{{ message }}
forked from JChristensen/MCP79412RTC
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathMCP79412RTC.cpp
More file actions
598 lines (538 loc) · 25.7 KB
/
Copy pathMCP79412RTC.cpp
File metadata and controls
598 lines (538 loc) · 25.7 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
/*----------------------------------------------------------------------*
* MCP79412RTC.cpp - Arduino library for the Microchip MCP79412 *
* Real-Time Clock. This library is intended for use with the Arduino *
* Time.h library, http://www.arduino.cc/playground/Code/Time *
* *
* This library is a drop-in replacement for the DS1307RTC.h library *
* by Michael Margolis that is supplied with the Arduino Time library *
* above. To change from using a DS1307 RTC to an MCP79412 RTC, it is *
* only necessary to change the #include statement to include this *
* library instead of DS1307RTC.h. *
* *
* In addition, this library implements functions to support the *
* additional features of the MCP79412. *
* *
* Jack Christensen 29Jul2012 *
* *
* This work is licensed under the Creative Commons Attribution- *
* ShareAlike 3.0 Unported License. To view a copy of this license, *
* visit http://creativecommons.org/licenses/by-sa/3.0/ or send a *
* letter to Creative Commons, 171 Second Street, Suite 300, *
* San Francisco, California, 94105, USA. *
*----------------------------------------------------------------------*/
#include <Wire.h>
#include <TinyWireM.h>
#include "MCP79412RTC.h"
/*----------------------------------------------------------------------*
* Constructor. *
*----------------------------------------------------------------------*/
MCP79412RTC::MCP79412RTC()
{
i2cBegin();
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it as a time_t value. *
* Returns a zero value if RTC not present (I2C I/O error). *
*----------------------------------------------------------------------*/
time_t MCP79412RTC::get()
{
tmElements_t tm;
if ( read(tm) )
return( makeTime(tm) );
else
return 0;
}
/*----------------------------------------------------------------------*
* Set the RTC to the given time_t value. *
*----------------------------------------------------------------------*/
void MCP79412RTC::set(time_t t)
{
tmElements_t tm;
breakTime(t, tm);
write(tm);
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it in a tmElements_t *
* structure. Returns false if RTC not present (I2C I/O error). *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::read(tmElements_t &tm)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
if (i2cEndTransmission() != 0) {
return false;
}
else {
//request 7 bytes (secs, min, hr, dow, date, mth, yr)
i2cRequestFrom(RTC_ADDR, tmNbrFields);
tm.Second = bcd2dec(i2cRead() & ~_BV(ST));
tm.Minute = bcd2dec(i2cRead());
tm.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
tm.Wday = i2cRead() & ~(_BV(OSCON) | _BV(VBAT) | _BV(VBATEN)); //mask off OSCON, VBAT, VBATEN bits
tm.Day = bcd2dec(i2cRead());
tm.Month = bcd2dec(i2cRead() & ~_BV(LP)); //mask off the leap year bit
tm.Year = y2kYearToTm(bcd2dec(i2cRead()));
return true;
}
}
/*----------------------------------------------------------------------*
* Set the RTC's time from a tmElements_t structure. *
*----------------------------------------------------------------------*/
void MCP79412RTC::write(tmElements_t &tm)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
i2cWrite((uint8_t)0x00); //stops the oscillator (Bit 7, ST == 0)
i2cWrite(dec2bcd(tm.Minute));
i2cWrite(dec2bcd(tm.Hour)); //sets 24 hour format (Bit 6 == 0)
i2cWrite(tm.Wday | _BV(VBATEN)); //enable battery backup operation
i2cWrite(dec2bcd(tm.Day));
i2cWrite(dec2bcd(tm.Month));
i2cWrite(dec2bcd(tmYearToY2k(tm.Year)));
i2cEndTransmission();
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
i2cWrite(dec2bcd(tm.Second) | _BV(ST)); //set the seconds and start the oscillator (Bit 7, ST == 1)
i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Write a single byte to RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramWrite(byte addr, byte value)
{
ramWrite(addr, &value, 1);
}
/*----------------------------------------------------------------------*
* Write multiple bytes to RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
* Number of bytes (nBytes) must be between 1 and 31 (Wire library *
* limitation). *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramWrite(byte addr, byte *values, byte nBytes)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite(addr);
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Read a single byte from RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
*----------------------------------------------------------------------*/
byte MCP79412RTC::ramRead(byte addr)
