Contec bx200 SERIES, User Manual

Page: 45 / 115

4. Each Component Function
38
BX-2x0-DCxxxx, BX-2x0D-DCxxxx User’s manual
;-------------------------------------------
CHK_CMD:
MOV
DX,2A4H
IN AL,DX
TEST AL,2 ;Check status of output
JNZ CHK_CMD
MOV DX,2A0H
MOV AL,93H ;Set 485 Command
OUT DX,AL
CHK_DATA:
MOV
DX,2A4H
IN AL,DX
TEST AL, 2 ;Check status of output
JZ CHK_DATA
MOV DX,2A0H
MOV AL, 0 ;Bit0: 0 Receiver Disable, 1 Receiver Enable
;Bit1: 0 Transmitter Disable, 1 Transmitter Enable
CHK_STA:
MOV
DX,2A4H
IN AL,DX
TEST AL,1 ;Check status of input
JZ CHK_STA
MOV DX,2A0H
IN AL,DX ;Command success if AL = 93H
;-------------------------------------------
;Close
;-------------------------------------------
CHK_CLOSE1:
MOV
DX,2A4H
IN AL,DX
TEST AL,2 ;Check status of output
JNZ CHK_CLOSE1
MOV DX,2A0H
MOV AL,AAH ;Close Command
OUT DX,AL
CHK_CLOSE2:
MOV
DX,2A4H
IN AL,DX
TEST AL,1 ;Check status of input
JZ CHK_CLOSE2
MOV DX,02A0H
IN AL,DX ;Close success if AL = 55H