trennfix/sw: Single timer single delay solution seems to work
[eisenbahn.git] / trennfix / sw / mm / src / mm_switch.c
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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
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36#include <config/hardware.h>
37#include <mm/mm_switch.h>
70095677 38
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39/*
40 * Private data types
41 */
42
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43
44/*
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45 *
46 * Check for stuff we need
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47 *
48 */
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49#if !defined(MM_TSTART_FAST) || !defined(MM_TSTART_SLOW) || !defined(MM_TSTOP) \
50 || !defined(MM_SENSE) || !defined(MM_TIMER_INT_VECT)
56b25f8b 51
93cb14d4 52#error Missing timer start macro MM_TSTART_FAST!
56b25f8b 53
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54#endif
55
56/*
57 * Private global variables
58 */
93cb14d4 59
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60#ifndef MM_USE_REGISTER_VARS
61
62static volatile uint8_t bitno = 0;
63static uint8_t shift_command;
64static uint8_t shift_function;
65static uint8_t shift_address;
66static enum mm_recstate recstate = MM_IDLE;
67
68#endif
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69
70/*
71 * Lookup trinary nibble
72 *
73 * This was implemented using a switch statement before.
74 * Changing the lookup to a table did only add two bytes
75 * of memory and saved ca. 50 bytes program memory.
76 */
77static const uint8_t nibble_table[16]={
78 [0x0] = 0,
79 [0xc] = 1,
80 [0x8] = 2,
81 [0x3] = 3,
82 [0xf] = 4,
83 [0xb] = 5,
84 [0x2] = 6,
85 [0xe] = 7,
86 [0xa] = 8
87};
88#define lookup_nibble(nibble) nibble_table[nibble & 0xf]
89
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90static uint8_t lookup_decoder(uint8_t mm_byte)
91{
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92 uint8_t low;
93 uint8_t high;
94 if (mm_byte == 0)
93cb14d4 95 return 80;
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96 low = lookup_nibble(mm_byte >> 4);
97 high = lookup_nibble(mm_byte & 0xf);
98 if (!low)
70095677 99 return 0;
56b25f8b 100 return 9 * high + low;
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101}
102
7c08d02a 103static uint8_t lookup_command(uint8_t mm_command)
70095677 104{
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105 uint8_t res;
106 /*
107 * Check for aabbccdd condition
108 *
109 * a a b b c c d d mm_command
110 * XOR a b b c c d d 0 mm_command << 1
111 * Mask 1 0 1 0 1 0 1 0 0xaa
112 *
113 * Must be zero!
114 *
115 */
116
117 if ((mm_command ^ (mm_command << 1)) & 0xaa)
70095677 118 return 0;
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119 /*
120 * Protocol differences:
121 * =====================
122 *
123 * I have an old "central control" 6022 and a "control unit" 6021
124 * for measurements and test. It is assumed that the 6022 outputs
125 * old MM1 format while the 6021 definitively outputs MM2 telegrams.
126 *
127 * In MM1, switch commands are different from MM2 with respect what
128 * happens if you release a button.
129 *
130 * When you press a button, both protocols send
131 *
132 * <aaaaaaaa><00><aabbcc11>
133 *
134 * where a = 1, b = 2, c = 4 and the keys are numerated from 0 to 7
135 * in the order 1 red, 1 green, 2 red, 2 green and so on.
136 *
137 * The last two bits correspond to "on" state of the button/coil.
138 *
139 * When a key is released under MM1 protocol, the sequence sent is
140 * analogue to the button down sequence:
141 *
142 * <aaaaaaaa><00><aabbcc00> where abc again represents the button's
143 * address and the last bits now signal "off".
144 *
145 * MM2 handles this differently:
146 * Whenever any key from the addressed decoder is released, the sequence
147 * <aaaaaaaa>00<00000000> is sent - not only for key 0, but for all
148 * keys!
149 *
150 * While MM1 presents the theoretical possibility to press several keys
151 * independently and simultaneously (which my keyboard does NOT
152 * support), MM2 supports only one key at a time (besides strange
153 * sequences like "one down, another down, all up"...
154 *
155 * A decoder that strictly adheres to the MM1 standard would not work
156 * properly with MM2 control units. As far as I know all K83/K84
157 * decoders always worked with MM2 control units. That means that
158 * they reduce the commands to the possibilities of MM2 from the
159 * beginning.
160 *
161 * Possible use cases for the old protocol button release commands:
162 * - Determine if the protocol is MM1 or MM2
163 * - Implement hidden evil features into the controller which can
164 * only be summoned by old MM1 gear or selfmade control telegram
165 * generators.