{
byte value;
ramRead(addr, &value, 1);
return value;
}
/*----------------------------------------------------------------------*
* Read multiple bytes from RTC RAM. *
* Valid address range is 0x00 - 0x5F, no checking. *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramRead(byte addr, byte *values, byte nBytes)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite(addr);
i2cEndTransmission();
i2cRequestFrom( (uint8_t)RTC_ADDR, nBytes );
for (byte i=0; i<nBytes; i++) values[i] = i2cRead();
}
/*----------------------------------------------------------------------*
* Write a single byte to Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
*----------------------------------------------------------------------*/
void MCP79412RTC::sramWrite(byte addr, byte value)
{
ramWrite( (addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, &value, 1 );
}
/*----------------------------------------------------------------------*
* Write multiple bytes to Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
* Number of bytes (nBytes) must be between 1 and 31 (Wire library *
* limitation). *
* Invalid values for nBytes, or combinations of addr and nBytes *
* that would result in addressing past the last byte of SRAM will *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::sramWrite(byte addr, byte *values, byte nBytes)
{
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
if (nBytes >= 1 && (addr + nBytes) <= SRAM_SIZE) {
#else
if (nBytes >= 1 && nBytes <= (BUFFER_LENGTH - 1) && (addr + nBytes) <= SRAM_SIZE) {
#endif
ramWrite( (addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, values, nBytes );
}
}
/*----------------------------------------------------------------------*
* Read a single byte from Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
*----------------------------------------------------------------------*/
byte MCP79412RTC::sramRead(byte addr)
{
byte value;
ramRead( (addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, &value, 1 );
return value;
}
/*----------------------------------------------------------------------*
* Read multiple bytes from Static RAM. *
* Address (addr) is constrained to the range (0, 63). *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
* Invalid values for nBytes, or combinations of addr and *
* nBytes that would result in addressing past the last byte of SRAM *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::sramRead(byte addr, byte *values, byte nBytes)
{
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
if (nBytes >= 1 && (addr + nBytes) <= SRAM_SIZE) {
#else
if (nBytes >= 1 && nBytes <= BUFFER_LENGTH && (addr + nBytes) <= SRAM_SIZE) {
#endif
ramRead((addr & (SRAM_SIZE - 1) ) + SRAM_START_ADDR, values, nBytes);
}
}
/*----------------------------------------------------------------------*
* Write a single byte to EEPROM. *
* Address (addr) is constrained to the range (0, 127). *
* Can't leverage page write function because a write can't start *
* mid-page. *
*----------------------------------------------------------------------*/
void MCP79412RTC::eepromWrite(byte addr, byte value)
{
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite( addr & (EEPROM_SIZE - 1) );
i2cWrite(value);
i2cEndTransmission();
eepromWait();
}
/*----------------------------------------------------------------------*
* Write a page (or less) to EEPROM. An EEPROM page is 8 bytes. *
* Address (addr) should be a page start address (0, 8, ..., 120), but *
* is ruthlessly coerced into a valid value. *
* Number of bytes (nBytes) must be between 1 and 8, other values *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::eepromWrite(byte addr, byte *values, byte nBytes)
{
if (nBytes >= 1 && nBytes <= EEPROM_PAGE_SIZE) {
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite( addr & ~(EEPROM_PAGE_SIZE - 1) & (EEPROM_SIZE - 1) );
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
i2cEndTransmission();
eepromWait();
}
}
/*----------------------------------------------------------------------*
* Read a single byte from EEPROM. *
* Address (addr) is constrained to the range (0, 127). *
*----------------------------------------------------------------------*/
byte MCP79412RTC::eepromRead(byte addr)
{
byte value;
eepromRead( addr & (EEPROM_SIZE - 1), &value, 1 );
return value;
}
/*----------------------------------------------------------------------*
* Read multiple bytes from EEPROM. *
* Address (addr) is constrained to the range (0, 127). *
* Number of bytes (nBytes) must be between 1 and 32 (Wire library *
* limitation). *
* Invalid values for addr or nBytes, or combinations of addr and *
* nBytes that would result in addressing past the last byte of EEPROM *
