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
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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 static inline uint8_t pbuf_dequeue(void);
99 static inline void pbuf_enqueue(uint8_t data);
102 void ps2_host_init(void)
108 PS2_USART_RX_INT_ON();
111 uint8_t ps2_host_send(uint8_t data)
115 ps2_error = PS2_ERR_NONE;
120 /* terminate a transmission if we have */
127 WAIT(clock_lo, 15000, 1);
129 for (uint8_t i = 0; i < 8; i++) {
137 WAIT(clock_hi, 50, 2);
138 WAIT(clock_lo, 50, 3);
142 if (parity) { data_hi(); } else { data_lo(); }
143 WAIT(clock_hi, 50, 4);
144 WAIT(clock_lo, 50, 5);
149 WAIT(data_lo, 50, 6);
150 WAIT(clock_lo, 50, 7);
152 /* wait for idle state */
153 WAIT(clock_hi, 50, 8);
154 WAIT(data_hi, 50, 9);
156 res = ps2_host_recv_response();
160 PS2_USART_RX_INT_ON();
164 // Do polling data from keyboard to get response to last command.
165 uint8_t ps2_host_recv_response(void)
169 PS2_USART_RX_POLL_ON();
170 while (!PS2_USART_RX_READY)
172 data = PS2_USART_RX_DATA;
178 uint8_t ps2_host_recv(void)
180 return pbuf_dequeue();
183 ISR(PS2_USART_RX_VECT)
186 uint8_t error = PS2_USART_ERROR;
187 uint8_t data = PS2_USART_RX_DATA;
196 /* send LED state to keyboard */
197 void ps2_host_set_led(uint8_t led)
199 // send 0xED then keyboard keeps waiting for next LED data
200 // and keyboard does not send any scan codes during waiting.
201 // If fail to send LED data keyboard looks like being freezed.
203 while (retry-- && ps2_host_send(PS2_SET_LED) != PS2_ACK)
206 while (retry-- && ps2_host_send(led) != PS2_ACK)
211 /*--------------------------------------------------------------------
213 *------------------------------------------------------------------*/
214 static inline void clock_lo()
216 PS2_CLOCK_PORT &= ~(1<<PS2_CLOCK_BIT);
217 PS2_CLOCK_DDR |= (1<<PS2_CLOCK_BIT);
219 static inline void clock_hi()
221 /* input with pull up */
222 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
223 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
225 static inline bool clock_in()
227 PS2_CLOCK_DDR &= ~(1<<PS2_CLOCK_BIT);
228 PS2_CLOCK_PORT |= (1<<PS2_CLOCK_BIT);
230 return PS2_CLOCK_PIN&(1<<PS2_CLOCK_BIT);
232 static inline void data_lo()
234 PS2_DATA_PORT &= ~(1<<PS2_DATA_BIT);
235 PS2_DATA_DDR |= (1<<PS2_DATA_BIT);
237 static inline void data_hi()
239 /* input with pull up */
240 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
241 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
243 static inline bool data_in()
245 PS2_DATA_DDR &= ~(1<<PS2_DATA_BIT);
246 PS2_DATA_PORT |= (1<<PS2_DATA_BIT);
248 return PS2_DATA_PIN&(1<<PS2_DATA_BIT);
251 static inline uint16_t wait_clock_lo(uint16_t us)
253 while (clock_in() && us) { asm(""); _delay_us(1); us--; }
256 static inline uint16_t wait_clock_hi(uint16_t us)
258 while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
261 static inline uint16_t wait_data_lo(uint16_t us)
263 while (data_in() && us) { asm(""); _delay_us(1); us--; }
266 static inline uint16_t wait_data_hi(uint16_t us)
268 while (!data_in() && us) { asm(""); _delay_us(1); us--; }
272 /* idle state that device can send */
273 static inline void idle(void)
279 /* inhibit device to send */
280 static inline void inhibit(void)
287 /*--------------------------------------------------------------------
288 * Ring buffer to store scan codes from keyboard
289 *------------------------------------------------------------------*/
291 static uint8_t pbuf[PBUF_SIZE];
292 static uint8_t pbuf_head = 0;
293 static uint8_t pbuf_tail = 0;
294 static inline void pbuf_enqueue(uint8_t data)
301 uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
302 if (next != pbuf_tail) {
303 pbuf[pbuf_head] = data;
306 debug("pbuf: full\n");
311 static inline uint8_t pbuf_dequeue(void)
317 if (pbuf_head != pbuf_tail) {
318 val = pbuf[pbuf_tail];
319 pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;