166 *
167 * What this code now actually does:
168 * =================================
169 *
170 * When key pressed (aabbcc11), it will send out the key number in the
171 * range 1-8 and 0 if it gets any key up command and therefore ignore
172 * the key number if it is transmitted with the key up command.
173 *
174 */
175 if (!(mm_command & 0x01))
176 res = 0;
177 else
178 res = (mm_command & 0x80) * 1 + (mm_command & 0x20) * 0x02
179 + (mm_command & 0x08) * 0x04 + 1;
180 return res;
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181}
182
7c08d02a 183
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184/* We will shift from right to left.
185 * XXXXXXXX XX XXXXXXXX
56b25f8b 186 * shift_address shift_function shift_command
70095677 187 *
56b25f8b 188 * The bits 7 downto 2 of shift_function are ignored.
70095677 189 */
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190#define SAVE_ANOTHER_40_BYTES
191#ifdef SAVE_ANOTHER_40_BYTES
70095677 192
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193void shift(uint8_t value)
194{
195 asm("ror %[val] ; Shift value right into carry\n\t"
196 "rol %[cmd] ; and shift to command reg\n\t"
197 "mov __tmp_reg__, %[func] ; save function value \n\t"
198 "rol %[func] ; Shift up function value\n\t"
199 "ror __tmp_reg__ ; shift bit 1\n\t"
200 "ror __tmp_reg__ ; down to carry\n\t"
201 "rol %[addr] ; And we're at the address\n\t"
202 : [cmd] "=r" (shift_command), [func] "=r" (shift_function),
203 [addr] "=r" (shift_address)
204 : "0" (shift_command), "1" (shift_function),
205 "2" (shift_address), [val] "r" (value)
206 );
207}
208
209#else /* This is what we do to shift */
210
211void shift(uint8_t value)
70095677 212{
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213 shift_address <<= 1;
214 if (shift_function & 2)
215 shift_address |= 1;
216 shift_function <<= 1;
217 if (shift_command & 0x80)
218 shift_function |= 1;
219 shift_command <<= 1;
70095677 220 if (value)
56b25f8b 221 shift_command |= 1;
70095677 222}
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223#endif
224
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225static volatile uint8_t mm_rec_tolerated_timeouts;
226
70095677 227
93cb14d4 228ISR(MM_TIMER_INT_VECT) {
70095677 229
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230 static volatile uint8_t shift_command_first;
231 static volatile uint8_t shift_function_first;
232 static volatile uint8_t shift_address_first;
233 uint8_t address;
234 uint8_t command;
235
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236 MM_TSTART_FAST;
237
93cb14d4 238#ifdef MM_FILTER_REPEATED
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239 static uint8_t address_last = 0xff;
240 static uint8_t function_last = 0xff;
241 static uint8_t command_last = 0xff;
93cb14d4 242#endif
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243
244 switch(recstate) {
9c77e706 245
7c08d02a 246 case MM_FIRST_FAST_SAMPLE:
9c77e706 247 recstate = MM_FIRST_SLOW_SAMPLE ;
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248 break;
249
7c08d02a 250 case MM_FIRST_SLOW_SAMPLE:
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251 bitno = 0;
252
7c08d02a 253 case MM_SLOW_SAMPLE:
9c77e706 254 recstate = MM_SLOW_WAIT_FOR_CLOCK_DELAY;
70095677 255 break;
9c77e706 256
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257 case MM_FAST_SAMPLE:
258 recstate = MM_FAST_WAIT_FOR_CLOCK;
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259 break;
260
7c08d02a 261 case MM_FAST_WAIT_FOR_CLOCK: /* A timeout! */
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262 if (mm_rec_tolerated_timeouts) {
263 mm_rec_tolerated_timeouts--;
264 } else {
265 recstate = MM_IDLE;
266
70095677 267 }
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268 return;
269
270 case MM_SLOW_SAMPLE_DELAY:
271 recstate = MM_SLOW_SAMPLE;
272 return;
273
274 case MM_SLOW_WAIT_FOR_CLOCK_DELAY:
275 recstate = MM_SLOW_WAIT_FOR_CLOCK;
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276 return;
277
7c08d02a 278 case MM_SLOW_WAIT_FOR_CLOCK:
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279 if (mm_rec_tolerated_timeouts) {
280 mm_rec_tolerated_timeouts--;
281 recstate = MM_SLOW_WAIT_FOR_CLOCK_DELAY;
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282 return;
283 }
56b25f8b 284 default:
7c08d02a 285 recstate = MM_IDLE;
9c77e706 286 case MM_IDLE:
