2 Copyright 2010,2011,2012,2013,2019 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 * IBM PC keyboard protocol
43 #include <avr/interrupt.h>
44 #include <util/atomic.h>
52 #define WAIT(stat, us, err) do { \
53 if (!wait_##stat(us)) { \
61 static uint8_t buf[BUF_SIZE];
62 static ringbuf_t rb = {
66 .size_mask = BUF_SIZE - 1
69 volatile uint8_t ibmpc_protocol = IBMPC_PROTOCOL_AT;
70 volatile uint8_t ibmpc_error = IBMPC_ERR_NONE;
72 void ibmpc_host_init(void)
74 // initialize reset pin to HiZ
81 void ibmpc_host_enable(void)
87 void ibmpc_host_disable(void)
93 int16_t ibmpc_host_send(uint8_t data)
96 ibmpc_error = IBMPC_ERR_NONE;
98 if (ibmpc_protocol == IBMPC_PROTOCOL_XT) return -1;
100 dprintf("w%02X ", data);
104 /* terminate a transmission if we have */
106 wait_us(100); // 100us [4]p.13, [5]p.50
108 /* 'Request to Send' and Start bit */
111 WAIT(clock_lo, 10000, 1); // 10ms [5]p.50
114 for (uint8_t i = 0; i < 8; i++) {
122 WAIT(clock_hi, 50, 2);
123 WAIT(clock_lo, 50, 3);
128 if (parity) { data_hi(); } else { data_lo(); }
129 WAIT(clock_hi, 50, 4);
130 WAIT(clock_lo, 50, 5);
137 WAIT(data_lo, 50, 6);
138 WAIT(clock_lo, 50, 7);
140 /* wait for idle state */
141 WAIT(clock_hi, 50, 8);
142 WAIT(data_hi, 50, 9);
144 // clear buffer to get response correctly
146 ibmpc_host_isr_clear();
150 return ibmpc_host_recv_response();
152 ibmpc_error |= IBMPC_ERR_SEND;
159 * Receive data from keyboard with ISR
161 static volatile int16_t recv_data = -1;
162 static volatile uint16_t isr_data = 0x8000;
164 void ibmpc_host_isr_clear(void)
169 int16_t ibmpc_host_recv(void)
172 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
177 dprintf("r%04X ", data);
183 int16_t ibmpc_host_recv_response(void)
185 // Command may take 25ms/20ms at most([5]p.46, [3]p.21)
188 while (retry-- && (data = ibmpc_host_recv()) == -1) {
197 dbit = IBMPC_DATA_PIN&(1<<IBMPC_DATA_BIT);
198 isr_data = isr_data>>1;
199 if (dbit) isr_data |= 0x8000;
202 // 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
203 // -----------------------------------------------------
204 // Initial: *1 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0
205 // XT IBM: b7 b6 b5 b4 b3 b2 b1 b0 | s1 s0 *1 0 0 0 0 0 after receiving **
206 // XT Clone: b7 b6 b5 b4 b3 b2 b1 b0 | s1 *1 0 0 0 0 0 0 after receiving
207 // AT: st pr b7 b6 b5 b4 b3 b2 | b1 b0 s0 *1 0 0 0 0 after receiving
208 // AT**: pr b7 b6 b5 b4 b3 b2 b1 | b0 s0 *1 0 0 0 0 0 before stop bit **
210 // x x x x x x x x | 0 0 0 0 0 0 0 0 midway(0-7 bits received)
211 // x x x x x x x x | 1 0 0 0 0 0 0 0 midway(8 bits received)
212 // x x x x x x x x | 0 1 0 0 0 0 0 0 XT IBM-midway or AT-midway
213 // x x x x x x x x | 1 1 0 0 0 0 0 0 XT Clone-done
214 // x x x x x x x x | 0 0 1 0 0 0 0 0 AT-midway
215 // x x x x x x x x | 1 0 1 0 0 0 0 0 XT IBM-done or AT-midway **
216 // x x x x x x x x | x 1 1 0 0 0 0 0 illegal
217 // x x x x x x x x | x x 0 1 0 0 0 0 AT-done
218 // x x x x x x x x | x x 1 1 0 0 0 0 illegal
219 // other states than avobe illegal
221 // **: AT can take same as end sate of XT IBM(1010 000) when b0 is 1,
222 // to discriminate between them we will have to wait a while for stop bit.
224 // mask for isr_data:
225 // 0x00A0(1010 0000) when XT IBM
226 // 0x00C0(1100 0000) when XT Clone
227 // 0x0010(xx01 0000) when AT
229 switch (isr_data & 0xFF) {
239 recv_data = (isr_data>>8) & 0xFF;
243 // XT IBM-done or AT-midway
244 // wait and check for clock of AT stop bit
245 if (wait_clock_hi(100) && wait_clock_lo(100)) { // FIXME this makes ISR prologe long
250 recv_data = (isr_data>>8) & 0xFF;
259 recv_data = (isr_data>>6) & 0xFF;
268 default: // xxxx_oooo(any 1 in low nibble)
269 recv_data = isr_data;
273 // TODO: buffer for recv_data
274 isr_data = 0x8000; // clear to next data
278 /* send LED state to keyboard */
279 void ibmpc_host_set_led(uint8_t led)
281 ibmpc_host_send(0xED);
282 ibmpc_host_send(led);