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.
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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
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35 POSSIBILITY OF SUCH DAMAGE.
39 Primitive PS/2 Library for AVR
40 ==============================
41 Host side is only supported now.
42 Synchronous USART is used to receive data by hardware process
43 rather than interrupt. During V-USB interrupt runs, CLOCK interrupt
44 cannot interpose. In the result it is prone to lost CLOCK edge.
49 High state is asserted by internal pull-up.
50 If you have a signaling problem, you may need to have
51 external pull-up resisters on CLOCK and DATA line.
56 http://www.computer-engineering.org/ps2protocol/
57 http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
61 #include <avr/interrupt.h>
62 #include <util/delay.h>
68 #define DEBUGP_INIT() do { DDRC = 0xFF; } while (0)
69 #define DEBUGP(x) do { PORTC = x; } while (0)
75 #define WAIT(stat, us, err) do { \
76 if (!wait_##stat(us)) { \
83 uint8_t ps2_error = PS2_ERR_NONE;
86 static inline void clock_lo(void);
87 static inline void clock_hi(void);
88 static inline bool clock_in(void);
89 static inline void data_lo(void);
90 static inline void data_hi(void);
91 static inline bool data_in(void);
92 static inline uint16_t wait_clock_lo(uint16_t us);
93 static inline uint16_t wait_clock_hi(uint16_t us);
94 static inline uint16_t wait_data_lo(uint16_t us);
95 static inline uint16_t wait_data_hi(uint16_t us);
96 static inline void idle(void);
97 static inline void inhibit(void);
98 #if defined PS2_USE_INT || defined PS2_USE_USART
99 static inline uint8_t pbuf_dequeue(void);
100 static inline void pbuf_enqueue(uint8_t data);
104 void ps2_host_init(void)
110 PS2_USART_RX_INT_ON();
113 uint8_t ps2_host_send(uint8_t data)
117 ps2_error = PS2_ERR_NONE;
122 /* terminate a transmission if we have */
129 WAIT(clock_lo, 15000, 1);
131 for (uint8_t i = 0; i < 8; i++) {
139 WAIT(clock_hi, 50, 2);
140 WAIT(clock_lo, 50, 3);
144 if (parity) { data_hi(); } else { data_lo(); }
145 WAIT(clock_hi, 50, 4);
146 WAIT(clock_lo, 50, 5);
151 WAIT(data_lo, 50, 6);
152 WAIT(clock_lo, 50, 7);
154 /* wait for idle state */
155 WAIT(clock_hi, 50, 8);
156 WAIT(data_hi, 50, 9);
158 res = ps2_host_recv_response();
162 PS2_USART_RX_INT_ON();
166 // Do polling data from keyboard to get response to last command.
167 uint8_t ps2_host_recv_response(void)
171 PS2_USART_RX_POLL_ON();
172 while (!PS2_USART_RX_READY)
174 data = PS2_USART_RX_DATA;
180 uint8_t ps2_host_recv(void)
182 return pbuf_dequeue();
185 ISR(PS2_USART_RX_VECT)
188 uint8_t error = PS2_USART_ERROR;
189 uint8_t data = PS2_USART_RX_DATA;
198 /* send LED state to keyboard */
199 void ps2_host_set_led(uint8_t led)
201 // send 0xED then keyboard keeps waiting for next LED data
202 // and keyboard does not send any scan codes during waiting.
203 // If fail to send LED data keyboard looks like being freezed.
205 while (retry-- && ps2_host_send(PS2_SET_LED) != PS2_ACK)
208 while (retry-- && ps2_host_send(led) != PS2_ACK)
213 /*--------------------------------------------------------------------
215 *------------------------------------------------------------------*/
216 static inline void clock_lo()
218 PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT);
219 PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT);
221 static inline void clock_hi()
223 /* input with pull up */
224 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
225 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
227 static inline bool clock_in()
229 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
230 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
232 return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT);
234 static inline void data_lo()
236 PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT);
237 PS2_DATA_DDR |= (1<<PS2_DATA_BIT);
239 static inline void data_hi()
241 /* input with pull up */
242 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
243 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
245 static inline bool data_in()
247 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
248 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
250 return PS2_DATA_PIN&(1<<PS2_DATA_BIT);
253 static inline uint16_t wait_clock_lo(uint16_t us)
255 while (clock_in() && us) { asm(""); _delay_us(1); us--; }
258 static inline uint16_t wait_clock_hi(uint16_t us)
260 while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
263 static inline uint16_t wait_data_lo(uint16_t us)
265 while (data_in() && us) { asm(""); _delay_us(1); us--; }
268 static inline uint16_t wait_data_hi(uint16_t us)
270 while (!data_in() && us) { asm(""); _delay_us(1); us--; }
274 /* idle state that device can send */
275 static inline void idle(void)
281 /* inhibit device to send */
282 static inline void inhibit(void)
289 /*--------------------------------------------------------------------
290 * Ring buffer to store scan codes from keyboard
291 *------------------------------------------------------------------*/
293 static uint8_t pbuf[PBUF_SIZE];
294 static uint8_t pbuf_head = 0;
295 static uint8_t pbuf_tail = 0;
296 static inline void pbuf_enqueue(uint8_t data)
303 uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
304 if (next != pbuf_tail) {
305 pbuf[pbuf_head] = data;
308 debug("pbuf: full\n");
313 static inline uint8_t pbuf_dequeue(void)
319 if (pbuf_head != pbuf_tail) {
320 val = pbuf[pbuf_tail];
321 pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;