h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 456

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 12 Watchdog Timer
Writing to RSTCSR: RSTCSR must be written to by word transfer instruction to address
H'FF76. It cannot be written to with byte instructions.
Figure 12.3 shows the format of data written to RSTCSR. The method of writing 0 to the WOVF
bit differs from that for writing to the RSTE bits.
To write 0 to the WOVF bit, the write data must have H'A5 in the upper byte and H'00 in the
lower byte. This clears the WOVF bit to 0, but has no effect on the RSTE bits. To write to the
RSTE bit, the upper byte must contain H'5A and the lower byte must contain the write data. This
writes the values in bit 6 of the lower byte into the RSTE bit, but has no effect on the WOVF bit.
Reading TCNT, TCSR, and RSTCSR: These registers are read in the same way as other
registers. The read addresses are H'FF74 for TCSR, H'FF75 for TCNT, and H'FF77 for RSTCSR.
Rev. 5.00 Sep 22, 2005 page 430 of 1136
REJ09B0257-0500
Writing 0 to WOVF bit
Writing to RSTE bit
Address: H'FF76
Address: H'FF76
Figure 12.3 Format of Data Written to RSTCSR (WDT0)
15
15
H'A5
H'5A
8 7
8 7
Write data
H'00
0
0