514
CHAPTER 27 REAL TIME CLOCK
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Auto-calibration
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Recommended Procedure of transition to and from auto-calibration:
1) Writing "1" to RTCCRH:PAU.
2) Transition to calibration mode.
3) Writing "0" to RTCCRH:PAU after transition from auto-calibration.
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Limitation:
If user want to transit to power save mode, auto-calibration must be completed. Writing "0" to
CALCR:CALEN can stop auto-calibration process.
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Operation of second counter and prescaler
Figure 27.5-1 operation of second counter and prescaler
In manual calibration or auto-calibration function, writing data to frequency fine-tuning register (FFTR)
can correct the clock error. It can be expained by the operation of second counter and prescaler. For
example, writing 8’H02 to FFTR, prescaler value change to 7FFD by using the equation 7FFF-offset
value(FFTR). When the counter value matches the prescaler value, the second counter increase one.
Prescaler value: 7FFF + offset value(FFTR)
(positive FFTR value)
Prescaler value: 7FFF - offset value(FFTR)
(negative FFTR value)
Prescaler value
time
FFTR
write 02 to FFTR value
write FE to FFTR value
7FFF
0000
FFTR value:2
000000H
SEC
8001
000001H
FFTR value:0H
7FFD
000002H
FFTR value:FEH (-2d)
trigger & increase 1 in sec counter
8'H00
8'H02
8'HFE
Summary of Contents for F2 MC-8FX Family
Page 2: ......
Page 4: ......
Page 34: ...20 CHAPTER 1 DESCRIPTION ...
Page 38: ...24 CHAPTER 2 HANDLING DEVICES ...
Page 39: ...25 CHAPTER 3 MEMORY SPACE This chapter describes memory space 3 1 Memory Space 3 2 Memory Map ...
Page 56: ...42 CHAPTER 5 CPU ...
Page 73: ...59 CHAPTER 6 CLOCK CONTROLLER ...
Page 96: ...82 CHAPTER 6 CLOCK CONTROLLER ...
Page 104: ...90 CHAPTER 7 RESET ...
Page 105: ...91 CHAPTER 8 INTERRUPTS This chapter explains the interrupts 8 1 Interrupts ...
Page 174: ...160 CHAPTER 10 TIMEBASE TIMER ...
Page 184: ...170 CHAPTER 10 TIMEBASE TIMER ...
Page 218: ...204 CHAPTER 13 WATCH PRESCALER ...
Page 257: ...243 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 261: ...247 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 288: ...274 CHAPTER 16 8 16 BIT COMPOSITE TIMER ...
Page 301: ...287 CHAPTER 17 16 BIT PPG TIMER ...
Page 316: ...302 CHAPTER 17 16 BIT PPG TIMER ...
Page 382: ...368 CHAPTER 21 UART SIO DEDICATED BAUD RATE GENERATOR ...
Page 390: ...376 CHAPTER 22 I2C ...
Page 395: ...381 CHAPTER 22 I2C ...
Page 399: ...385 CHAPTER 22 I2C ...
Page 430: ...416 CHAPTER 23 10 BIT A D CONVERTER ...
Page 476: ...462 CHAPTER 24 LCD CONTROLLER ...
Page 482: ...468 CHAPTER 25 LOW VOLTAGE DETECTION RESET CIRCUIT ...
Page 494: ...480 CHAPTER 26 CLOCK SUPERVISOR ...
Page 507: ...493 CHAPTER 27 REAL TIME CLOCK ...
Page 523: ...509 CHAPTER 27 REAL TIME CLOCK ...
Page 532: ...518 CHAPTER 27 REAL TIME CLOCK ...
Page 536: ...522 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 554: ...540 CHAPTER 28 256 KBIT FLASH MEMORY ...
Page 564: ...550 CHAPTER 29 EXAMPLE OF SERIAL PROGRAMMING CONNECTION ...
Page 595: ...581 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 596: ...582 INDEX Index ...
Page 597: ...583 INDEX ...
Page 600: ...586 Pin Function Index ...
Page 602: ......