Installation
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27
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, CRF2 of logical
device 8, and two Watchdog control registers, WDT_CTRL0 and
WDT_CTRL1 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:
1.
Enter the extended function mode by writing 87h to the location 3F0h
twice.
2.
Configure the configuration registers.
3.
Exit the extended function mode by writing 0AAh to the location
3F0h.
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 CRF2.
MODEL SMALL
DATA
CODE
STARTUP
BEGIN:
-----------------------------------------------------------------------
Enter the extended function mode, interruptible double-write
-----------------------------------------------------------------------
MOV
DX,3F0H
MOV
AL,87H
OUT
DX,AL
OUT
DX,AL
----------------------------------------------------------------------
Configurate logical device 7, configuration register CRE2
----------------------------------------------------------------------
MOV
DX,3F0H
MOV
AL,07H
OUT
DX,AL ;point to logical Device Number Reg.
MOV
DX,3F1H
MOV
AL,07H ;select device 7
Summary of Contents for NuPRO-590 Series
Page 2: ......
Page 6: ......
Page 8: ......
Page 16: ...8 Introduction Figure 1 Layout of key components ...
Page 17: ...Introduction 9 Board Dimensions Figure 2 NuPRO 590 Mechanical Drawing ...
Page 20: ...12 Installation Figure3 Jumper Locations on the NuPRO 590 ...
