diff options
Diffstat (limited to 'protocol/ps2_interrupt.c')
| -rw-r--r-- | protocol/ps2_interrupt.c | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/protocol/ps2_interrupt.c b/protocol/ps2_interrupt.c new file mode 100644 index 0000000000..259d254007 --- /dev/null +++ b/protocol/ps2_interrupt.c @@ -0,0 +1,278 @@ +/* +Copyright 2010,2011,2012,2013 Jun WAKO <wakojun@gmail.com> + +This software is licensed with a Modified BSD License. +All of this is supposed to be Free Software, Open Source, DFSG-free, +GPL-compatible, and OK to use in both free and proprietary applications. +Additions and corrections to this file are welcome. + + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + +* Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + +* Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in + the documentation and/or other materials provided with the + distribution. + +* Neither the name of the copyright holders nor the names of + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +POSSIBILITY OF SUCH DAMAGE. +*/ + +/* + * PS/2 protocol Pin interrupt version + */ + +#include <stdbool.h> +#include <avr/interrupt.h> +#include <util/delay.h> +#include "ps2.h" +#include "print.h" + + +#define WAIT(stat, us, err) do { \ + if (!wait_##stat(us)) { \ + ps2_error = err; \ + goto ERROR; \ + } \ +} while (0) + + +uint8_t ps2_error = PS2_ERR_NONE; + + +static inline uint8_t pbuf_dequeue(void); +static inline void pbuf_enqueue(uint8_t data); +static inline bool pbuf_has_data(void); +static inline void pbuf_clear(void); + + +void ps2_host_init(void) +{ + idle(); + PS2_INT_INIT(); + PS2_INT_ON(); + // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20) + //_delay_ms(2500); +} + +uint8_t ps2_host_send(uint8_t data) +{ + bool parity = true; + ps2_error = PS2_ERR_NONE; + + PS2_INT_OFF(); + + /* terminate a transmission if we have */ + inhibit(); + _delay_us(100); // 100us [4]p.13, [5]p.50 + + /* 'Request to Send' and Start bit */ + data_lo(); + clock_hi(); + 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)) { + parity = !parity; + data_hi(); + } else { + data_lo(); + } + WAIT(clock_hi, 50, 2); + WAIT(clock_lo, 50, 3); + } + + /* Parity bit */ + _delay_us(15); + if (parity) { data_hi(); } else { data_lo(); } + WAIT(clock_hi, 50, 4); + WAIT(clock_lo, 50, 5); + + /* Stop bit */ + _delay_us(15); + data_hi(); + + /* Ack */ + WAIT(data_lo, 50, 6); + WAIT(clock_lo, 50, 7); + + /* wait for idle state */ + WAIT(clock_hi, 50, 8); + WAIT(data_hi, 50, 9); + + idle(); + PS2_INT_ON(); + return ps2_host_recv_response(); +ERROR: + idle(); + PS2_INT_ON(); + return 0; +} + +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); + } + return pbuf_dequeue(); +} + +/* get data received by interrupt */ +uint8_t ps2_host_recv(void) +{ + if (pbuf_has_data()) { + ps2_error = PS2_ERR_NONE; + return pbuf_dequeue(); + } else { + ps2_error = PS2_ERR_NODATA; + return 0; + } +} + +ISR(PS2_INT_VECT) +{ + static enum { + INIT, + START, + BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7, + PARITY, + STOP, + } state = INIT; + static uint8_t data = 0; + static uint8_t parity = 1; + + // TODO: abort if elapse 100us from previous interrupt + + // return unless falling edge + if (clock_in()) { + goto RETURN; + } + + state++; + switch (state) { + case START: + if (data_in()) + goto ERROR; + break; + case BIT0: + case BIT1: + case BIT2: + case BIT3: + case BIT4: + case BIT5: + case BIT6: + case BIT7: + data >>= 1; + if (data_in()) { + data |= 0x80; + parity++; + } + break; + case PARITY: + if (data_in()) { + if (!(parity & 0x01)) + goto ERROR; + } else { + if (parity & 0x01) + goto ERROR; + } + break; + case STOP: + if (!data_in()) + goto ERROR; + pbuf_enqueue(data); + goto DONE; + break; + default: + goto ERROR; + } + goto RETURN; +ERROR: + ps2_error = state; +DONE: + state = INIT; + data = 0; + parity = 1; +RETURN: + return; +} + +/* send LED state to keyboard */ +void ps2_host_set_led(uint8_t led) +{ + ps2_host_send(0xED); + ps2_host_send(led); +} + + +/*-------------------------------------------------------------------- + * Ring buffer to store scan codes from keyboard + *------------------------------------------------------------------*/ +#define PBUF_SIZE 32 +static uint8_t pbuf[PBUF_SIZE]; +static uint8_t pbuf_head = 0; +static uint8_t pbuf_tail = 0; +static inline void pbuf_enqueue(uint8_t data) +{ + uint8_t sreg = SREG; + cli(); + uint8_t next = (pbuf_head + 1) % PBUF_SIZE; + if (next != pbuf_tail) { + pbuf[pbuf_head] = data; + pbuf_head = next; + } else { + print("pbuf: full\n"); + } + SREG = sreg; +} +static inline uint8_t pbuf_dequeue(void) +{ + uint8_t val = 0; + + uint8_t sreg = SREG; + cli(); + if (pbuf_head != pbuf_tail) { + val = pbuf[pbuf_tail]; + pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE; + } + SREG = sreg; + + return val; +} +static inline bool pbuf_has_data(void) +{ + uint8_t sreg = SREG; + cli(); + bool has_data = (pbuf_head != pbuf_tail); + SREG = sreg; + return has_data; +} +static inline void pbuf_clear(void) +{ + uint8_t sreg = SREG; + cli(); + pbuf_head = pbuf_tail = 0; + SREG = sreg; +} + |