* result in no action. *
*----------------------------------------------------------------------*/
void MCP79412RTC::eepromRead(byte addr, byte *values, byte nBytes)
{
#if defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
if (nBytes >= 1 && (addr + nBytes) <= EEPROM_SIZE) {
#else
if (nBytes >= 1 && nBytes <= BUFFER_LENGTH && (addr + nBytes) <= EEPROM_SIZE) {
#endif
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite( addr & (EEPROM_SIZE - 1) );
i2cEndTransmission();
i2cRequestFrom( (uint8_t)EEPROM_ADDR, nBytes );
for (byte i=0; i<nBytes; i++) values[i] = i2cRead();
}
}
/*----------------------------------------------------------------------*
* Wait for EEPROM write to complete. *
*----------------------------------------------------------------------*/
byte MCP79412RTC::eepromWait(void)
{
byte waitCount = 0;
byte txStatus;
do
{
++waitCount;
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite((uint8_t)0);
txStatus = i2cEndTransmission();
} while (txStatus != 0);
return waitCount;
}
/*----------------------------------------------------------------------*
* Read the calibration register. *
* The calibration value is not a twos-complement number. The MSB is *
* the sign bit, and the 7 LSBs are an unsigned number, so we convert *
* it and return it to the caller as a regular twos-complement integer. *
*----------------------------------------------------------------------*/
int MCP79412RTC::calibRead(void)
{
byte val = ramRead(CALIB_REG);
if ( val & 0x80 ) return -(val & 0x7F);
else return val;
}
/*----------------------------------------------------------------------*
* Write the calibration register. *
* Calibration value must be between -127 and 127, others result *
* in no action. See note above on the format of the calibration value. *
*----------------------------------------------------------------------*/
void MCP79412RTC::calibWrite(int value)
{
byte calibVal;
if (value >= -127 && value <= 127) {
calibVal = abs(value);
if (value < 0) calibVal += 128;
ramWrite(CALIB_REG, calibVal);
}
}
/*----------------------------------------------------------------------*
* Read the unique ID. *
* Caller must provide an 8-byte array to contain the results. *
*----------------------------------------------------------------------*/
void MCP79412RTC::idRead(byte *uniqueID)
{
i2cBeginTransmission(EEPROM_ADDR);
i2cWrite(UNIQUE_ID_ADDR);
i2cEndTransmission();
i2cRequestFrom( EEPROM_ADDR, UNIQUE_ID_SIZE );
for (byte i=0; i<UNIQUE_ID_SIZE; i++) uniqueID[i] = i2cRead();
}
/*----------------------------------------------------------------------*
* Check to see if a power failure has occurred. If so, returns TRUE *
* as the function value, and returns the power down and power up *
* timestamps. After returning the time stamps, the RTC's timestamp *
* registers are cleared and the VBAT bit which indicates a power *
* failure is reset. *
* *
* Note that the power down and power up timestamp registers do not *
* contain values for seconds or for the year. The returned time stamps *
* will therefore contain the current year from the RTC. However, there *
* is a chance that a power outage spans from one year to the next. *
* If we find the power down timestamp to be later (larger) than the *
* power up timestamp, we will assume this has happened, and well *
* subtract one year from the power down timestamp. *
* *
* Still, there is an assumption that the timestamps are being read *
* in the same year as that when the power up occurred. *
* *
* Finally, note that once the RTC records a power outage, it must be *
* cleared before another will be recorded. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::powerFail(time_t *powerDown, time_t *powerUp)
{
byte day, yr; //copies of the RTC Day and Year registers
tmElements_t dn, up; //power down and power up times
ramRead(DAY_REG, &day, 1);
ramRead(YEAR_REG, &yr, 1);
yr = y2kYearToTm(bcd2dec(yr));
if ( day & _BV(VBAT) ) {
i2cBeginTransmission(RTC_ADDR);
i2cWrite(PWRDWN_TS_REG);
i2cEndTransmission();
i2cRequestFrom(RTC_ADDR, TIMESTAMP_SIZE); //read both timestamp registers, 8 bytes total
dn.Second = 0;
dn.Minute = bcd2dec(i2cRead());
dn.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
dn.Day = bcd2dec(i2cRead());
dn.Month = bcd2dec(i2cRead() & 0x1F); //mask off the day, we don't need it
dn.Year = yr; //assume current year
up.Second = 0;
up.Minute = bcd2dec(i2cRead());
up.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
up.Day = bcd2dec(i2cRead());
up.Month = bcd2dec(i2cRead() & 0x1F); //mask off the day, we don't need it
up.Year = yr; //assume current year
*powerDown = makeTime(dn);
*powerUp = makeTime(up);
//clear the VBAT bit, which causes the RTC hardware to clear the timestamps too.
