Aaeon PFM-535S Manual de usuario descargar pdf (Pagina 36)

PC/104 CPU Module PFM-535S

Appendix A Programming the Watchdog Timer A-3

Here are steps to setup watchdog timer:

1. Set Bit 6 = 0 to disable the timer.

2. Write the desired counter value to 3Bh, 3Ah, 39h.

3. Set Bit 6 = 1 to enable the timer, the counter will begin to count

up.

4. When counter reaches the setting value, the time out will

generate signal setting by index 38h bit[7:4]

5. BIOS can read index 3Ch Bit 7 to decide whether the Watchdog

timeout event will happen or not.

To clear the watchdog timer counter:

1. Set Bit 6 = 0 to disable timer. This will also clear counter at the

same time.

WDT1

WDT1 does not use index and data port to access WDT registers. It

uses I/O port 68H~6DH. The time resolution of WDT1 is 30.5 u

second. Here are registers information:

1 2 ... 31 32 33 34 35 36 37 38 39 40 41 ... 52 53

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Aaeon PFM-535S Manual de usuario Pagina 36