Installations
•
21
2.5 Watchdog Timer Configuration
The function of the watchdog timer is to reset the system automatically. It
contains a one-second/minute resolution down counter, CRF6 of logical
device 8, and two Watchdog control registers, CRF5 and CRF7 of logical
device 8. We can uses compatible PNP protocol to access configuration
registers for setting up watchdog timer configuration.
To program configuration registers, the following configuration sequence
must be followed:
Enter the extended function mode by writing 87h to the location 2Eh twice.
Configure the configuration registers
Exit the extended function mode by writing 0AAh to the location 2Eh.
The following example is written in Intel 8086 assembly language. It will
reset the system in 15 seconds. We can use both keyboard interrupt and
mouse interrupt to cause the watchdog to reload and start to count down
from the value of CRF6.
.model small
.code
.startup
begin:
;-------------------------------------------------------------------
; Enter the extend function mode, interrupt double-write
;-------------------------------------------------------------------
mov dx,2eh
mov al,87h
out dx,al
out dx,al
mov dx,2eh
mov al,2bh
;CR2B, bit4-> 0 = WDTO
; bit4-> 1 = GP24
out dx,al
mov dx,2fh
mov al,0c0h
out dx,al
mov dx,2eh
mov al,07h
out dx,al
mov dx,2fh
mov al,08h
;device 8
out dx,al
Summary of Contents for NuPRO-775 Series
Page 1: ...NuPRO 775 Series Half Size Socket 370 Pure PCI Industrial SBC User s Guide Recycled Paper ...
Page 2: ......
Page 6: ......
Page 14: ...8 Introduction Figure 1 Layout of key components ...
Page 15: ...Introduction 9 Figure 2 NuPRO 775 Mechanical Drawing ...
Page 19: ...Installations 13 Figure 3 Connector location on the NuPRO 775 ...
