{{ 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
363 lines (323 loc) · 15.6 KB
/
Copy pathMCP79412RTC.cpp
File metadata and controls
363 lines (323 loc) · 15.6 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
/*----------------------------------------------------------------------*
* 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 "MCP79412RTC.h"
/*----------------------------------------------------------------------*
* Constructor. *
*----------------------------------------------------------------------*/
MCP79412RTC::MCP79412RTC()
{
Wire.begin();
}
/*----------------------------------------------------------------------*
* Read the current time from the RTC and return it as a time_t value. *
*----------------------------------------------------------------------*/
time_t MCP79412RTC::get()
{
tmElements_t tm;
read(tm);
return(makeTime(tm));
}
/*----------------------------------------------------------------------*
* 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. *
*----------------------------------------------------------------------*/
void MCP79412RTC::read(tmElements_t &tm)
{
Wire.beginTransmission(RTC_ADDR);
i2cWrite(TIME_REG);
Wire.endTransmission();
//request 7 bytes (secs, min, hr, dow, date, mth, yr)
Wire.requestFrom(RTC_ADDR, tmNbrFields);
tm.Second = bcd2dec(i2cRead() & ~_BV(ST));
tm.Minute = bcd2dec(i2cRead());
tm.Hour = bcd2dec(i2cRead() & ~_BV(HR1224)); //assumes 24hr clock
tm.Wday = bcd2dec(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()));
}
/*----------------------------------------------------------------------*
* Set the RTC's time from a tmElements_t structure. *
*----------------------------------------------------------------------*/
void MCP79412RTC::write(tmElements_t &tm)
{
Wire.beginTransmission(RTC_ADDR);
i2cWrite(TIME_REG);
i2cWrite(0x00); //stops the oscillator (Bit 7, ST == 0)
i2cWrite(dec2bcd(tm.Minute));
i2cWrite(dec2bcd(tm.Hour)); //sets 24 hour format (Bit 6 == 0)
i2cWrite(dec2bcd(tm.Wday) | _BV(VBATEN)); //enable battery backup operation
i2cWrite(dec2bcd(tm.Day));
i2cWrite(dec2bcd(tm.Month));
i2cWrite(dec2bcd(tmYearToY2k(tm.Year)));
Wire.endTransmission();
Wire.beginTransmission(RTC_ADDR);
i2cWrite(TIME_REG);
i2cWrite(dec2bcd(tm.Second) | _BV(ST)); //set the seconds and start the oscillator (Bit 7, ST == 1)
Wire.endTransmission();
}
/*----------------------------------------------------------------------*
* 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 *
* has a limitation of 31 bytes). *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramWrite(byte addr, byte *values, byte nBytes)
{
Wire.beginTransmission(RTC_ADDR);
i2cWrite(addr);
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
Wire.endTransmission();
}
/*----------------------------------------------------------------------*
* 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 31 (Wire library *
* has a limitation of 31 bytes). *
*----------------------------------------------------------------------*/
void MCP79412RTC::ramRead(byte addr, byte *values, byte nBytes)
{
Wire.beginTransmission(RTC_ADDR);
i2cWrite(addr);
Wire.endTransmission();
Wire.requestFrom( (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 *
* has a limitation of 31 bytes). *
* 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 (nBytes >= 1 && nBytes <= I2C_BYTE_LIMIT && (addr + nBytes) <= SRAM_SIZE) {
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 31 (Wire library *
* has a limitation of 31 bytes). *
* Invalid values for addr or 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 (nBytes >= 1 && nBytes <= I2C_BYTE_LIMIT && (addr + nBytes) <= SRAM_SIZE) {
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)
{
Wire.beginTransmission(EEPROM_ADDR);
i2cWrite( addr & (EEPROM_SIZE - 1) );
i2cWrite(value);
Wire.endTransmission();
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) {
Wire.beginTransmission(EEPROM_ADDR);
i2cWrite( addr & ~(EEPROM_PAGE_SIZE - 1) & (EEPROM_SIZE - 1) );
for (byte i=0; i<nBytes; i++) i2cWrite(values[i]);
Wire.endTransmission();
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 31 (Wire library *
* has a limitation of 31 bytes). *
* 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 (nBytes >= 1 && nBytes <= I2C_BYTE_LIMIT && (addr + nBytes) <= EEPROM_SIZE) {
Wire.beginTransmission(EEPROM_ADDR);
i2cWrite( addr & (EEPROM_SIZE - 1) );
Wire.endTransmission();
Wire.requestFrom( (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;
Wire.beginTransmission(EEPROM_ADDR);
i2cWrite(0);
txStatus = Wire.endTransmission();
} 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)
{
Wire.beginTransmission(EEPROM_ADDR);
i2cWrite(UNIQUE_ID_ADDR);
Wire.endTransmission();
Wire.requestFrom( EEPROM_ADDR, UNIQUE_ID_SIZE );
for (byte i=0; i<UNIQUE_ID_SIZE; i++) uniqueID[i] = i2cRead();
}
/*----------------------------------------------------------------------*
* Check to see if the RTC's oscillator is started (ST bit in seconds *
* register). Returns true if started. *
*----------------------------------------------------------------------*/
boolean MCP79412RTC::oscStarted(void)
{
Wire.beginTransmission(RTC_ADDR);
i2cWrite(TIME_REG);
Wire.endTransmission();
//request just the seconds register
Wire.requestFrom(RTC_ADDR, 1);
return i2cRead() & _BV(ST);
}
/*----------------------------------------------------------------------*
* 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.