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Diffstat (limited to 'protocol/ps2_usart.c')
| -rw-r--r-- | protocol/ps2_usart.c | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/protocol/ps2_usart.c b/protocol/ps2_usart.c new file mode 100644 index 0000000000..7d591c6506 --- /dev/null +++ b/protocol/ps2_usart.c @@ -0,0 +1,324 @@ +/* +Copyright 2010,2011 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. +*/ + +/* +Primitive PS/2 Library for AVR +============================== +Host side is only supported now. +Synchronous USART is used to receive data by hardware process +rather than interrupt. During V-USB interrupt runs, CLOCK interrupt +cannot interpose. In the result it is prone to lost CLOCK edge. + + +I/O control +----------- +High state is asserted by internal pull-up. +If you have a signaling problem, you may need to have +external pull-up resisters on CLOCK and DATA line. + + +PS/2 References +--------------- +http://www.computer-engineering.org/ps2protocol/ +http://www.mcamafia.de/pdf/ibm_hitrc07.pdf +*/ +#include <stdbool.h> +#include <avr/io.h> +#include <avr/interrupt.h> +#include <util/delay.h> +#include "ps2.h" +#include "debug.h" + + +#if 0 +#define DEBUGP_INIT() do { DDRC = 0xFF; } while (0) +#define DEBUGP(x) do { PORTC = x; } while (0) +#else +#define DEBUGP_INIT() +#define DEBUGP(x) +#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 void clock_lo(void); +static inline void clock_hi(void); +static inline bool clock_in(void); +static inline void data_lo(void); +static inline void data_hi(void); +static inline bool data_in(void); +static inline uint16_t wait_clock_lo(uint16_t us); +static inline uint16_t wait_clock_hi(uint16_t us); +static inline uint16_t wait_data_lo(uint16_t us); +static inline uint16_t wait_data_hi(uint16_t us); +static inline void idle(void); +static inline void inhibit(void); +static inline uint8_t pbuf_dequeue(void); +static inline void pbuf_enqueue(uint8_t data); + + +void ps2_host_init(void) +{ + DEBUGP_INIT(); + DEBUGP(0x1); + idle(); + PS2_USART_INIT(); + PS2_USART_RX_INT_ON(); +} + +uint8_t ps2_host_send(uint8_t data) +{ + uint8_t res = 0; + bool parity = true; + ps2_error = PS2_ERR_NONE; + + DEBUGP(0x6); + PS2_USART_OFF(); + + /* terminate a transmission if we have */ + inhibit(); + _delay_us(100); + + /* start bit [1] */ + data_lo(); + clock_hi(); + WAIT(clock_lo, 15000, 1); + /* data [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 [10] */ + _delay_us(15); + if (parity) { data_hi(); } else { data_lo(); } + WAIT(clock_hi, 50, 4); + WAIT(clock_lo, 50, 5); + /* stop bit [11] */ + _delay_us(15); + data_hi(); + /* ack [12] */ + WAIT(data_lo, 50, 6); + WAIT(clock_lo, 50, 7); + + /* wait for idle state */ + WAIT(clock_hi, 50, 8); + WAIT(data_hi, 50, 9); + + res = ps2_host_recv_response(); +ERROR: + idle(); + PS2_USART_INIT(); + PS2_USART_RX_INT_ON(); + return res; +} + +// Do polling data from keyboard to get response to last command. +uint8_t ps2_host_recv_response(void) +{ + uint8_t data = 0; + PS2_USART_INIT(); + PS2_USART_RX_POLL_ON(); + while (!PS2_USART_RX_READY) + ; + data = PS2_USART_RX_DATA; + PS2_USART_OFF(); + DEBUGP(0x9); + return data; +} + +uint8_t ps2_host_recv(void) +{ + return pbuf_dequeue(); +} + +ISR(PS2_USART_RX_VECT) +{ + DEBUGP(0x7); + uint8_t error = PS2_USART_ERROR; + uint8_t data = PS2_USART_RX_DATA; + if (error) { + DEBUGP(error>>2); + } else { + pbuf_enqueue(data); + } + DEBUGP(0x8); +} + +/* send LED state to keyboard */ +void ps2_host_set_led(uint8_t led) +{ + // send 0xED then keyboard keeps waiting for next LED data + // and keyboard does not send any scan codes during waiting. + // If fail to send LED data keyboard looks like being freezed. + uint8_t retry = 3; + while (retry-- && ps2_host_send(PS2_SET_LED) != PS2_ACK) + ; + retry = 3; + while (retry-- && ps2_host_send(led) != PS2_ACK) + ; +} + + +/*-------------------------------------------------------------------- + * static functions + *------------------------------------------------------------------*/ +static inline void clock_lo() +{ + PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT); + PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT); +} +static inline void clock_hi() +{ + /* input with pull up */ + PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT); + PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT); +} +static inline bool clock_in() +{ + PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT); + PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT); + _delay_us(1); + return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT); +} +static inline void data_lo() +{ + PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT); + PS2_DATA_DDR |= (1<<PS2_DATA_BIT); +} +static inline void data_hi() +{ + /* input with pull up */ + PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT); + PS2_DATA_PORT |= (1<<PS2_DATA_BIT); +} +static inline bool data_in() +{ + PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT); + PS2_DATA_PORT |= (1<<PS2_DATA_BIT); + _delay_us(1); + return PS2_DATA_PIN&(1<<PS2_DATA_BIT); +} + +static inline uint16_t wait_clock_lo(uint16_t us) +{ + while (clock_in() && us) { asm(""); _delay_us(1); us--; } + return us; +} +static inline uint16_t wait_clock_hi(uint16_t us) +{ + while (!clock_in() && us) { asm(""); _delay_us(1); us--; } + return us; +} +static inline uint16_t wait_data_lo(uint16_t us) +{ + while (data_in() && us) { asm(""); _delay_us(1); us--; } + return us; +} +static inline uint16_t wait_data_hi(uint16_t us) +{ + while (!data_in() && us) { asm(""); _delay_us(1); us--; } + return us; +} + +/* idle state that device can send */ +static inline void idle(void) +{ + clock_hi(); + data_hi(); +} + +/* inhibit device to send */ +static inline void inhibit(void) +{ + clock_lo(); + data_hi(); +} + + +/*-------------------------------------------------------------------- + * Ring buffer to store scan codes from keyboard + *------------------------------------------------------------------*/ +#define PBUF_SIZE 8 +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) +{ + if (!data) + return; + + 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 { + debug("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; +} |