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287 return;
288 }
289
290 shift(MM_SENSE);
291 bitno++;
56b25f8b 292
70095677 293 if (bitno == 18) { /* Save first received word */
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294 shift_address_first = shift_address;
295 shift_function_first = shift_function;
296 shift_command_first = shift_command;
9c77e706 297 mm_rec_tolerated_timeouts = 18;
70095677 298 }
56b25f8b 299
70095677 300 if (bitno == 36) {
56b25f8b 301 if ((shift_command == shift_command_first) &&
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302 (shift_address == shift_address_first) &&
303 (shift_function == shift_function_first)) {
304
305#ifdef MM_FILTER_REPEATED
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306 if ((shift_address != address_last) || (shift_command != command_last) ||
307 shift_function != function_last) {
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308#endif
309 address = lookup_decoder(shift_address);
56b25f8b 310
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311 if (recstate == MM_SLOW_WAIT_FOR_CLOCK_DELAY) {
312 trigger();
93cb14d4 313 mm_switch_drive(address, shift_function, shift_command);
7c08d02a 314 } else if (recstate == MM_FAST_WAIT_FOR_CLOCK) {
9c77e706 315 trigger();
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316 command = lookup_command(shift_command);
317 mm_switch_command(address, command);
70095677 318 }
93cb14d4 319#ifdef MM_FILTER_REPEATED
70095677 320 }
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321 address_last = shift_address;
322 function_last = shift_function;
323 command_last = shift_command;
324#endif
70095677 325 }
56b25f8b 326
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327 }
328}
329
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330//void __attribute((weak)) mm_switch_drive(uint8_t address, uint8_t function, uint8_t command);
331
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332ISR(BADISR_vect)
333{
334 while(1) {
335 /*
336 setpin(PIN_LED, 1);
337 _delay_ms(30);
338 setpin(PIN_LED, 0);
339 _delay_ms(30);
340 setpin(PIN_LED, 1);
341 _delay_ms(30);
342 setpin(PIN_LED, 0);
343 _delay_ms(2000);
344 */
345 }
346}
347
348ISR(TIM0_OVF_vect)
349{
350 return;
351 while(1) {
56b25f8b 352 setpin(PIN_LED, 1);
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353 _delay_ms(30);
354 setpin(PIN_LED, 0);
355 _delay_ms(300);
356 }
357
358}
359
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360/* Pin change interrupt vector */
361void mm_pinchange_handler(void)
362{
363 static uint8_t sense_last;
364
365 if (MM_SENSE == sense_last)
366 return;
367 sense_last = MM_SENSE;
368 if (!sense_last)
369 return;
56b25f8b 370
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371 MM_TSTART_FAST;
372
70095677 373 switch(recstate) {
7c08d02a 374 case MM_IDLE:
70095677 375 bitno = 0;
7c08d02a 376 recstate = MM_FIRST_FAST_SAMPLE;
70095677 377 break;
9c77e706 378
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379 case MM_FIRST_SLOW_SAMPLE:
380 recstate = MM_FAST_SAMPLE;
70095677 381 break;
9c77e706 382
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383 case MM_FAST_WAIT_FOR_CLOCK:
384 recstate = MM_FAST_SAMPLE;
9c77e706 385 mm_rec_tolerated_timeouts = 0;
70095677 386 break;
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387
388 case MM_SLOW_WAIT_FOR_CLOCK_DELAY: /* If clock comes early */
389 recstate = MM_SLOW_WAIT_FOR_CLOCK;
390 break;
391
7c08d02a 392 case MM_SLOW_WAIT_FOR_CLOCK:
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393 recstate = MM_SLOW_SAMPLE_DELAY;
394 mm_rec_tolerated_timeouts = 0;
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395 break;
396
397 /* Not expected */
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398 case MM_FIRST_FAST_SAMPLE:
399 case MM_FAST_SAMPLE:
400 case MM_SLOW_SAMPLE:
9c77e706 401 recstate = MM_IDLE;
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402 default:
403 break;
404 }
405}
406
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407void __attribute__((weak))mm_switch_drive(uint8_t decoder, uint8_t function,
408 uint8_t command)
409{
410 while(1);
411}
412
413void __attribute__((weak))mm_switch_command(uint8_t address, uint8_t command)
414{
415}
416
417
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418/******************************************************************************
419 * The end :-)
420 */
421
422
423