Rev. 2.00, 09/03, page 286 of 690
Figures 10.1 shows a block diagram of the WDT.
WTCSR
Standby
control
Bus interface
WTCNT
Divider
Clock selector
Clock
Standby
mode
Peripheral
clock
Standby
cancellation
Reset
control
Clock selection
WDT
Overflow
Internal
reset
request
Interrupt
control
Interrupt
request
WTCSR:
WTCNT:
Legend
Watchdog timer control/status register
Watchdog timer counter
Figure 10.1 Block Diagram of WDT
10.2
Register Descriptions
The WDT has the following two registers. Refer to section 24, List of Registers for the details of
the addresses of these registers and the state of registers in each operating mode.
•
Watchdog timer counter (WTCNT)
•
Watchdog timer control/status register (WTCSR)
10.2.1
Watchdog Timer Counter (WTCNT)
The watchdog timer counter (WTCNT) is an 8-bit readable/writable register that increments on the
selected clock. When an overflow occurs, it generates a reset in watchdog timer mode and an
interrupt in interval timer mode. The WTCNT counter is not initialized by an internal reset due to
the WDT overflow. The WTCNT counter is initialized to H'00 only by a power-on reset using the
RESETP pin.
Use a word access to write to the WTCNT counter, with H'5A in the upper byte. Use a byte access
to read WTCNT.
Summary of Contents for SH7705
Page 2: ......
Page 70: ...Rev 2 00 09 03 page 24 of 690 ...
Page 194: ...Rev 2 00 09 03 page 148 of 690 ...
Page 284: ...Rev 2 00 09 03 page 238 of 690 ...
Page 338: ...Rev 2 00 09 03 page 292 of 690 ...
Page 354: ...Rev 2 00 09 03 page 308 of 690 ...
Page 374: ...Rev 2 00 09 03 page 328 of 690 ...
Page 420: ...Rev 2 00 09 03 page 374 of 690 ...
Page 476: ...Rev 2 00 09 03 page 430 of 690 ...
Page 482: ...Rev 2 00 09 03 page 436 of 690 ...
Page 552: ...Rev 2 00 09 03 page 506 of 690 ...
Page 630: ...Rev 2 00 09 03 page 584 of 690 ...
Page 739: ...SH7705 Group Hardware Manual REJ09B0082 0200O ...