VIA Technologies ARTiGO A820, Быстрый старт

Страница: 15 / 28

ARTiGO A820 Linux BSP v3.2.1 Quick Start Guide
11
5.1.2. Setting Up RS-485 Mode
To set up and test the RS-485 communication over the COM 1 port, set the COM mode
switch to the RS-485 position as shown below.
COM mode switch diagram
Enable the RS-485 on the ARTiGO A820 system with the following command:
$ imx_rs485 1
Connect the host machine to the ARTiGO A820 COM 1 port with an RS-485 cable. To
start the Minicom serial communication program on the ARTiGO A820, use the
following command:
$ minicom -s
Connect to the /dev/ttymxc0 serial device with the following settings:
+--------------------------------------------------------------+
| A - Serial Device : /dev/ttymxc0 |
| B - Lockfile Location : /var/lock |
| C - Callin Program : |
| D - Callout Program : |
| E - Bps/Par/Bits : 115200 8N1 |
| F - Hardware Flow Control : No |
| G - Software Flow Control : No |
+--------------------------------------------------------------+
Serial port setting of RS-485 mode
Start a serial communication program on the host machine with the same
communication settings using the appropriate serial device. Afterwards the host machine
and the ARTiGO A820 will be able to communicate through the programs (for example
sending a keypress on one machine should be shown on the other machine).
Please note that the software setting for the RS-485 communication is not preserved
over reboot. The “imx_rs485” command needs to be run whenever the machine is
restarted to set up the COM 1 port correctly for RS-485 communication.
To switch the COM 1 port back to RS-232 communication mode from RS-485, adjust the
COM mode select switch and use the following command:
$ imx_rs485 0
COM 1 DIO
USB
RESET
PWR
WIRELESS
485 232
232 485