353
TCSRW—Timer control/status register W
H'B4
Watchdog timer
Bit
Initial value
Read/Write
7
B6WI
1
R
6
TCWE
0
R/(W)
*
5
B4WI
1
R
4
TCSRWE
0
R/(W)
*
3
B2WI
1
R
0
WRST
0
R/(W)
*
2
WDON
0
R/(W)
*
1
B0WI
1
R
Watchdog timer reset
1
0
[Clearing conditions]
• Reset by RES pin
• When 0 is written to WRST
while writing 0 to B0WI
when TCSRWE is set to 1
1
[Setting condition]
When TCW overflows and
an internal reset signal is
generated
Bit 0 write disable
1
0
Writing to bit 0 enabled
1
Writing to bit 0 disabled
Watchdog timer on
1
0
Watchdog timer operation disabled
1
Watchdog timer operation enabled
Bit 2 write disable
1
0
Writing to bit 2 enabled
1
Writing to bit 2 disabled
Timer control/status register W write enable
1
0
Writing to bit 2 and bit 0 disabled
1
Writing to bit 2 and bit 0 enabled
Bit 4 write disable
1
0
Writing to bit 4 enabled
1
Writing to bit 4 disabled
Timer counter W write enable
1
0
Data writing to TCW disabled
1
Data writing to TCW enabled
Bit 6 write disable
1
0
Writing to bit 6 enabled
1
Writing to bit 6 disabled
Note:
*
Writing possible only when write condition is satisfied