diff options
Diffstat (limited to 'protocol/ps2_usart.c')
| -rw-r--r-- | protocol/ps2_usart.c | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/protocol/ps2_usart.c b/protocol/ps2_usart.c index d491142868..27947143ee 100644 --- a/protocol/ps2_usart.c +++ b/protocol/ps2_usart.c @@ -82,13 +82,14 @@ uint8_t ps2_host_send(uint8_t data) /* terminate a transmission if we have */ inhibit(); - _delay_us(100); + _delay_us(100); // [4]p.13 - /* start bit [1] */ + /* 'Request to Send' and Start bit */ data_lo(); clock_hi(); - WAIT(clock_lo, 15000, 1); - /* data [2-9] */ + WAIT(clock_lo, 10000, 10); // 10ms [5]p.50 + + /* Data bit[2-9] */ for (uint8_t i = 0; i < 8; i++) { _delay_us(15); if (data&(1<<i)) { @@ -100,15 +101,18 @@ uint8_t ps2_host_send(uint8_t data) WAIT(clock_hi, 50, 2); WAIT(clock_lo, 50, 3); } - /* parity [10] */ + + /* Parity bit */ _delay_us(15); if (parity) { data_hi(); } else { data_lo(); } WAIT(clock_hi, 50, 4); WAIT(clock_lo, 50, 5); - /* stop bit [11] */ + + /* Stop bit */ _delay_us(15); data_hi(); - /* ack [12] */ + + /* Ack */ WAIT(data_lo, 50, 6); WAIT(clock_lo, 50, 7); @@ -127,12 +131,12 @@ ERROR: return 0; } -// Do polling data from keyboard to get response to last command. uint8_t ps2_host_recv_response(void) { + // Command may take 25ms/20ms at most([5]p.46, [3]p.21) uint8_t retry = 25; while (retry-- && !pbuf_has_data()) { - _delay_ms(1); // without this delay it seems to fall into deadlock + _delay_ms(1); } return pbuf_dequeue(); } @@ -188,7 +192,6 @@ static inline void pbuf_enqueue(uint8_t data) } SREG = sreg; } - static inline uint8_t pbuf_dequeue(void) { uint8_t val = 0; |