System Installation
96M4281o User’s Manual
3-8
How to access W83627THF CR?
In BLUEBOARD, the EFER = 002Eh, and EFDR = 002Fh.
EFER and EFDR are 2 IO ports needed to access W83627THF CR.
EFER is the Index Port, EFDR is the Data Port.
CR index number needs to be written into EFER first. Then the data will be
read/written from/to EFDR. To R/W W83627THF CR, it is needed to Enter/Enable
Configuration Mode first. When completing the programming, it is suggested to
Exit/Disable Configuration Mode.
Enter Configuration Mode: Write 87h to IO port EFER twice.
Exit Configuration Mode: Write AAh to IO port EFER.
Example
Define GPIO4 as output pin, and output “0” to this pin.
mov dx,2eh ; Enter Configuration Mode
mov al,87h
out dx,al
jmp $+2
out dx,al
mov dx,2eh
mov al,29h ; Read CR29
out dx,al
mov dx,2fh
in al,dx
and al,3Fh
or al,40h ; CR29_Bit[7..6].P[0,1]
mov ah,al
mov dx,2eh
mov al,2Ah
out dx,al
mov dx,2fh
mov al,ah
out dx,al
mov dx,2eh
mov al,07h ; Point to LDN7
out dx,al
mov dx,2fh
mov al,07h
out dx,al
mov dx,2eh ; Read CR30
mov al,30h
out dx,al
