topic Re: The MM9Z1J638BM2EP cannot download programs and debug in Sensors

The MM9Z1J638BM2EP cannot download programs and debug

shiweili — Tue, 03 Feb 2026 21:48:12 GMT

Hi NXP Team,

Our products use the MM9Z1J638BM2EP chip. During the sample debugging and testing phase, many products failed to download the program. The specific information is as follows:

When using Micro P&E to download the program, the error content is displayed as shown in the following figure,
The total number of samples is 70, and the number of samples that cannot download programs is 30.
After power-on, there is always a periodic low level signal on the chip reset pin, as shown in the figure below,

Above, please help to analyze and give some suggestions.

Thanks a lot

Re: The MM9Z1J638BM2EP cannot download programs and debug

TomasVaverka — Tue, 15 Nov 2022 10:50:31 GMT

Hi Shiwei,

The possible reasons for reset signal at RESET_A pin are shown in Figure 41:

The analog die contains window watchdog WWD active after reset (states POR->RESET->Normal mode).

There is default tWDTO = b100 = 256ms interval after reset where WWD must be disabled or initialized.

I guess, that loading your code into MCU at your board may take more time than 256ms and watchdog at analog die restarts MCU => During programming ONLY - disconnect the RESET <> RESET_A line.

I hope it helps.

Best regards,

Tomas