WDT Programmimg Guide A-7
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Step 2 .
MOV DX,3F0H
MOV AL,2CH
OUT DX,AL
MOV DX,3F1H
IN AL,DX
; READ CR2C
OR AL,08H
AND AL,0FBH
MOV AH,AL
MOV DX,3F0H
MOV AL,2CH
OUT DX,AL
MOV DX,3F1H
MOV AL,AH
OUT DX,AL
; CR2C-b[3,2]P[1,0]
MOV DX,3F0H
MOV AL,07H
OUT DX,AL
; point to Logical Device Number Register
MOV DX,3F1H
MOV AL,08H
OUT DX,AL
; select logical device 8
;
MOV DX,3F0H
MOV AL,0F2H
OUT DX,AL
MOV DX,3F1H
MOV AL,02H
OUT DX,AL
; LD8-CRF2-P02h