Section 11 Watchdog Timer (WDT)
Rev. 5.00 May 29, 2006 page 316 of 698
REJ09B0146-0500
11.2
Register Description
The WDT has two registers that select the clock, switch the timer mode, and perform other
functions. Refer to section 23, List of Registers, for more details of the addresses and access sizes.
•
Watchdog timer counter (WTCNT)
•
Watchdog timer control/status register (WTCSR)
11.2.1
Watchdog Timer Counter (WTCNT)
The watchdog timer counter (WTCNT) is an 8-bit read/write register that increments on the
selected clock. When an overflow occurs, it generates a reset in watchdog timer mode and an
interrupt in interval time mode. The WTCNT is initialized to H'00 only by a power-on reset
through the
RESETP
pin. Use a word access to write to the WTCNT, with H'5A in the upper byte.
Use a byte access to read WTCNT.
Bit
Bit Name
Initial Value
R/W
Description
7 to 0
All 0
R/W
8-bit counter
Note:
The watchdog timer counter (WTCNT) is more difficult to write to than other registers to
prevent from the erroneous writing to the register. Refer to section 11.2.3 Notes on Register
Access.
11.2.2
Watchdog Timer Control/Status Register (WTCSR)
The watchdog timer control/status register (WTCSR) is an 8-bit read/write register composed of
bits to select the clock used for the count, bits to select the timer mode, and overflow flags. The
WTCSR is initialized to H'00 only by a power-on reset through the
RESETP
pin. When a WDT
overflow causes an internal reset, the WTCSR retains its value. When used to count the clock
settling time for canceling a software standby, it retains its value after counter overflow. Use a
word access to write to the WTCSR, with H'A5 in the upper byte. Use a byte access to read
WTCSR.
Summary of Contents for SH7706 Series
Page 8: ...Rev 5 00 May 29 2006 page viii of xlviii ...
Page 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Page 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Page 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Page 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Page 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Page 749: ...SH7706 Group Hardware Manual ...