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70095677 PH |
1 | /****************************************************************************** |
2 | * | |
3 | * Trennfix firmware - mm_switch.c | |
4 | * | |
5 | * Maerklin Motorola switch command receiver | |
6 | * | |
7 | * Copyright (C) 2017 Philipp Hachtmann | |
8 | * | |
9 | * This program is free software: you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation, either version 3 of the License, or | |
12 | * (at your option) any later version. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
21 | * | |
22 | *****************************************************************************/ | |
23 | ||
24 | #include <stdio.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | ||
28 | #include <avr/io.h> | |
29 | #include <avr/eeprom.h> | |
30 | #include <avr/interrupt.h> | |
31 | #include <avr/pgmspace.h> | |
32 | ||
33 | #include <util/delay.h> | |
34 | #include <stdint.h> | |
35 | ||
36 | #include "hardware.h" | |
37 | #include "mm_switch.h" | |
38 | ||
39 | #define DEBUG_TIMEOUT | |
40 | #ifdef DEBUG_TIMEOUT | |
41 | #define MON(val) setpin(PIN_DRIVE, val) | |
42 | #else | |
43 | #define MON(xx) ({0;}) | |
44 | #endif | |
45 | ||
46 | ||
47 | /* | |
48 | * Lookup decoder number. | |
49 | * | |
50 | */ | |
51 | static uint8_t lookup_decoder(uint8_t mm_byte) | |
52 | { | |
53 | switch(mm_byte) { | |
54 | /* 0x00 is invalid */ | |
55 | case 0xc0: return 1; | |
56 | case 0x80: return 2; | |
57 | case 0x30: return 3; | |
58 | case 0xf0: return 4; | |
59 | case 0xb0: return 5; | |
60 | case 0x20: return 6; | |
61 | case 0xe0: return 7; | |
62 | case 0xa0: return 8; | |
63 | ||
64 | case 0x0c: return 9; | |
65 | case 0xcc: return 10; | |
66 | case 0x8c: return 11; | |
67 | case 0x3c: return 12; | |
68 | case 0xfc: return 13; | |
69 | case 0xbc: return 14; | |
70 | case 0x2c: return 15; | |
71 | case 0xec: return 16; | |
72 | case 0xac: return 17; | |
73 | ||
74 | case 0x08: return 18; | |
75 | case 0xc8: return 19; | |
76 | case 0x88: return 20; | |
77 | case 0x38: return 21; | |
78 | case 0xf8: return 22; | |
79 | case 0xb8: return 23; | |
80 | case 0x28: return 24; | |
81 | case 0xe8: return 25; | |
82 | ||
83 | default: | |
84 | return 0; | |
85 | } | |
86 | } | |
87 | ||
88 | static uint8_t lookup_command(uint8_t mm_byte) | |
89 | { | |
90 | switch(mm_byte) { | |
91 | case 0xc3: return 1; | |
92 | case 0x03: return 2; | |
93 | case 0xf3: return 3; | |
94 | case 0x33: return 4; | |
95 | case 0xcf: return 5; | |
96 | case 0x0f: return 6; | |
97 | case 0xff: return 7; | |
98 | case 0x3f: return 8; | |
99 | default: | |
100 | return 0; | |
101 | } | |
102 | } | |
103 | ||
104 | static void mm_switch_init(void) | |
105 | { | |
106 | /* Get rid of the 1/8 clock prescaler */ | |
107 | CLKPR = (1 << CLKPCE); | |
108 | CLKPR = 0; | |
109 | ||
