Nexcom Peak 555A User Manual page 87

Peak 555A User's Guide
Port Used
Default at F2
Bit definitions of F2
D4: 1 select NMI
0 select Reset
D3: 1 Enable watch dog timer
0 Disable watch dog timer
< D2, D1, D0>: 111 :
110 :
101 :
100 :
011 :
010 :
001 :
000 :
Watch dog Timer Programming Procedure
• Power on or reset the system
The values of D4~D0 in port F2 are zero, i.e. the watch dog timer is disabled
• Clear the WDT, repeatedly read port F2 with the duration no longer than the
preset
time out interval, otherwise, the WDT will generate NMI or reset the system.
Watch Dog Timer
N/A
Select 1 second
Select 2 second
Select 4 second
Select 8 second
Select 16 second
Select 32 second
Select 64 second
A-2