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Diffstat (limited to 'tmk_core/protocol/ps2_usart.c')
-rw-r--r--tmk_core/protocol/ps2_usart.c226
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diff --git a/tmk_core/protocol/ps2_usart.c b/tmk_core/protocol/ps2_usart.c
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index 5f7008369..000000000
--- a/tmk_core/protocol/ps2_usart.c
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1/*
2Copyright 2010,2011,2012,2013 Jun WAKO <wakojun@gmail.com>
3
4This software is licensed with a Modified BSD License.
5All of this is supposed to be Free Software, Open Source, DFSG-free,
6GPL-compatible, and OK to use in both free and proprietary applications.
7Additions and corrections to this file are welcome.
8
9
10Redistribution and use in source and binary forms, with or without
11modification, are permitted provided that the following conditions are met:
12
13* Redistributions of source code must retain the above copyright
14 notice, this list of conditions and the following disclaimer.
15
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
19 distribution.
20
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.
24
25THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
26AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
29LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35POSSIBILITY OF SUCH DAMAGE.
36*/
37
38/*
39 * PS/2 protocol USART version
40 */
41
42#include <stdbool.h>
43#include <avr/interrupt.h>
44#include <util/delay.h>
45#include "ps2.h"
46#include "ps2_io.h"
47#include "print.h"
48
49#ifndef PS2_CLOCK_DDR
50# define PS2_CLOCK_DDR PORTx_ADDRESS(PS2_CLOCK_PIN)
51#endif
52#ifndef PS2_CLOCK_BIT
53# define PS2_CLOCK_BIT (PS2_CLOCK_PIN & 0xF)
54#endif
55#ifndef PS2_DATA_DDR
56# define PS2_DATA_DDR PORTx_ADDRESS(PS2_DATA_PIN)
57#endif
58#ifndef PS2_DATA_BIT
59# define PS2_DATA_BIT (PS2_DATA_PIN & 0xF)
60#endif
61
62#define WAIT(stat, us, err) \
63 do { \
64 if (!wait_##stat(us)) { \
65 ps2_error = err; \
66 goto ERROR; \
67 } \
68 } while (0)
69
70uint8_t ps2_error = PS2_ERR_NONE;
71
72static inline uint8_t pbuf_dequeue(void);
73static inline void pbuf_enqueue(uint8_t data);
74static inline bool pbuf_has_data(void);
75static inline void pbuf_clear(void);
76
77void ps2_host_init(void) {
78 idle(); // without this many USART errors occur when cable is disconnected
79 PS2_USART_INIT();
80 PS2_USART_RX_INT_ON();
81 // POR(150-2000ms) plus BAT(300-500ms) may take 2.5sec([3]p.20)
82 //_delay_ms(2500);
83}
84
85uint8_t ps2_host_send(uint8_t data) {
86 bool parity = true;
87 ps2_error = PS2_ERR_NONE;
88
89 PS2_USART_OFF();
90
91 /* terminate a transmission if we have */
92 inhibit();
93 _delay_us(100); // [4]p.13
94
95 /* 'Request to Send' and Start bit */
96 data_lo();
97 clock_hi();
98 WAIT(clock_lo, 10000, 10); // 10ms [5]p.50
99
100 /* Data bit[2-9] */
101 for (uint8_t i = 0; i < 8; i++) {
102 _delay_us(15);
103 if (data & (1 << i)) {
104 parity = !parity;
105 data_hi();
106 } else {
107 data_lo();
108 }
109 WAIT(clock_hi, 50, 2);
110 WAIT(clock_lo, 50, 3);
111 }
112
113 /* Parity bit */
114 _delay_us(15);
115 if (parity) {
116 data_hi();
117 } else {
118 data_lo();
119 }
120 WAIT(clock_hi, 50, 4);
121 WAIT(clock_lo, 50, 5);
122
123 /* Stop bit */
124 _delay_us(15);
125 data_hi();
126
127 /* Ack */
128 WAIT(data_lo, 50, 6);
129 WAIT(clock_lo, 50, 7);
130
131 /* wait for idle state */
132 WAIT(clock_hi, 50, 8);
133 WAIT(data_hi, 50, 9);
134
135 idle();
136 PS2_USART_INIT();
137 PS2_USART_RX_INT_ON();
138 return ps2_host_recv_response();
139ERROR:
140 idle();
141 PS2_USART_INIT();
142 PS2_USART_RX_INT_ON();
143 return 0;
144}
145
146uint8_t ps2_host_recv_response(void) {
147 // Command may take 25ms/20ms at most([5]p.46, [3]p.21)
148 uint8_t retry = 25;
149 while (retry-- && !pbuf_has_data()) {
150 _delay_ms(1);
151 }
152 return pbuf_dequeue();
153}
154
155uint8_t ps2_host_recv(void) {
156 if (pbuf_has_data()) {
157 ps2_error = PS2_ERR_NONE;
158 return pbuf_dequeue();
159 } else {
160 ps2_error = PS2_ERR_NODATA;
161 return 0;
162 }
163}
164
165ISR(PS2_USART_RX_VECT) {
166 // TODO: request RESEND when error occurs?
167 uint8_t error = PS2_USART_ERROR; // USART error should be read before data
168 uint8_t data = PS2_USART_RX_DATA;
169 if (!error) {
170 pbuf_enqueue(data);
171 } else {
172 xprintf("PS2 USART error: %02X data: %02X\n", error, data);
173 }
174}
175
176/* send LED state to keyboard */
177void ps2_host_set_led(uint8_t led) {
178 ps2_host_send(0xED);
179 ps2_host_send(led);
180}
181
182/*--------------------------------------------------------------------
183 * Ring buffer to store scan codes from keyboard
184 *------------------------------------------------------------------*/
185#define PBUF_SIZE 32
186static uint8_t pbuf[PBUF_SIZE];
187static uint8_t pbuf_head = 0;
188static uint8_t pbuf_tail = 0;
189static inline void pbuf_enqueue(uint8_t data) {
190 uint8_t sreg = SREG;
191 cli();
192 uint8_t next = (pbuf_head + 1) % PBUF_SIZE;
193 if (next != pbuf_tail) {
194 pbuf[pbuf_head] = data;
195 pbuf_head = next;
196 } else {
197 print("pbuf: full\n");
198 }
199 SREG = sreg;
200}
201static inline uint8_t pbuf_dequeue(void) {
202 uint8_t val = 0;
203
204 uint8_t sreg = SREG;
205 cli();
206 if (pbuf_head != pbuf_tail) {
207 val = pbuf[pbuf_tail];
208 pbuf_tail = (pbuf_tail + 1) % PBUF_SIZE;
209 }
210 SREG = sreg;
211
212 return val;
213}
214static inline bool pbuf_has_data(void) {
215 uint8_t sreg = SREG;
216 cli();
217 bool has_data = (pbuf_head != pbuf_tail);
218 SREG = sreg;
219 return has_data;
220}
221static inline void pbuf_clear(void) {
222 uint8_t sreg = SREG;
223 cli();
224 pbuf_head = pbuf_tail = 0;
225 SREG = sreg;
226}
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