RS232/485 Port
There is a simple serial port that supports both the RS232 and RS485 modes. The port operates through two signal terminals. In the RS232 mode, these are RX and TX; in the RS485 mode they are RX/TX+ and RX/TX–. There is no provision for flow control (RTS and CTS lines are not present), or the RS422 interface.
The serial port can be used, for instance, to connect to another IB100x board. In the RS232 mode, the serial port can also be used to update the firmware of the EM1000 module located on the NB10x0 network board.
Serial Port Lines
The serial port lines are on terminal block 1:
|
Terminal # |
Function |
|
9 |
Sensors 3 and 4, positive line (+) |
|
8 |
Sensor 4, negative line (–) |
|
7 |
Sensor 3, negative line (–) |
|
6 |
Sensors 1 and 2, positive line (+) |
|
5 |
Sensor 2, negative line (–) |
|
4 |
Sensor 1, negative line (–) |
|
3 |
Serial port: RX (RS232); TX/RX– (RS485) |
|
2 |
Serial port: TX (RS232); TX/RX+ (RS485) |
|
1 |
System (common) ground |
Serial Port Control
Four lines of the EM1000 module located on the NB10x0 network board control the serial port.
|
Line |
Function |
Corresponding EM1000 I/O line |
IC1000 cable line |
|
RX (input) |
Receive line of the serial port |
GPIO8/RX0 |
17 |
|
TX (output) |
Transmit line of the serial port |
GPIO9/TX0 |
19 |
|
MODE (output) |
Mode selection:
|
GPIO44 |
14 |
|
DIR (output) |
Direction control in RS485 mode:
|
GPIO0/RTS0 |
1 |
*GPIO line configured as input (default state)
Do not forget to configure the TX, MODE, and DIR lines as outputs. A pull-down resistor on the MODE line ensures that the system boots up with the RS232 port selected.