205
Block Diagram: Figure 9.18 shows a block diagram of the watchdog timer.
ø
Internal data bus
PSS
TCSRW
TCSRW
ø/8192
Internal reset
signal
Legend:
TCSRW: Timer control/status register W
TCW:
Timer counter W
PSS:
Prescaler S
Figure 9.18 Block Diagram of Watchdog Timer
Register Configuration: Table 9.17 shows the watchdog timer register configuration.
Table 9.17
Watchdog Timer Registers
Name
Abbrev.
R/W
Initial Value
Address
Timer control/status register W
TCSRW
R/W
H'AA
H'FFB4
Timer counter W
TCW
R/W
H'00
H'FFB5
9.6.2
Register Descriptions
Timer Control/Status Register W (TCSRW)
Bit
7
6
5
4
3
2
1
0
B6WI
TCWE
B4WI
TCSRWE
B2WI
WDON
BOWI
WRST
Initial value
1
0
1
0
1
0
1
0
Read/Write
R
R/(W)
*
R
R/(W)
*
R
R/(W)
*
R
R/(W)
*
Note:
*
Can be written to only when the write condition is satisfied. For the write conditions, see the
individual bit descriptions.