HD6412240 RENESAS [Renesas Technology Corp], HD6412240 Datasheet - Page 436

• Manufacturer Part Number: HD6412240
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family / H8S/2200 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 11 Watchdog Timer
11.2.4
The watchdog timer's TCNT, TCSR, and RSTCSR registers differ from other registers in being
more difficult to write to. The procedures for writing to and reading these registers are given
below.
Writing to TCNT and TCSR
These registers must be written to by a word transfer instruction. They cannot be written to with
byte instructions.
Figure 11.2 shows the format of data written to TCNT and TCSR. TCNT and TCSR both have the
same write address. For a write to TCNT, the upper byte of the written word must contain H'5A
and the lower byte must contain the write data. For a write to TCSR, the upper byte of the written
word must contain H'A5 and the lower byte must contain the write data. This transfers the write
data from the lower byte to TCNT or TCSR (see figure 11.2).
Rev.3.00 Mar. 26, 2007 Page 394 of 772
REJ09B0355-0300
TCNT write
TCSR write
Notes on Register Access
Address: H'FFBC
Address: H'FFBC
Figure 11.2 Format of Data Written to TCNT and TCSR
15
15
H'5A
H'A5
8 7
8 7
Write data
Write data
0
0