diff options
Diffstat (limited to 'platforms/avr/drivers/ps2/ps2_usart.c')
| -rw-r--r-- | platforms/avr/drivers/ps2/ps2_usart.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/platforms/avr/drivers/ps2/ps2_usart.c b/platforms/avr/drivers/ps2/ps2_usart.c new file mode 100644 index 0000000000..151cfcd68f --- /dev/null +++ b/platforms/avr/drivers/ps2/ps2_usart.c @@ -0,0 +1,227 @@ +/* +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 USART version + */ + +#include <stdbool.h> +#include <avr/interrupt.h> +#include <util/delay.h> +#include "gpio.h" +#include "ps2.h" +#include "ps2_io.h" +#include "print.h" + +#ifndef PS2_CLOCK_DDR +# define PS2_CLOCK_DDR PORTx_ADDRESS(PS2_CLOCK_PIN) +#endif +#ifndef PS2_CLOCK_BIT +# define PS2_CLOCK_BIT (PS2_CLOCK_PIN & 0xF) +#endif +#ifndef PS2_DATA_DDR +# define PS2_DATA_DDR PORTx_ADDRESS(PS2_DATA_PIN) +#endif +#ifndef PS2_DATA_BIT +# define PS2_DATA_BIT (PS2_DATA_PIN & 0xF) +#endif + +#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(); // without this many USART errors occur when cable is disconnected + PS2_USART_INIT(); + PS2_USART_RX_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_USART_OFF(); + + /* terminate a transmission if we have */ + inhibit(); + _delay_us(100); // [4]p.13 + + /* '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_USART_INIT(); + PS2_USART_RX_INT_ON(); + return ps2_host_recv_response(); +ERROR: + idle(); + PS2_USART_INIT(); + PS2_USART_RX_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(); +} + +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_USART_RX_VECT) { + // TODO: request RESEND when error occurs? + uint8_t error = PS2_USART_ERROR; // USART error should be read before data + uint8_t data = PS2_USART_RX_DATA; + if (!error) { + pbuf_enqueue(data); + } else { + xprintf("PS2 USART error: %02X data: %02X\n", error, data); + } +} + +/* 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; +} |