FlexIo Simulates UART

NXP2 — Mon, 29 Jun 2026 01:26:08 GMT

Hello,
Currently, there are the following issues with the S32K118 chip from your company:

(1) Using FlexIO to simulate UART with the SDK version (S32SDK_S32K1XX_RTM_4.0.1) allows for loopback testing, and the official demo is also an example of loopback. However, when using the MCAL version (SW32K1_S32M24x_RTD_R21-11_3.0.0) of FlexIO to simulate UART, it was found that loopback testing could not be performed. Is it because the MCAL version does not support it?

(2) Considering that the MCAL version does not support it, if the SDK version of FlexIO is used to simulate UART for mass production projects, are there any safety concerns?
Best Wishes,

NXP2.

Re: FlexIo Simulates UART

VaneB — Mon, 29 Jun 2026 22:53:24 GMT

Hi @NXP2

I am not sure if I understood your question correctly, but please note that FlexIO itself does not provide a dedicated internal loopback feature. In the SDK example, the loopback test is achieved by connecting the FlexIO TX and RX signals externally using a wire.

Regarding S32SDK_S32K1XX_RTM_4.0.1, please note that this is a relatively old software release and is no longer being actively maintained. We generally recommend using SW32K1_S32M24x_RTD_R21-11_3.0.0, as it is the latest software release for the S32K1 family and continues to receive maintenance updates, bug fixes, and new features.

Also, could you provide a bit more information about the intended application? That would help to better understand your use case.

BR, VaneB

topic Re: FlexIo Simulates UART in S32K

FlexIo Simulates UART

Re: FlexIo Simulates UART