EZ80F91MCU Datasheet, PDF (145/396 Pages) Zilog, Inc. – eZ80Acclaim-TM Flash Microcontrollers

eZ80F91 MCU
Product Specification
126
Watch-Dog Timer Reset Register
The Watch-Dog Timer Reset register, detailed in Table 49, is an 8-bit Write Only
register. The Watch-Dog Timer is reset when an A5h value followed by a 5Ah value
is written to this register. Any amount of time can occur between the writing of the
A5h value and the 5Ah value, so long as the WDT time-out does not occur prior to
completion. Any value other than 5Ah written to the Watch-Dog Timer Reset regis-
ter after the A5h value requires that the sequence of Writes (A5h,5Ah) be restarted
for the timer to be reset.
Table 49. Watch-Dog Timer Reset Register
(WDT_RR = 0094h)
Bit
7
6
5
4
3
2
1
0
Reset
X
X
X
X
X
X
X
X
CPU Access
W
W
W
W
W
W
W
W
Note: X = Undefined; W = Write Only.
Bit
Position
[7:0]
WDT_RR
Value Description
A5h The first Write value required to reset the WDT prior to a time-
out.
5Ah The second Write value required to reset the WDT prior to a
time-out. If an A5h,5Ah sequence is written to WDT_RR, the
WDT timer is reset to its initial count value, and counting
resumes.
PS019209-0504
PRELIMINARY
Watch-Dog Timer