SH7708 datasheet(351/633 Pages) RENESAS

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Bit 2—30-Second Adjustment (ADJ): When 1 is written to the ADJ bit, times of 29 seconds or

less will be rounded to 00 seconds and 30 seconds or more to 1 minute. The divider circuit will be

simultaneously reset. This bit always reads 0.

Bit 2: ADJ

Description

Runs normally.

(Initial value)

1 (write)

30-second adjustment.

Bit 1—Reset (RESET): When 1 is written, initializes the divider circuit. This bit always reads 0.

Bit 1: RESET

Description

Runs normally.

(Initial value)

Divider circuit is reset.

Bit 0—Start Bit (START): Halts and restarts the counter (clock).

Bit 0: START

Description

Second, minute, hour, day, week, month, year counter halts.

Second, minute, hour, day, week, month, year counter runs normally.

(Initial value)

Note:

The 64-Hz counter always runs unless stopped with the RTCEN bit.

12.3

RTC Operation

12.3.1

Initial Settings of Registers after Power-On

All the registers should be set after the power is turned on.

12.3.2

Setting the Time

Part (a) in figure 12.2 shows how to set the time when the clock is stopped. This works when the

entire calendar or clock is to be set.

Part (b) in figure 12.2 describes how to set the clock when the clock is running. This works when

only part of the calendar or clock needs to be reset (e.g., changing only the seconds or only the

hour). The write status is checked using the carry flags. When there is a carry during the writing of

new data, the new data is automatically updated. Since this causes errors in the data, the data must

be rewritten if the carry flag is set to 1.

The interrupt function can be used to determine the status of the carry flag.

SH7708 데이터시트(PDF) 351 Page - Renesas Technology Corp