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- /*
- Copyright 2010,2011,2012,2013 Jun WAKO <[email protected]>
-
- 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 "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(); // 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;
- }
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