Difference between revisions of "Transclusion: IOT-GATE-iMX8: RS485 / RS232"
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** Select "Serial port setup" | ** Select "Serial port setup" | ||
** Press the letter 'f'. | ** Press the letter 'f'. | ||
+ | ** Press the letter 'h'. | ||
+ | ** Press the letter 'i'. | ||
** Press the Esc key twice. | ** Press the Esc key twice. | ||
* The characters that are typed in the terminal are transmitted to the RS485 port. | * The characters that are typed in the terminal are transmitted to the RS485 port. | ||
* The characters that are received from the RS485 port are displayed in the terminal. | * The characters that are received from the RS485 port are displayed in the terminal. | ||
* Press CTRL-a followed by the letter 'x' to exit from Minicom | * Press CTRL-a followed by the letter 'x' to exit from Minicom |
Revision as of 06:14, 25 July 2022
IOT-GATE-iMX8 / SBC-IOT-iMX8 features a RS485 / RS232 port. Only half-duplex mode is supported for the RS485.
The RS485 / RS232 interface is routed to rear panel terminal block connector see drawing.
RS485 / RS232 connector pin-out:
Pin Number | RS485 Functionality | RS232 Functionality |
1 | NEG A/- | TXD |
2 | NEG B/+ | RTS |
3 | Ground | Ground |
4 | NC | CTS |
5 | NC | RXD |
6 | Ground | Ground |
Contents
RS485 / RS232 Mode Selection
The UART mode is stored in the U-Boot environment.
U-Boot environmnet commands are used to set/get the UART mode.
Set RS485 mode
root@iot-gate-imx8:~# cl_setenv uart_mode rs485 root@iot-gate-imx8:~# reboot
Set RS232 mode
root@iot-gate-imx8:~# cl_setenv uart_mode rs232 root@iot-gate-imx8:~# reboot
Get UART mode
root@iot-gate-imx8:~# fw_printenv uart_mode
Example
Serial terminal emulator application can be used to test the RS485 port.
- Use the following command to start Minicom with the user space device of the RS485 (/dev/ttymxc0).
root@iot-gate-imx8:~# minicom -D /dev/ttymxc0
- Follow the following steps to disable hardware flow control
- Open the menu "Configure Minicom" with CTRL-a followed by the letter 'o'.
- Select "Serial port setup"
- Press the letter 'f'.
- Press the letter 'h'.
- Press the letter 'i'.
- Press the Esc key twice.
- The characters that are typed in the terminal are transmitted to the RS485 port.
- The characters that are received from the RS485 port are displayed in the terminal.
- Press CTRL-a followed by the letter 'x' to exit from Minicom