w83977eg Winbond Electronics Corp America, w83977eg Datasheet - Page 84

• Manufacturer Part Number: w83977eg
• Description: Winbond Isa I/o W83977ef W83977eg
• Manufacturer: Winbond Electronics Corp America

10.2.2 Configurate the configuration registers
The chip selects the logical device and activates the desired logical devices through Extended
Function Index Register(EFIR) and Extended Function Data Register(EFDR). EFIR is located at the
same address as EFER, and EFDR is located at address (EFIR+1).
First, write the Logical Device Number (i.e.,0x07) to the EFIR and then write the number of the desired
logical device to the EFDR. If accessing the Chip(Global) Control Registers, this step is not required.
Secondly, write the address of the desired configuration register within the logical device to the EFIR
and then write (or read) the desired configuration register through EFDR.
10.2.3 Exit the extended function mode
To exit the extended function mode, one write of 0xAA to EFER is required. Once the chip exits the
extended function mode, it is in the normal running mode and is ready to enter the configuration mode.
10.2.4 Software programming example
The following example is written in Intel 8086 assembly language. It assumes that the EFER is located
at 3F0h, so EFIR is located at 3F0h and EFDR is located at 3F1h. If HEFRAS (CR26 bit 6) is set,
3F0h can be directly replaced by 370h and 3F1h replaced by 371h.
;-----------------------------------------------------------------------------------
; Enter the extended function mode ,interruptible double-write
;-----------------------------------------------------------------------------------
MOV
MOV
OUT
OUT
;-----------------------------------------------------------------------------
; Configurate logical device 1, configuration register CRF0 |
;-----------------------------------------------------------------------------
MOV
MOV
OUT
MOV
MOV
OUT
;
MOV
MOV
OUT
MOV
MOV
OUT
;------------------------------------------
; Exit extended function mode
;------------------------------------------
MOV
MOV
OUT
DX,3F0H
AL,87H
DX,AL
DX,AL
DX,3F0H
AL,07H
DX,AL
DX,3F1H
AL,01H
DX,AL
DX,3F0H
AL,F0H
DX,AL
DX,3F1H
AL,3CH
DX,AL
DX,3F0H
AL,AAH
DX,AL
; point to Logical Device Number Reg.
; select logical device 1
; select CRF0
; update CRF0 with value 3CH
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W83977EF-AW/W83977EG-AW
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