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) {
194 // NOTE: to read data line early as possible:
195 // write naked ISR with asembly code to read the line and call C func to do other job?
199 dbit = IBMPC_DATA_PIN&(1<<IBMPC_DATA_BIT);
200 isr_data = isr_data>>1;
201 if (dbit) isr_data |= 0x8000;
204 // 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
205 // -----------------------------------------------------
206 // Initial: *1 0 0 0 0 0 0 0 | 0 0 0 0 0 0 0 0
207 // XT IBM: b7 b6 b5 b4 b3 b2 b1 b0 | s1 s0 *1 0 0 0 0 0 after receiving **
208 // XT Clone: b7 b6 b5 b4 b3 b2 b1 b0 | s1 *1 0 0 0 0 0 0 after receiving
209 // AT: st pr b7 b6 b5 b4 b3 b2 | b1 b0 s0 *1 0 0 0 0 after receiving
210 // AT**: pr b7 b6 b5 b4 b3 b2 b1 | b0 s0 *1 0 0 0 0 0 before stop bit **
212 // x x x x x x x x | 0 0 0 0 0 0 0 0 midway(0-7 bits received)
213 // x x x x x x x x | 1 0 0 0 0 0 0 0 midway(8 bits received)
214 // x x x x x x x x | 0 1 0 0 0 0 0 0 XT IBM-midway or AT-midway
215 // x x x x x x x x | 1 1 0 0 0 0 0 0 XT Clone-done
216 // x x x x x x x x | 0 0 1 0 0 0 0 0 AT-midway
217 // x x x x x x x x | 1 0 1 0 0 0 0 0 XT IBM-done or AT-midway **
218 // x x x x x x x x | x 1 1 0 0 0 0 0 illegal
219 // x x x x x x x x | x x 0 1 0 0 0 0 AT-done
220 // x x x x x x x x | x x 1 1 0 0 0 0 illegal
221 // other states than avobe illegal
223 // **: AT can take same as end sate of XT IBM(1010 000) when b0 is 1,
224 // to discriminate between them we will have to wait a while for stop bit.
226 // mask for isr_data:
227 // 0x00A0(1010 0000) when XT IBM
228 // 0x00C0(1100 0000) when XT Clone
229 // 0x0010(xx01 0000) when AT
231 switch (isr_data & 0xFF) {
241 recv_data = (isr_data>>8) & 0xFF;
247 // wait for rising and falling edge of AT stop bit
248 while (!(IBMPC_CLOCK_PIN&(1<<IBMPC_CLOCK_BIT)) && us) { wait_us(1); us--; }
249 while ( IBMPC_CLOCK_PIN&(1<<IBMPC_CLOCK_BIT) && us) { wait_us(1); us--; }
252 // found stop bit: return immediately and process the stop bit in ISR
258 recv_data = (isr_data>>8) & 0xFF;
268 recv_data = (isr_data>>6) & 0xFF;
277 default: // xxxx_oooo(any 1 in low nibble)
278 recv_data = isr_data;
282 // TODO: buffer for recv_data
283 isr_data = 0x8000; // clear to next data
287 /* send LED state to keyboard */
288 void ibmpc_host_set_led(uint8_t led)
290 ibmpc_host_send(0xED);
291 ibmpc_host_send(led);