Microcontroller is not executing the code after powerup, After disconnecting the Status pin of the EG-25 from the MCU, code is executing normally

IoT Modules LTE Standard Module
1

Hello,

We are currently using the EG-25 module in one of our IoT products. Our system involves an MCU and EG-25 4G Module. However, we have encountered an issue where initially, the Microcontroller does not run the code and only runs after we perform an MCU reset. We are communicating with EG-25 via the UART protocol. We connected the EG-25 STATUS pin to the GPIO of the microcontroller, and a 10k pull-up resistor was added to the STATUS pin. Unfortunately, we discovered that after connecting the STATUS pin to the MCU, the code no longer runs. We were only able to successfully run the code after physically disconnecting (Track Cut) the EG25 STATUS pin from the MCU GPIO pin. The code is successfully running. We are only facing the issue after connecting the STATUS pin to the MCU.

Thanks and Regards
Karthik P R

2

hi，
Is this the schematic diagram I designed and added a pull-up 10k resistor?

3

Which MCU are you using? Some MCUs have a bootrom that automatically tries to download code over the UART interface if the MCU detects that there is a character waiting in its UART receive buffer. I recommend that you verify your MCU is not getting stuck with its bootloader waiting for data from the UART.