at7601fg AME, Inc., at7601fg Datasheet - Page 24

• Manufacturer Part Number: at7601fg
• Description: Printer Port Controller
• Manufacturer: AME, Inc.

6. Configuration Register
24
AT7601F
The configuration registers of AT7601F are implemented to provide special function control, such as power-down
mode, I/O port tri-state control, and select address-decoding modes. The current IRQ and DMA channel used for
The configuration registers can only be accessed through configuration I/O ports (INDEX and DATA) under configura-
tion mode. These two ports'addresses are assigned to high base address+04H and high base address+05H.
To enter configuration mode, the configuration Key (78H) must be write twice into INDEX register successively. And
write AAH into INDEX register to exit configuration mode.
An example program for entering configuration mode, accessing configuration register, and exiting
configuration mode as shown following:
; **************************************
; * ENTER CONFIG MODE
; * Low base address: 378H
; * And address mode 0 is selected *
; * A10 is connected to A10
;***************************************
MOV DX,77CH
MOV AL,78H
OUT
OUT
;************************************
; * Accessing Config Register *
;*************************************
MOV DX,77CH
MOV AL ,F0H ; Accessing CR-F0
OUT DX,AL
INC DX
MOV AL,3FH
OUT DX,AL ; Write 3FH to CR-F0
IN AL,DX ; Read CR-F0
;******************************
;* Exit Config Mode
;*******************************
DEC DX
MOV AL,AAH
OUT DX,AL
INT 21
AT7601F can be setting in configuration registers.
DX,AL
DX,AL
AME, Inc.
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Printer Port Cotroller
Rev. B.02