2 Copyright 2010,2011,2012,2013 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 * PS/2 protocol USART version
44 #include <avr/interrupt.h>
45 #include <util/delay.h>
50 #define WAIT(stat, us, err) do { \
51 if (!wait_##stat(us)) { \
58 uint8_t ps2_error = PS2_ERR_NONE;
61 static inline uint8_t pbuf_dequeue(void);
62 static inline void pbuf_enqueue(uint8_t data);
63 static inline bool pbuf_has_data(void);
64 static inline void pbuf_clear(void);
67 void ps2_host_init(void)
69 idle(); // without this many USART errors occur when cable is disconnected
71 PS2_USART_RX_INT_ON();
72 // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
76 uint8_t ps2_host_send(uint8_t data)
79 ps2_error = PS2_ERR_NONE;
83 /* terminate a transmission if we have */
90 WAIT(clock_lo, 15000, 1);
92 for (uint8_t i = 0; i < 8; i++) {
100 WAIT(clock_hi, 50, 2);
101 WAIT(clock_lo, 50, 3);
105 if (parity) { data_hi(); } else { data_lo(); }
106 WAIT(clock_hi, 50, 4);
107 WAIT(clock_lo, 50, 5);
112 WAIT(data_lo, 50, 6);
113 WAIT(clock_lo, 50, 7);
115 /* wait for idle state */
116 WAIT(clock_hi, 50, 8);
117 WAIT(data_hi, 50, 9);
121 PS2_USART_RX_INT_ON();
122 return ps2_host_recv_response();
126 PS2_USART_RX_INT_ON();
130 // Do polling data from keyboard to get response to last command.
131 uint8_t ps2_host_recv_response(void)
134 while (retry-- && !pbuf_has_data()) {
135 _delay_ms(1); // without this delay it seems to fall into deadlock
137 return pbuf_dequeue();
140 uint8_t ps2_host_recv(void)
142 if (pbuf_has_data()) {
143 ps2_error = PS2_ERR_NONE;
144 return pbuf_dequeue();
146 ps2_error = PS2_ERR_NODATA;
151 ISR(PS2_USART_RX_VECT)
153 // TODO: request RESEND when error occurs?
154 uint8_t error = PS2_USART_ERROR; // USART error should be read before data
155 uint8_t data = PS2_USART_RX_DATA;
159 xprintf("PS2 USART error: %02X data: %02X\n", error, data);
163 /* send LED state to keyboard */
164 void ps2_host_set_led(uint8_t led)
171 /*--------------------------------------------------------------------
172 * Ring buffer to store scan codes from keyboard
173 *------------------------------------------------------------------*/
175 static uint8_t pbuf[PBUF_SIZE];
176 static uint8_t pbuf_head = 0;
177 static uint8_t pbuf_tail = 0;
178 static inline void pbuf_enqueue(uint8_t data)
182 uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
183 if (next != pbuf_tail) {
184 pbuf[pbuf_head] = data;
187 debug("pbuf: full\n");
192 static inline uint8_t pbuf_dequeue(void)
198 if (pbuf_head != pbuf_tail) {
199 val = pbuf[pbuf_tail];
200 pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;
206 static inline bool pbuf_has_data(void)
210 bool has_data = (pbuf_head != pbuf_tail);
214 static inline void pbuf_clear(void)
218 pbuf_head = pbuf_tail = 0;