Section 14 Watchdog Timer
14.2
Register Descriptions
The watchdog timer has the following registers.
•
•
•
Timer control/status register WD (TCSRWD)
Timer counter WD (TCWD)
Timer mode register WD (TMWD)
14.2.1
Timer Control/Status Register WD (TCSRWD)
TCSRWD performs the TCSRWD and TCWD write control. TCSRWD also controls the
watchdog timer operation and indicates the operating state. TCSRWD must be rewritten by using
the MOV instruction. The bit manipulation instruction cannot be used to change the setting value.
Initial
Bit
Bit Name Value
R/W
Description
7
B6WI
1
R/W
Bit 6 Write Inhibit
The TCWE bit can be written only when the write value of
the B6WI bit is 0.
This bit is always read as 1.
6
TCWE
0
R/W
Timer Counter WD Write Enable
TCWD can be written when the TCWE bit is set to 1.
When writing data to this bit, the value for bit 7 must be 0.
Bit 4 Write Inhibit
5
4
B4WI
1
0
R/W
R/W
The TCSRWE bit can be written only when the write
value of the B4WI bit is 0. This bit is always read as 1.
TCSRWE
Timer Control/Status Register WD Write Enable
The WDON and WRST bits can be written when the
TCSRWE bit is set to 1.
When writing data to this bit, the value for bit 5 must be 0.
Bit 2 Write Inhibit
3
B2WI
1
R/W
This bit can be written to the WDON bit only when the
write value of the B2WI bit is 0.
This bit is always read as 1.
Rev. 3.00 Sep. 10, 2007 Page 276 of 528
REJ09B0216-0300
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