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 busywait version
43 #include <util/delay.h>
48 #define WAIT(stat, us, err) do { \
49 if (!wait_##stat(us)) { \
56 uint8_t ps2_error = PS2_ERR_NONE;
59 void ps2_host_init(void)
61 // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
67 uint8_t ps2_host_send(uint8_t data)
70 ps2_error = PS2_ERR_NONE;
72 /* terminate a transmission if we have */
74 _delay_us(100); // 100us [4]p.13, [5]p.50
76 /* 'Request to Send' and Start bit */
79 WAIT(clock_lo, 10000, 10); // 10ms [5]p.50
82 for (uint8_t i = 0; i < 8; i++) {
90 WAIT(clock_hi, 50, 2);
91 WAIT(clock_lo, 50, 3);
96 if (parity) { data_hi(); } else { data_lo(); }
97 WAIT(clock_hi, 50, 4);
98 WAIT(clock_lo, 50, 5);
105 WAIT(data_lo, 50, 6);
106 WAIT(clock_lo, 50, 7);
108 /* wait for idle state */
109 WAIT(clock_hi, 50, 8);
110 WAIT(data_hi, 50, 9);
113 return ps2_host_recv_response();
119 /* receive data when host want else inhibit communication */
120 uint8_t ps2_host_recv_response(void)
122 // Command may take 25ms/20ms at most([5]p.46, [3]p.21)
123 // 250 * 100us(wait for start bit in ps2_host_recv)
127 data = ps2_host_recv();
128 } while (try-- && ps2_error);
132 /* called after start bit comes */
133 uint8_t ps2_host_recv(void)
137 ps2_error = PS2_ERR_NONE;
139 /* release lines(idle state) */
143 WAIT(clock_lo, 100, 1); // TODO: this is enough?
145 WAIT(clock_hi, 50, 3);
148 for (uint8_t i = 0; i < 8; i++) {
149 WAIT(clock_lo, 50, 4);
154 WAIT(clock_hi, 50, 5);
158 WAIT(clock_lo, 50, 6);
159 if (data_in() != parity) {
160 ps2_error = PS2_ERR_PARITY;
163 WAIT(clock_hi, 50, 7);
166 WAIT(clock_lo, 50, 8);
168 WAIT(clock_hi, 50, 10);
173 if (ps2_error > PS2_ERR_STARTBIT3) {
174 xprintf("x%02X\n", ps2_error);
180 /* send LED state to keyboard */
181 void ps2_host_set_led(uint8_t led)