UART-B Connection Issues on Colibri IMX7D with Evaluation Board v3.2B

Hello Toradex Community,

I am working with the Colibri Evaluation Board v3.2B, equipped with a Colibri IMX7D 1GB System on Module. My goal is to run Debian OS on the ARM Cortex-A7 processor and an RTOS on the ARM Cortex-M4. I am following the setup instructions provided at Toradex Developer: FreeRTOS on the Cortex-M4 of a Colibri iMX7, but I’m encountering issues when trying to connect to the UART_B for the Cortex-M4 processor debug console.

Here’s my current setup:

  1. UART-A Connection: I’m using a USB-B to USB-A cable connected from port X27 on the Colibri Evaluation Board to my MacBook. All jumpers are set as described in the Configuring Serial Port Debug Console documentation. I can successfully connect to the Cortex-A7 processor’s serial port using screen /dev/tty.usbserial-A10MWGNJ 115200. Note: this path is slightly different from the one mentioned in the UART on Linux documentation.
  2. UART-B Connection: I have connected the RS-232 Top on X25 on the Colibri Evaluation Board using the Null Modem Cable (RS232), which then connects to a DB9-Male to USB-A cable from the Carrier Board Accessory Kit v1.1c. This cable is plugged into my laptop. However, I am unable to detect the USB device when running ls /dev/tty*.

I am wondering if there might be an issue related to the jumper configuration for JP19, JP20, JP17, and JP21 that is affecting UART-B connectivity.

Additionally, I would like to confirm if the DB9-Male to USB-A cable provided in the accessory kit is indeed capable of supporting data transfer when used with the Null Modem RS-232 cable?

Any guidance or suggestions to resolve these connectivity issues would be greatly appreciated. Thank you in advance for your support!

Hello Toradex Community,

I wanted to follow up on my previous query regarding the issues I was facing with the UART-B connectivity on the Colibri Evaluation Board v3.2B. After some troubleshooting and testing different configurations, I’ve successfully resolved the problem and would like to share the solution with the community.

Resolution: The RS-232 cable included in the Carrier Board Accessory Kit v1.1c is a Null Modem (Cross-Over) cable, not a Straight-Through cable as initially assumed. Switching to a Straight-Through DB( cable enabled successful connectivity to the Cortex-M4 processor’s debug console via UART-B.

For anyone experiencing similar issues, ensure that you are not using a Null Modem RS-232 cable for UART-B connections. This confirmation may prevent connectivity issues and facilitate proper setup.

This issue can be marked as closed.