Apalis Imx8- Console image - Serial port issue

link textHi Team,

We are using Apalis imx8 module with Eaglet base board.

We have built Yocto console embedded Linux image with core 3.0 by following the below link. We have attached the major commands for reference.

We are testing serial port RS232 communication in with current image. Serial port 3(/dev/ttyLP0) and 4(/dev/ttyLP2) are working properly. We have used minicom inbuilt tool to test serial port.
Port 3 Tx with Port 4 Rx,
Port 3 Rx with Port 4 Tx.
We have observed below issues in serial port 1 and 2,

Self-loopback test Issue:

Port 1 Tx with Port 1 Rx,
Port 2 Tx with Port 2 Rx.

We have tested serial port 1 (/dev/ttyLP1) with self-loopback and noticed sending characters were properly received back in the same windows. But if we send “Enter” key then we have faced issue. We are getting garbage values on this case. Next if we send character, it is properly received. We have attached the screenshot for reference.

Could you please check the issue and update us?
Note: Self loopback serial data properly received in serial port 2 (/dev/ttyLP3)

Port loopback:

Port 1 Tx with Port 2 Rx,
Port 1 Rx with Port 2 Tx.

We have sent data from serial port 1 (/dev/ttyLP1) and data received properly in serial port 2(/dev/ttyLP3). But if we send data(characters) from serial port 2(ttyLP3) to serial port 1(ttyLP1) first data always reflected back to the same window. Next data received in serial port 1. This issue occurs for remaining data transfer.

In some cases, if we send “enter” key to receiving, then it is hanged and transmission stopped. We have to close minicom to send next data. Could you please check the issue and provide your inputs?

Our final requirement is to support RS485 mode with baud rate 115200. Initially, we are validating RS232 serial communication.

Mohanraj K.

Have you disabled HW flow control?