//I suppose there is a risk here that the day has changed since we read it,
//but the Day of Week is actually redundant data and the makeTime() function
//does not use it. This could be an issue if someone is reading the RTC
//registers directly, but as this library is meant to be used with the Time library,
//and also because we don't provide a method to read the RTC clock/calendar
//registers directly, we won't lose any sleep about it at this point unless
//some issue is actually brought to our attention ;-)
day &= ~_BV(VBAT);
ramWrite(DAY_REG, &day , 1);
//adjust the powerDown timestamp if needed (see notes above)
if (*powerDown > *powerUp) {
--dn.Year;
*powerDown = makeTime(dn);
}
return true;
}
else
return false;
}
/*----------------------------------------------------------------------*
* Enable or disable the square wave output. *
*----------------------------------------------------------------------*/
void MCP79412RTC::squareWave(uint8_t freq)
{
uint8_t ctrlReg;
ramRead(CTRL_REG, &ctrlReg, 1);
if (freq > 3) {
ctrlReg &= ~_BV(SQWE);
}
else {
ctrlReg = (ctrlReg & 0xF8) | _BV(SQWE) | freq;
}
ramWrite(CTRL_REG, &ctrlReg, 1);
}
/*----------------------------------------------------------------------*
* Set an alarm time. Sets the alarm registers only, does not enable *
* the alarm. See enableAlarm(). *
*----------------------------------------------------------------------*/
void MCP79412RTC::setAlarm(uint8_t alarmNumber, time_t alarmTime)
{
tmElements_t tm;
uint8_t day; //need to preserve bits in the day (of week) register
alarmNumber &= 0x01; //ensure a valid alarm number
ramRead( ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG) , &day, 1);
breakTime(alarmTime, tm);
i2cBeginTransmission(RTC_ADDR);
i2cWrite( ALM0_REG + alarmNumber * (ALM1_REG - ALM0_REG) );
i2cWrite(dec2bcd(tm.Second));
i2cWrite(dec2bcd(tm.Minute));
i2cWrite(dec2bcd(tm.Hour)); //sets 24 hour format (Bit 6 == 0)
i2cWrite( (day & 0xF8) + tm.Wday );
i2cWrite(dec2bcd(tm.Day));
i2cWrite(dec2bcd(tm.Month));
i2cEndTransmission();
}
/*----------------------------------------------------------------------*
* Enable or disable an alarm, and set the trigger criteria, *
* e.g. match only seconds, only minutes, entire time and date, etc. *
*----------------------------------------------------------------------*/
void MCP79412RTC::enableAlarm(uint8_t alarmNumber, uint8_t alarmType)
{
uint8_t day; //alarm day register has config & flag bits
uint8_t ctrl; //control register has alarm enable bits
alarmNumber &= 0x01; //ensure a valid alarm number
ramRead(CTRL_REG, &ctrl, 1);
if (alarmType < ALM_DISABLE) {
ramRead(ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
day = ( day & 0x87 ) | alarmType << 4; //reset interrupt flag, OR in the config bits
ramWrite(ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
ctrl |= _BV(ALM0 + alarmNumber); //enable the alarm
}
else {
ctrl &= ~(_BV(ALM0 + alarmNumber)); //disable the alarm
}
ramWrite(CTRL_REG, &ctrl, 1);
}
/*----------------------------------------------------------------------*
* Returns true or false depending on whether the given alarm has been *
* triggered, and resets the alarm "interrupt" flag. This is not a real *
* interrupt, just a bit that's set when an alarm is triggered. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::alarm(uint8_t alarmNumber)
{
