r5s77631ay266bgv Renesas Electronics Corporation., r5s77631ay266bgv Datasheet - Page 845

Manufacturer Part Number

r5s77631ay266bgv

Renesas 32-bit Risc Microcomputer Superhtm Risc Engine Family Sh-4a Series

Manufacturer

Renesas Electronics Corporation.

Figure 22.3 shows examples of the time reading procedures.

If a carry occurs while the time is being read, the correct time will not be obtained and the read

must be repeated. The procedure for reading the time without using interrupts is shown in figure

22.3 (a), and the procedure using carry interrupts in figure 22.3 (b). The method without using

interrupts is normally used to keep the program simple.

Time Reading Procedures

(a) Reading time without using interrupts

Figure 22.3 Examples of Time Reading Procedures

(b) Reading time using interrupts

Disable carry interrupts

Enable carry interrupts

Read counter register

Interrupt generated?

Clear carry flag

Carry flag = 1?

Clear RCR1.CIE to 0.

Clear RCR1.CF to 0

(Write 1 to RCR1.AF so that alarm flag

is not cleared).

Read RCR1 register and check CF bit.

Set RCR1.CIE to 1.

Clear RCR1.CF to 0

(Write 1 to RCR1.AF so that alarm flag

is not cleared).

Clear RCR1.CIE to 0.

Rev. 1.00 Oct. 01, 2007 Page 779 of 1956

Section 22 Realtime Clock (RTC)

REJ09B0256-0100