ADLINK Technology NuPRO-590 Series User Manual

ADLINK Technology NuPRO-590 Series User Manual Manual pdf 35 page image

Installation • 272.5 Watchdog Timer ConfigurationThe function of the watchdog timer is to reset the system automatically. Itcontains a one-second/minute resolution down counter, CRF2 of logicaldevice 8, and two Watchdog control registers, WDT_CTRL0 andWDT_CTRL1 of logical device 8. We can uses compatible PNP protocol toaccess configuration registers for setting up watchdog timer configuration.To program configuration registers, the following configuration sequencemust be followed:1. Enter the extended function mode by writing 87h to the location 3F0htwice.2. Configure the configuration registers.3. Exit the extended function mode by writing 0AAh to the location3F0h.The following example is written in Intel 8086 assembly language. It will resetthe system in 15 seconds. We can use both keyboard interrupt and mouseinterrupt to cause the watchdog to reload and start to count down from thevalue of CRF2.MODEL SMALLDATACODESTARTUPBEGIN:-----------------------------------------------------------------------Enter the extended function mode, interruptible double-write-----------------------------------------------------------------------MOV DX,3F0HMOV AL,87HOUT DX,ALOUT DX,AL----------------------------------------------------------------------Configurate logical device 7, configuration register CRE2----------------------------------------------------------------------MOV DX,3F0HMOV AL,07HOUT DX,AL ;point to logical Device Number Reg.MOV DX,3F1HMOV AL,07H ;select device 7