FabiaTech FB2631, Руководство пользователя

Страница: 71 / 89

FabiaTech Corporation
65
¾
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 in the same.)
Step 2: Disable TXC (transmitter control), the bit 0 of the address of 4
just sets “0”.
NOTE: Control the FB2631 CPU card’s DTR signal to the RS-485
＇
s TXC communication.
¾
Send out one character (Transmit)
Step 1: Enable TXC signal, and the bit 0 of the address of 4 just sets “1”.
Step 2: Send out the data. (Write this character to the 0 of the current
COM port address)
Step 3: Wait for the buffer’s data empty. Check transmitter holding register
(THRE, bit 5 of the address of 5), and transmitter shift register
(TSRE, bit 6 of the address of 5) are all sets must be “0”.
Step 4: Disabled TXC signal, and the bit 0 of the address of 4 sets “0”
¾
Send out one block data (Transmit – the data more than two characters)
Step 1: Enable TXC signal, and the bit 0 of the address of 4 just sets “1”.
Step 2: Send out the data. (Write all data to the 0 of the current COM
port address)
Step 3: Wait for the buffer’s data empty. Check transmitter holding register
(THRE, bit 5 of the address of 5), and transmitter shift register
(TSRE, bit 6 of the address of 5) are all sets must be “0”.
Step 4: Disabled TXC signal, and the bit 0 of the address of 4 sets “0”