uint8_t day; //alarm day register has config & flag bits
alarmNumber &= 0x01; //ensure a valid alarm number
ramRead( ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
if (day & _BV(ALMIF)) {
day &= ~_BV(ALMIF); //turn off the alarm "interrupt" flag
ramWrite( ALM0_DAY + alarmNumber * (ALM1_REG - ALM0_REG), &day, 1);
return true;
}
else
return false;
}
/*----------------------------------------------------------------------*
* Sets the logic level on the MFP when it's not being used as a *
* square wave or alarm output. The default is HIGH. *
*----------------------------------------------------------------------*/
void MCP79412RTC::out(boolean level)
{
uint8_t ctrlReg;
ramRead(CTRL_REG, &ctrlReg, 1);
if (level)
ctrlReg |= _BV(OUT);
else
ctrlReg &= ~_BV(OUT);
ramWrite(CTRL_REG, &ctrlReg, 1);
}
/*----------------------------------------------------------------------*
* Specifies the logic level on the Multi-Function Pin (MFP) when an *
* alarm is triggered. The default is LOW. When both alarms are *
* active, the two are ORed together to determine the level of the MFP. *
* With alarm polarity set to LOW (the default), this causes the MFP *
* to go low only when BOTH alarms are triggered. With alarm polarity *
* set to HIGH, the MFP will go high when EITHER alarm is triggered. *
* *
* Note that the state of the MFP is independent of the alarm *
* "interrupt" flags, and the alarm() function will indicate when an *
* alarm is triggered regardless of the polarity. *
*----------------------------------------------------------------------*/
void MCP79412RTC::alarmPolarity(boolean polarity)
{
uint8_t alm0Day;
ramRead(ALM0_DAY, &alm0Day, 1);
if (polarity)
alm0Day |= _BV(OUT);
else
alm0Day &= ~_BV(OUT);
ramWrite(ALM0_DAY, &alm0Day, 1);
}
/*----------------------------------------------------------------------*
* Check to see if the RTC's oscillator is started (ST bit in seconds *
* register). Returns true if started. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::isRunning(void)
{
i2cBeginTransmission(RTC_ADDR);
i2cWrite((uint8_t)TIME_REG);
i2cEndTransmission();
//request just the seconds register
i2cRequestFrom(RTC_ADDR, 1);
return i2cRead() & _BV(ST);
}
/*----------------------------------------------------------------------*
* Set or clear the VBATEN bit. Setting the bit powers the clock and *
* SRAM from the backup battery when Vcc falls. Note that setting the *
* time via set() or write() sets the VBATEN bit. *
*----------------------------------------------------------------------*/
void MCP79412RTC::vbaten(boolean enable)
{
uint8_t day;
ramRead(DAY_REG, &day, 1);
if (enable)
day |= _BV(VBATEN);
else
day &= ~_BV(VBATEN);
ramWrite(DAY_REG, &day, 1);
return;
}
/*----------------------------------------------------------------------*
* Decimal-to-BCD conversion *
*----------------------------------------------------------------------*/
uint8_t MCP79412RTC::dec2bcd(uint8_t num)
{
return ((num / 10 * 16) + (num % 10));
}
/*----------------------------------------------------------------------*
* BCD-to-Decimal conversion *
*----------------------------------------------------------------------*/
uint8_t MCP79412RTC::bcd2dec(uint8_t num)
{
return ((num / 16 * 10) + (num % 16));
}
MCP79412RTC RTC = MCP79412RTC(); //instantiate an RTC object
You can’t perform that action at this time.