 100, 0x35); + + /* Stop bit */ + WAIT(clock_hi, 100, 0x34); + data_hi(); + + /* End */ + WAIT(data_lo, 100, 0x36); + + idle(); + IBM4704_INT_ON(); + return 0; +ERROR: + idle(); + if (ibm4704_error > 0x30) { + xprintf("S:%02X ", ibm4704_error); + } + IBM4704_INT_ON(); + return -1; +} + +/* wait forever to receive data */ +uint8_t ibm4704_recv_response(void) +{ + while (!rbuf_has_data()) { + _delay_ms(1); + } + 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 \_____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ + ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ +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.(rising edge) +Stop bit: Keyboard pulls down Data line to lo after 9th clock. +*/ +ISR(IBM4704_INT_VECT) +{ + static enum { + 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; + + switch (state) { + case BIT0: + case BIT1: + case BIT2: + case BIT3: + case BIT4: + case BIT5: + case BIT6: + case BIT7: + data >>= 1; + if (data_in()) { + data |= 0x80; + parity = !parity; + } + break; + case PARITY: + if (data_in()) { + parity = !parity; + } + if (!parity) + goto ERROR; + break; + case STOP: + // Data:Low + WAIT(data_lo, 100, state); + rbuf_enqueue(data); + ibm4704_error = IBM4704_ERR_NONE; + goto DONE; + break; + 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 = BIT0; + data = 0; + parity = false; +RETURN: + return; +} |