2 Copyright (c) 2010,2011 Jun WAKO <wakojun@gmail.com>
4 This software is licensed with a Modified BSD License.
5 All of this is supposed to be Free Software, Open Source, DFSG-free,
6 GPL-compatible, and OK to use in both free and proprietary applications.
7 Additions and corrections to this file are welcome.
10 Redistribution and use in source and binary forms, with or without
11 modification, are permitted provided that the following conditions are met:
13 * Redistributions of source code must retain the above copyright
14 notice, this list of conditions and the following disclaimer.
16 * Redistributions in binary form must reproduce the above copyright
17 notice, this list of conditions and the following disclaimer in
18 the documentation and/or other materials provided with the
21 * Neither the name of the copyright holders nor the names of
22 contributors may be used to endorse or promote products derived
23 from this software without specific prior written permission.
25 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
26 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
29 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 POSSIBILITY OF SUCH DAMAGE.
39 #include <avr/interrupt.h>
40 #include <util/delay.h>
45 static uint8_t recv_data(void);
46 static inline void clock_lo(void);
47 static inline void clock_hi(void);
48 static inline bool clock_in(void);
49 static inline void data_lo(void);
50 static inline void data_hi(void);
51 static inline bool data_in(void);
52 static inline uint16_t wait_clock_lo(uint16_t us);
53 static inline uint16_t wait_clock_hi(uint16_t us);
54 static inline uint16_t wait_data_lo(uint16_t us);
55 static inline uint16_t wait_data_hi(uint16_t us);
56 static inline void idle(void);
57 static inline void inhibit(void);
61 Primitive PS/2 Library for AVR
62 ==============================
63 Host side is only supported now.
68 High state is asserted by input with pull up.
73 http://www.computer-engineering.org/ps2protocol/
74 http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
78 #define WAIT(stat, us, err) do { \
79 if (!wait_##stat(us)) { \
86 uint8_t ps2_error = PS2_ERR_NONE;
89 void ps2_host_init(void)
99 // TODO: send using interrupt if available
100 uint8_t ps2_host_send(uint8_t data)
104 ps2_error = PS2_ERR_NONE;
105 #ifdef PS2_INT_DISABLE
108 /* terminate a transmission if we have */
115 WAIT(clock_lo, 15000, 1);
117 for (uint8_t i = 0; i < 8; i++) {
125 WAIT(clock_hi, 50, 2);
126 WAIT(clock_lo, 50, 3);
130 if (parity) { data_hi(); } else { data_lo(); }
131 WAIT(clock_hi, 50, 4);
132 WAIT(clock_lo, 50, 5);
137 WAIT(data_lo, 50, 6);
138 WAIT(clock_lo, 50, 7);
140 /* wait for idle state */
141 WAIT(clock_hi, 50, 8);
142 WAIT(data_hi, 50, 9);
144 res = ps2_host_recv_response();
146 #ifdef PS2_INT_ENABLE
155 /* receive data when host want else inhibit communication */
156 uint8_t ps2_host_recv_response(void)
160 /* terminate a transmission if we have */
164 /* release lines(idle state) */
176 uint8_t ps2_host_recv(void)
178 return ps2_host_recv_response();
181 /* ring buffer to store ps/2 key data */
183 static uint8_t pbuf[PBUF_SIZE];
184 static uint8_t pbuf_head = 0;
185 static uint8_t pbuf_tail = 0;
186 static inline void pbuf_enqueue(uint8_t data)
193 uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
194 if (next != pbuf_tail) {
195 pbuf[pbuf_head] = data;
198 debug("pbuf: full\n");
202 static inline uint8_t pbuf_dequeue(void)
208 if (pbuf_head != pbuf_tail) {
209 val = pbuf[pbuf_tail];
210 pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;
217 /* get data received by interrupt */
218 uint8_t ps2_host_recv(void)
223 ps2_host_send(0xFE); // request to resend
224 ps2_error = PS2_ERR_NONE;
227 return pbuf_dequeue();
231 #define DEBUGP_INIT() do { DDRC = 0xFF; } while (0)
232 #define DEBUGP(x) do { PORTC = x; } while (0)
234 #define DEBUGP_INIT()
242 BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7,
246 static uint8_t data = 0;
247 static uint8_t parity = 1;
249 // TODO: abort if elapse 100us from previous interrupt
251 // return unless falling edge
279 if (!(parity & 0x01))
310 static void ps2_reset(void)
315 /* send LED state to keyboard */
316 void ps2_host_set_led(uint8_t led)
323 /* called after start bit comes */
324 static uint8_t recv_data(void)
328 ps2_error = PS2_ERR_NONE;
331 WAIT(clock_lo, 1, 1);
333 WAIT(clock_hi, 50, 3);
336 for (uint8_t i = 0; i < 8; i++) {
337 WAIT(clock_lo, 50, 4);
342 WAIT(clock_hi, 50, 5);
346 WAIT(clock_lo, 50, 6);
347 if (data_in() != parity) {
348 ps2_error = PS2_ERR_PARITY;
351 WAIT(clock_hi, 50, 7);
354 WAIT(clock_lo, 50, 8);
356 WAIT(clock_hi, 50, 10);
363 static inline void clock_lo()
365 PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT);
366 PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT);
368 static inline void clock_hi()
370 /* input with pull up */
371 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
372 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
374 static inline bool clock_in()
376 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
377 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
379 return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT);
381 static inline void data_lo()
383 PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT);
384 PS2_DATA_DDR |= (1<<PS2_DATA_BIT);
386 static inline void data_hi()
388 /* input with pull up */
389 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
390 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
392 static inline bool data_in()
394 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
395 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
397 return PS2_DATA_PIN&(1<<PS2_DATA_BIT);
400 static inline uint16_t wait_clock_lo(uint16_t us)
402 while (clock_in() && us) { asm(""); _delay_us(1); us--; }
405 static inline uint16_t wait_clock_hi(uint16_t us)
407 while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
410 static inline uint16_t wait_data_lo(uint16_t us)
412 while (data_in() && us) { asm(""); _delay_us(1); us--; }
415 static inline uint16_t wait_data_hi(uint16_t us)
417 while (!data_in() && us) { asm(""); _delay_us(1); us--; }
421 /* idle state that device can send */
422 static inline void idle(void)
428 /* inhibit device to send */
429 static inline void inhibit(void)