Section 13 Watchdog Timer (WDT)
Rev. 2.00 Mar 09, 2006 page 545 of 906
REJ09B0292-0200
13.1.4
Register Configuration
Table 13.2 summarizes the three WDT registers. They are used to select the clock, switch the
WDT mode, and control the reset signal.
Table 13.2 Register Configuration
Address
Name
Abbreviation R/W
Initial Value
Write
*
1
Read
*
2
Watchdog timer
control/status register
WTCSR
R/(W)
*
3
H'18
H'FFFFFE80
H'FFFFFE80
Watchdog timer
counter
WTCNT
R/W
H'00
H'FFFFFE80
H'FFFFFE81
Reset control/status
register
RSTCSR
R/(W)
*
3
H'1D
H'FFFFFE82
H'FFFFFE83
Notes: 1. Write by word access. It cannot be written by byte or longword access.
2. Read by byte access. The correct value cannot be read by word or longword access.
3. Only 0 can be written in bit 7 to clear the flag.
13.2
Register Descriptions
13.2.1
Watchdog Timer Counter (WTCNT)
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
WTCNT is an 8-bit read/write register. The method of writing to WTCNT differs from that of
most other registers to prevent inadvertent rewriting. See section 13.2.4, Notes on Register Access,
for details. When the timer enable bit (TME) in the watchdog timer control/status register
(WTCSR) is set to 1, the watchdog timer counter starts counting pulses of an internal clock source
selected by clock select bits 2 to 0 (CKS2 to CKS0) in WTCSR. When the value of WTCNT
overflows (changes from H'FF to H'00), a watchdog timer overflow signal (
WDTOVF
) or interval
timer interrupt (ITI) is generated, depending on the mode selected in the WT/
IT
bit in WTCSR.
WTCNT is initialized to H'00 by a reset and when the TME bit is cleared to 0. It is not initialized
in standby mode, when the clock frequency is changed, or in clock pause mode.
Содержание SH7616
Страница 10: ...Rev 2 00 Mar 09 2006 page x of xxvi ...
Страница 132: ...Section 2 CPU Rev 2 00 Mar 09 2006 page 106 of 906 REJ09B0292 0200 ...
Страница 568: ...Section 12 16 Bit Free Running Timer FRT Rev 2 00 Mar 09 2006 page 542 of 906 REJ09B0292 0200 ...
Страница 582: ...Section 13 Watchdog Timer WDT Rev 2 00 Mar 09 2006 page 556 of 906 REJ09B0292 0200 ...
Страница 662: ...Section 14 Serial Communication Interface with FIFO SCIF Rev 2 00 Mar 09 2006 page 636 of 906 REJ09B0292 0200 ...
Страница 706: ...Section 16 Serial I O SIO Rev 2 00 Mar 09 2006 page 680 of 906 REJ09B0292 0200 ...
Страница 820: ...Section 19 Pin Function Controller PFC Rev 2 00 Mar 09 2006 page 794 of 906 REJ09B0292 0200 ...
Страница 932: ...Appendix D Package Dimensions Rev 2 00 Mar 09 2006 page 906 of 906 REJ09B0292 0200 ...
Страница 935: ...SH7616 Hardware Manual ...