110 | GIMSK |= _BV(PCIE); /* Enable pin change interrupt */ | |
111 | PCMSK = _BV(PCINT4); /* PB4, Rail sense input */ | |
112 | ||
113 | TCCR0A = 0; /* This is normal mode */ | |
114 | TCCR0B = 0; /* Timer off */ | |
115 | TIMSK |= _BV(OCIE0A); /* Get a match interrupt */ | |
116 | TIMSK |= _BV(TOV0); /* Overflow interrupt */ | |
117 | ||
118 | /* We need 13 + 45 us delay, That's 464 clocks @8MHz*/ | |
119 | OCR0A = 91; /* Prescaler 8 is used */ | |
120 | ||
121 | /* Timer 1 for timeout */ | |
122 | /* We set it to 1024us by prescaler 64 and running full 256 */ | |
123 | TCCR1 = 7; | |
124 | TIMSK |= _BV(TOIE1); /* Overflow interrupt */ | |
125 | } | |
126 | ||
127 | ||
128 | static volatile uint8_t shift_sub; | |
129 | static volatile uint8_t shift_zero; | |
130 | static volatile uint8_t shift_decoder; | |
131 | static volatile uint8_t shift_sub_first; | |
132 | static volatile uint8_t shift_decoder_first; | |
133 | ||
134 | /* We will shift from right to left. | |
135 | * XXXXXXXX XX XXXXXXXX | |
136 | * shift_decoder shift_zero shift_sub | |
137 | * | |
138 | * The bits 7 downto 2 of shift_zero are ignored. | |
139 | */ | |
140 | ||
141 | volatile uint8_t bitno = 0; | |
142 | ||
143 | static void trigger(void) | |
144 | { | |
145 | setpin(PIN_DRIVE, 1); | |
146 | _delay_us(10); | |
147 | setpin(PIN_DRIVE, 0); | |
148 | } | |
149 | ||
150 | enum recstate { | |
151 | IDLE = 0, | |
152 | FIRST_FAST_SAMPLE, | |
153 | FIRST_SLOW_SAMPLE, /* If clock arrives, we stay on the fast path! */ | |
154 | FAST_SAMPLE, | |
155 | FAST_WAIT_FOR_CLOCK, | |
156 | SLOW_SAMPLE, | |
157 | SLOW_WAIT_FOR_CLOCK, | |
158 | }; | |
159 | ||
160 | static enum recstate recstate = IDLE; | |
161 | ||
162 | static inline void shift(uint8_t value) | |
163 | { | |
164 | shift_decoder <<= 1; | |
165 | if (shift_zero & 2) | |
166 | shift_decoder |= 1; | |
167 | shift_zero <<= 1; | |
168 | if (shift_sub & 0x80) | |
169 | shift_zero |= 1; | |
170 | shift_sub <<= 1; | |
171 | if (value) | |
172 | shift_sub |= 1; | |
173 | } | |
174 | ||
175 | ||
176 | ISR(TIMER0_COMPA_vect) { | |
177 | ||
178 | static uint8_t patience = 0; | |
179 | ||
180 | switch(recstate) { | |
181 | case FIRST_FAST_SAMPLE: | |
182 | recstate = FIRST_SLOW_SAMPLE; | |
183 | TSTART_CLK_TO_SAMPLE_FAST; /* Will not run out in fast! */ | |
184 | break; | |
185 | ||
186 | case FIRST_SLOW_SAMPLE: | |
187 | bitno = 0; | |
188 | ||
189 | case SLOW_SAMPLE: | |
190 | recstate = SLOW_WAIT_FOR_CLOCK; | |
191 | TSTART_CLK_TO_SAMPLE_SLOW; | |
192 | break; | |
193 | ||
194 | case FAST_SAMPLE: | |
195 | recstate = FAST_WAIT_FOR_CLOCK; | |
196 | TSTART_CLK_TO_SAMPLE_FAST; | |
197 | break; | |
198 | ||
199 | case FAST_WAIT_FOR_CLOCK: /* A timeout! */ | |
200 | if (patience) { | |
201 | patience--; | |
202 | TSTART_CLK_TO_SAMPLE_FAST; | |
203 | return; | |
204 | } | |
205 | recstate = IDLE; | |
