Kontron MSM-LP Manual User Guide V106 - Manual (Page 32)

MSM-LP / Special Features
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Example: Disable Watchdog
; Watchdog device activation
mov dx, 4Eh
; Store port in dx for in/out instruction
mov al, 77h ; Configuration mode value
out dx, al ; Output 2 times to enter config mode
out dx, al ;
mov al, 07h ; Device number register
out dx, al ; Move value to IND register
inc dx ; Increment dx to DAT register = 0x4F
mov al, 08h ; Device number 8 - watchdog
out dx, al ; Set DAT register
dec dx ; Decrement dx to IND register
mov al, 0F1h ; WDT_CNT register
out dx, al ; Move value to IND register
inc dx ; Increment dx to DAT register 0x4F address
mov al, 0 ; Set Timer to 10 second interval
out dx, al ; Set DAT register 2 times to disable watchdog
out dx, al ;
dec dx ; Decrement dx to IND register
mov al, 30h ; Activation register address = 0x30
out dx, al ; Move value to IND register
inc dx ; Increment dx to DAT register
mov al, 0h ; Deactivation value WDT_EN = 0
out dx, al ; Set DAT register – enable watchdog device
dec dx ; Decrement dx to IND register to 0x4E address
mov al, 0AAh ; Leave configuration mode
out dx, al ; Move value to IND register
In C language:
outportb(0x4E,0x77); //output 2 times to enter configuration mode
outportb(0x4E,0x77);
outportb(0x4E,0x7);
//device index
outportb(0x4F,0x8); //device number 8
outportb(0x4E,0xF1); //WDT_CNT register
outportb(0x4F,0); // Set Timer to 0, 2 times
outportb(0x4F,0); //
outportb(0x4E,0x30); //activation register
outportb(0x4F,0x00); //deactivate watchdog WDT_EN = 0
outportb(0x4E,0xAA); //Leave configuration mode