Formosa Industrial Computing MBM-530NS, Руководство пользователя

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MBM-530NS User’s Manual -99-
6. PROGRAMMING RS-485
The majority of the communicative operations of the RS-485 are the same as
the RS-232. When the RS-485 proceeds with transmission, which needs control
the TXC signal (RS-232 and RS-485 control the signal differently), the installation
steps are as follows:
Step 1:
Enable TXC
Step 2:
Send out data
Step 3:
Waiting for data empty
Step 4:
Disable TXC
Note:
Please refer to the “Serial Port” section in the chapter “System Controller” for
the detailed description of the COM port’s register.
(1) Initialize COM port
Step 1:
Initialize COM port in the receiver interrupt mode, and /or
transmitter interrupt mode. (All of the communication protocol
buses of the RS-485 are the same.)
Step 2:
Disable TXC (transmitter control), the bit 0 of the address of
4 just sets at “0”.
NOTE:
This is to control the MBM-530NS CPU card’s DTR signal to
the RS-485’s TXC communication.