206 | TSTOP; | |
207 | return; | |
208 | ||
209 | case SLOW_WAIT_FOR_CLOCK: | |
210 | if (patience) { | |
211 | patience--; | |
212 | TSTART_CLK_TO_SAMPLE_SLOW; | |
213 | return; | |
214 | } | |
215 | TSTOP; | |
216 | recstate = IDLE; | |
217 | return; | |
218 | } | |
219 | ||
220 | shift(MM_SENSE); | |
221 | bitno++; | |
222 | ||
223 | if (bitno == 18) { /* Save first received word */ | |
224 | shift_sub_first = shift_sub; | |
225 | shift_decoder_first = shift_decoder; | |
226 | patience = 18; | |
227 | ||
228 | } | |
229 | if (bitno == 36) { | |
230 | if ((shift_sub == shift_sub_first) && | |
231 | (shift_decoder == shift_decoder_first)) { | |
232 | uint8_t decoder = lookup_decoder(shift_decoder); | |
233 | uint8_t command = lookup_command(shift_sub); | |
234 | if (recstate == SLOW_WAIT_FOR_CLOCK) | |
235 | trigger(); | |
236 | if (decoder) { | |
237 | /* Congratulations, we have a valid command */ | |
238 | if (recstate == FAST_WAIT_FOR_CLOCK) { | |
239 | // trigger(); | |
240 | mm_switch_command(decoder, command); | |
241 | } | |
242 | } | |
243 | } | |
244 | } | |
245 | } | |
246 | ||
247 | ISR(BADISR_vect) | |
248 | { | |
249 | while(1) { | |
250 | /* | |
251 | setpin(PIN_LED, 1); | |
252 | _delay_ms(30); | |
253 | setpin(PIN_LED, 0); | |
254 | _delay_ms(30); | |
255 | setpin(PIN_LED, 1); | |
256 | _delay_ms(30); | |
257 | setpin(PIN_LED, 0); | |
258 | _delay_ms(2000); | |
259 | */ | |
260 | } | |
261 | } | |
262 | ||
263 | ISR(TIM0_OVF_vect) | |
264 | { | |
265 | return; | |
266 | while(1) { | |
267 | setpin(PIN_LED, 1); | |
268 | _delay_ms(30); | |
269 | setpin(PIN_LED, 0); | |
270 | _delay_ms(300); | |
271 | } | |
272 | ||
273 | } | |
274 | ||
275 | ||
276 | /* Pin change interrupt vector */ | |
277 | void mm_pinchange_handler(void) | |
278 | { | |
279 | static uint8_t sense_last; | |
280 | ||
281 | if (MM_SENSE == sense_last) | |
282 | return; | |
283 | sense_last = MM_SENSE; | |
284 | if (!sense_last) | |
285 | return; | |
286 | ||
287 | switch(recstate) { | |
288 | case IDLE: | |
289 | bitno = 0; | |
290 | recstate = FIRST_FAST_SAMPLE; | |
291 | TSTART_CLK_TO_SAMPLE_FAST; | |
292 | break; | |
293 | case FIRST_SLOW_SAMPLE: | |
294 | recstate = FAST_SAMPLE; | |
295 | TSTART_CLK_TO_SAMPLE_FAST; | |
296 | break; | |
297 | case FAST_WAIT_FOR_CLOCK: | |
298 | recstate = FAST_SAMPLE; | |
299 | TSTART_CLK_TO_SAMPLE_FAST; | |
300 | break; | |
301 | case SLOW_WAIT_FOR_CLOCK: | |
302 | recstate = SLOW_SAMPLE; | |
303 | TSTART_CLK_TO_SAMPLE_SLOW; | |
304 | break; | |
305 | ||
306 | /* Not expected */ | |
307 | case FIRST_FAST_SAMPLE: | |
308 | case FAST_SAMPLE: | |
309 | case SLOW_SAMPLE: | |
310 | default: | |
311 | break; | |
312 | } | |
313 | } | |
314 | ||
315 | /****************************************************************************** | |
316 | * The end :-) | |
317 | */ | |
318 | ||
319 | ||
320 |