Hello everyone,
I'm currently trying to send and receive SMS with the "Adafruit FONA GSM SIM800H" module and a Nucleo-L432KC board. Initially, I tested the module with an Arduino UNO as described in the Adafruit FONA documentation, and everything worked fine—I was able to send and receive SMS messages. However, now I want to use the STM32 board.
I created a new project using STM32CubeMX and configured HUART1 for the GSM module and HUART2 for serial print. The issue I'm facing is: when I send "AT\r\n" with HAL_UART_Transmit, my rx_buffer remains empty. I initially thought it could be a logic level issue, as the Arduino UNO operates at 5V and the STM32 board uses 3.3V, but even after adding a logic level converter, there is still no response to the AT command.
I have connected the module’s RX to D5 and TX to D4, and I've enabled interrupts for D4.
Does anyone have any ideas on what could be causing this issue or suggestions on what I could try?
