MCX Microcontrollersのトピック回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE_MASK))?

Elakiya — Thu, 05 Mar 2026 07:29:58 GMT

Hi, I am new with NXP, I am trying to test LPUART protocol in the MCUXpresso IDE with our MCXN546VKL PCB with UART PIO8 and PIO9 pins to IoT module, before that I try to test the TX and RX function for the UART polling and DMA. In simple loopback UART test with polling mode, when I try to send sample data through uart TX it stuck at "while (0U == (base->STAT & LPUART_STAT_TDRE_MASK))" in fsl_lpuart.c file. I given 12MHz for FLEXCOMM4 and 150MHz for system clock, why this is happening, I have attached .png file of configuration screenshot also with this post please check and give clear details. Thank you

回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

Harry_Zhang — Fri, 06 Mar 2026 07:59:23 GMT

Hi @Elakiya

On MCXN devices, the TDRE bit only becomes 1 when the UART module is actually clocked and the TX FIFO level is less than or equal to the configured TX watermark.

May I ask if you have enabled the FlexComm clock?

I think you can refer to the mcxn547 sdk lpuart demo.

Harry

回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

Elakiya — Mon, 09 Mar 2026 06:13:41 GMT

Hello @Harry_Zhang, I have MCXN546VKL PCB board, but as per your instruction I have used example file of LPUART polling from the SDK of MCXN547V for same pin PIO8 and PIO9 of uart pins and manually changed in GlobalInfo of the processor and package_id to MCXN456VKL inside the clock_config.c and pin_mux.c.

processor: MCXN546

package_id: MCXN546VKL

And build the project, without any error it is transmitting and receiving the UART polling operation fine, but still I get a error notification inside the pin configuration setting. I have shared the screenshot of the notification and error issue shown in Problem Tool: MCUconfiguration.

How can I quick fix the error, by changing the processor setting also from MCXN547 to MCXN546 in configuration to remove the error notification from the configuration page. Please check my screenshot and update the solution. Thanks in advance.

回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

Elakiya — Tue, 24 Mar 2026 06:27:02 GMT

Hello @Harry_Zhang, Kindly give me update and solution above issue, I need to run my in project in startup_mcxn546_cm33_core0.c instead of running in startup_mcxn547_cm33_core0.c. If I create in manually, I am getting clock config issue in uart and MCU. I have changed my processor and clock manually to mcxn546 from mcxn547, but I could not make changes in startup file and also processor error warning inside my chip configuration page. Or please provide my simple project in mcxn546 configuartion with freeRTOS in UART polling & DMA operation test code. Kindly give me update for the above issue. Thank you.

回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

Harry_Zhang — Tue, 24 Mar 2026 07:50:36 GMT

Hi @Elakiya

Sorry for the late reply, have you tried creating a freertos project based on the mcxn946 SDK package?

Harry

回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

Elakiya — Tue, 24 Mar 2026 08:53:35 GMT

Hi @Harry_Zhang , I have not created it in mcxn546 or mcxn946, but I tried to run basic uart operation first in mcxn546, it was not working and making clock issue in uart and mcu. So I created mcxn547 example uart polling project from sdk and changed its processor and package id manually in pin_mux.c and clock_config.c to build and make it for mcxn546 mcu. It is sending and receiving the uart data in my mcxn546 board. But it is running in startup_mcxn547_cm33_core0.c and showing in pin configuration page of .mex file given below.

I need to run it in startup_mcxn546_cm33_core0.c and clear this error in config. I have attached my project with this post, please check it.

Issue: Processor "MCXN547" detected in the MCUXpresso_IDE project does not match the currently selected "MCXN546".

Level: Error

回复： In UART protocol test MCXN546VKL, it stuck at while (0U == (base->STAT & LPUART_STAT_TDRE

Harry_Zhang — Tue, 24 Mar 2026 10:15:56 GMT

Hi @Elakiya

I checked your early post.

"manually changed in GlobalInfo of the processor and package_id to MCXN456VKL inside the clock_config.c and pin_mux.c.

processor: MCXN546

package_id: MCXN546VKL"

This method is incorrect, so it will report an error. We currently have no way to prevent this error.

First, MCXN546 and MCXN547 are mostly the same, with only differences in the number of GPIOs and flash RAM size.

Based on your above messages. I have two suggestions.

1. If you create a project based on your MCXN546 SDK, you just need to modify some files base on the mcxn5xxevk_lpuart_polling and you can use the config tool directly.

2. If you want to use mcxn5xxevk_lpuart_polling as the base, you cannot directly use the config tool tool. But you can create another mcxn546 project, configure the pins and clocks you need with the config tool, and then copy the generated code to project mcxn5xxevk_lpuart_polling.

Harry