2 Copyright 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.
40 #include <avr/interrupt.h>
41 #include <util/delay.h>
46 static uint8_t recv_data(void);
47 static inline void clock_lo(void);
48 static inline void clock_hi(void);
49 static inline bool clock_in(void);
50 static inline void data_lo(void);
51 static inline void data_hi(void);
52 static inline bool data_in(void);
53 static inline uint16_t wait_clock_lo(uint16_t us);
54 static inline uint16_t wait_clock_hi(uint16_t us);
55 static inline uint16_t wait_data_lo(uint16_t us);
56 static inline uint16_t wait_data_hi(uint16_t us);
57 static inline void idle(void);
58 static inline void inhibit(void);
62 Primitive PS/2 Library for AVR
63 ==============================
64 Host side is only supported now.
69 High state is asserted by input with pull up.
74 http://www.computer-engineering.org/ps2protocol/
75 http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
79 #define WAIT(stat, us, err) do { \
80 if (!wait_##stat(us)) { \
87 uint8_t ps2_error = PS2_ERR_NONE;
90 void ps2_host_init(void)
101 // TODO: send using interrupt if available
102 uint8_t ps2_host_send(uint8_t data)
106 ps2_error = PS2_ERR_NONE;
110 /* terminate a transmission if we have */
117 WAIT(clock_lo, 15000, 1);
119 for (uint8_t i = 0; i < 8; i++) {
127 WAIT(clock_hi, 50, 2);
128 WAIT(clock_lo, 50, 3);
132 if (parity) { data_hi(); } else { data_lo(); }
133 WAIT(clock_hi, 50, 4);
134 WAIT(clock_lo, 50, 5);
139 WAIT(data_lo, 50, 6);
140 WAIT(clock_lo, 50, 7);
142 /* wait for idle state */
143 WAIT(clock_hi, 50, 8);
144 WAIT(data_hi, 50, 9);
146 res = ps2_host_recv_response();
157 /* receive data when host want else inhibit communication */
158 uint8_t ps2_host_recv_response(void)
162 /* terminate a transmission if we have */
166 /* release lines(idle state) */
178 uint8_t ps2_host_recv(void)
180 return ps2_host_recv_response();
183 /* ring buffer to store ps/2 key data */
185 static uint8_t pbuf[PBUF_SIZE];
186 static uint8_t pbuf_head = 0;
187 static uint8_t pbuf_tail = 0;
188 static inline void pbuf_enqueue(uint8_t data)
195 uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
196 if (next != pbuf_tail) {
197 pbuf[pbuf_head] = data;
200 debug("pbuf: full\n");
204 static inline uint8_t pbuf_dequeue(void)
210 if (pbuf_head != pbuf_tail) {
211 val = pbuf[pbuf_tail];
212 pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;
219 /* get data received by interrupt */
220 uint8_t ps2_host_recv(void)
225 ps2_host_send(0xFE); // request to resend
226 ps2_error = PS2_ERR_NONE;
229 return pbuf_dequeue();
233 #define DEBUGP_INIT() do { DDRC = 0xFF; } while (0)
234 #define DEBUGP(x) do { PORTC = x; } while (0)
236 #define DEBUGP_INIT()
244 BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7,
248 static uint8_t data = 0;
249 static uint8_t parity = 1;
251 // TODO: abort if elapse 100us from previous interrupt
253 // return unless falling edge
281 if (!(parity & 0x01))
312 static void ps2_reset(void)
317 /* send LED state to keyboard */
318 void ps2_host_set_led(uint8_t led)
325 /* called after start bit comes */
326 static uint8_t recv_data(void)
330 ps2_error = PS2_ERR_NONE;
333 WAIT(clock_lo, 1, 1);
335 WAIT(clock_hi, 50, 3);
338 for (uint8_t i = 0; i < 8; i++) {
339 WAIT(clock_lo, 50, 4);
344 WAIT(clock_hi, 50, 5);
348 WAIT(clock_lo, 50, 6);
349 if (data_in() != parity) {
350 ps2_error = PS2_ERR_PARITY;
353 WAIT(clock_hi, 50, 7);
356 WAIT(clock_lo, 50, 8);
358 WAIT(clock_hi, 50, 10);
365 static inline void clock_lo()
367 PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT);
368 PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT);
370 static inline void clock_hi()
372 /* input with pull up */
373 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
374 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
376 static inline bool clock_in()
378 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
379 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
381 return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT);
383 static inline void data_lo()
385 PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT);
386 PS2_DATA_DDR |= (1<<PS2_DATA_BIT);
388 static inline void data_hi()
390 /* input with pull up */
391 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
392 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
394 static inline bool data_in()
396 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
397 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
399 return PS2_DATA_PIN&(1<<PS2_DATA_BIT);
402 static inline uint16_t wait_clock_lo(uint16_t us)
404 while (clock_in() && us) { asm(""); _delay_us(1); us--; }
407 static inline uint16_t wait_clock_hi(uint16_t us)
409 while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
412 static inline uint16_t wait_data_lo(uint16_t us)
414 while (data_in() && us) { asm(""); _delay_us(1); us--; }
417 static inline uint16_t wait_data_hi(uint16_t us)
419 while (!data_in() && us) { asm(""); _delay_us(1); us--; }
423 /* idle state that device can send */
424 static inline void idle(void)
430 /* inhibit device to send */
431 static inline void inhibit(void)