17.4 Operational Description
The RTC incorporates a second counter that generates a 1Hz signal from a 32.768 kHz signal.
The second counter operation must be taken into account when using the RTC.
Note:
After reset, a low-speed clock stops oscillation. XT1 and XT2 ports are initialized to PP0 and PP1 ports. Re-set-
up RTC register.
17.4.1 Reading clock data
1. Using 1Hz interrupt
The 1Hz interrupt is generated being synchronized with counting up of the second counter.
Data can be read correctly if reading data after 1Hz interrupt occurred.
2. Using pair reading
There is a possibility that the clock data may be read incorrectly if the internal counter operates car-
ry during reading. To ensure correct data reading, read the clock data twice as shown below. A
pair of data read successively needs to match.
Start
RTCPAGER<PAGE> = "0",
then select PAGE0
Clock data reading
(1st)
Clock data reading
(2nd)
1st data = 2nd data
End
NO
YES
Figure 17-2 Flowchart of the clock data reading
17.4.2 Writing clock data
A carry during writing ruins correct data writing. The following procedure ensures the correct data writing.
1. Using 1 Hz interrupt
The 1Hz interrupt is generated by being synchronized with counting up of the second counter. If
data is written in the time between 1Hz interrupt and subsequent one second count, it completes cor-
rectly.
2. Resetting counter
TMPM3V6/M3V4
17. Real Time Clock (RTC)
17.4 Operational Description
Page 410
2019-02-06
Содержание TMPM3V4
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Страница 2: ... 2019 Toshiba Electronic Devices Storage Corporation ...
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Страница 52: ...TMPM3V6 M3V4 3 Processor Core 3 6 Exclusive access Page 30 2019 02 06 ...
Страница 148: ...TMPM3V6 M3V4 7 Exceptions 7 6 Exception Interrupt Related Registers Page 126 2019 02 06 ...
Страница 178: ...TMPM3V6 M3V4 9 Input Output port 9 2 Block Diagrams of Ports Page 156 2019 02 06 ...
Страница 206: ...TMPM3V6 M3V4 10 16 bit Timer Event Counters TMRB 10 7 Applications using the Capture Function Page 184 2019 02 06 ...
Страница 232: ...TMPM3V6 M3V4 11 Universal Asynchronous Receiver Transmitter Circuit UART 11 4 Operation Description Page 210 2019 02 06 ...
Страница 354: ...TMPM3V6 M3V4 14 Synchronous Serial Port SSP 14 6 Frame Format Page 332 2019 02 06 ...
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Страница 420: ...TMPM3V6 M3V4 16 Analog Digital Converter ADC 16 6 Timing chart of AD conversion Page 398 2019 02 06 ...
Страница 462: ...TMPM3V6 M3V4 21 Watchdog Timer WDT 21 5 Control register Page 440 2019 02 06 ...
Страница 510: ...TMPM3V6 M3V4 22 Flash Memory Operation 22 4 Programming in the User Boot Mode Page 488 2019 02 06 ...
Страница 538: ...TMPM3V6 M3V4 25 Electrical Characteristics 25 7 Recommended Oscillation Circuit Page 516 2019 02 06 ...
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