AXIOMTEK AX10445 Series, Руководство пользователя

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AX10445 Module Series User
’
s Manual
Application
22
those for COM1 and COM2.
When you are using the AX10445 Series in transferring text
files, you only need to use 7 data bits because the letters or
any punctuation mark won
’
t require the 8th bit. By sending
only 7 bits, you slightly increase the speed of sending file.
But in transferring a program file you have to transmit all 8
bits, because the EOF mark cannot be used to signal the end
of the file. This is the reason why a count of the number of
bytes to be transferred must be sent to the receiver prior to
sending the file.
4.2 Demo Program for QB4.5
‘ TITLE : Demo program for QB4.5 at RS485 mode, two wire operation
‘
‘ JOB : Data sent by COM1 port, data received by COM2 port
‘
‘PROGRAM:
CLS
‘ open two communication ports
OPEN “com1:9600,n,8,1” FOR RANDOM AS #1 LEN = 256
OPEN “com2:9600,n,8,1” FOR RANDOM AS #2 LEN = 256
‘ turn off RTS
OUT &H3FC, 8
OUT &H2FC, 8
‘ main loop
DO
‘ send a string from com1
‘ turn on RTS and DTR
OUT &H3FC, 11
‘ write data to device
PRINT #1, “This is a string sent out through com1.”
‘ wait for complete
SLEEP 1
‘ turn off RTS and DTR
OUT &H3FC, 8
‘ check data received from com2
IF NOT EOF(2) THEN