SH7751 Datasheet, PDF (379/1224 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

10. Clock Oscillation Circuits
10.7.2 Register Configuration
The WDT has the two registers summarized in table 10.5. These registers control clock selection
and timer mode switching.
Table 10.5 WDT Registers
Name
Initial
Area 7
Abbreviation R/W Value P4 Address Address
Access Size
Watchdog timer
counter
WTCNT
R/W* H'00 H'FFC00008 H'1FC00008 R: 8, W: 16*
Watchdog timer
control/status
register
WTCSR
R/W* H'00 H'FFC0000C H'1FC0000C R: 8, W: 16*
Note: * Use word-size access when writing. Perform the write with the upper byte set to H'5A or
H'A5, respectively. Byte- and longword-size writes cannot be used.
Use byte access when reading.
10.8 WDT Register Descriptions
10.8.1 Watchdog Timer Counter (WTCNT)
The watchdog timer counter (WTCNT) is an 8-bit readable/writable counter that counts up on the
selected clock. When WTCNT overflows, a reset is generated in watchdog timer mode, or an
interrupt in interval timer mode. WTCNT is initialized to H'00 only by a power-on reset via the
RESET pin.
To write to the WTCNT counter, use a word-size access with the upper byte set to H'5A. To read
WTCNT, use a byte-size access.
Bit:
7
6
5
4
3
2
1
0
Initial value:
0
0
0
0
0
0
0
0
R/W: R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Rev.4.00 Oct. 10, 2008 Page 281 of 1122
REJ09B0370-0400