Sensoray 417 Manual de usuario descargar pdf (Pagina 13)

Instruction Manual 12

80x86 Assembly Language Drivers

;***********************************************************

; Handshake a command byte into the 417 command register.

; Entry:DX points to 417 base port address.

; AL contains command byte to send to 417.

;***********************************************************

;INITIALIZE DRIVER

XMIT: PUSH AX ; Save command byte to be sent to 417

INC DX ; Set address pointer to status port

;WAIT FOR “COMMAND REGISTER EMPTY”

XLOOP: IN AL,DX ; Read status port

TEST AL,80H ; and test CRMT status flag

JE XLOOP ; Loop until command register is empty

;SEND COMMAND BYTE TO 417 BOARD

DEC DX ; Set address pointer to command register

POP AX ; Restore command byte

OUT DX,AL ; and write it into command register

RET ;EXIT DRIVER

;***********************************************************

; Handshake a byte from the 417 data register.

; Entry:DX points to 417 base port address.

; Exit:AL contains data byte read from 417.

;***********************************************************

;INITIALIZE DRIVER

RCV: INC DX ; Set address pointer to status port

;WAIT FOR “DATA AVAILABLE”

RLOOP: IN AL,DX ; Read 417 status port

TEST AL,40H ; and test DAV status flag

JE RLOOP ; Loop until data register is full

;READ DATA BYTE FROM 417 BOARD

DEC DX ; Set address pointer to 417 data register

IN AL,DX ; Read byte from data register

RET ;EXIT DRIVER

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Sensoray 417 Manual de usuario Pagina 13