Showing results for 
Search instead for 
Did you mean: 

STM32F205RGTx to E220-400T22D LoRa Communication Issue


Hello everyone,

I'm currently working on a project involving the STM32F205RGTx MCU and the E220-400T22D LoRa module. I'm trying to send the command "C0 04 01 09" from my STM32 to the LoRa module, but it seems that the command isn't being recognized correctly by the LoRa module.

Setup Details:

  • MCU: STM32F205RGTx
  • LoRa Module: E220-400T22D
  • Communication: UART at 9600 baud rate
  • Connections: TX on STM32 to RX on LoRa, and RX on STM32 to TX on LoRa

Issue: Despite ensuring correct physical connections and UART settings, the LoRa module does not seem to acknowledge or respond correctly to the command sent. I've tried checking and rechecking my code and connections but haven't had any luck.


  1. Has anyone faced similar issues with UART communications between STM32 and LoRa modules?
  2. Are there specific settings or configurations for the E220-400T22D that I might be overlooking?
  3. Any suggestions on troubleshooting steps would be greatly appreciated.

Thanks in advance for your time and help!


I think you miss the point, this stuff isn't sent as ASCII characters with spaces


uint8_t data[] = { 0xC0,0x040,0x01,0x09 };

HAL_UART_Transmit(huart, data, sizeof(data), 500);

Tips, Buy me a coffee, or three.. PayPal Venmo
Up vote any posts that you find helpful, it shows what's working..

Firstly, thank you very much for taking the time to respond to my query and for your suggestion regarding the byte-oriented data transmission. I followed your advice and adjusted my code to send the command "C0 04 01 09" as a byte array directly:

uint8_t buff_send[] = {0xC0, 0x04, 0x01, 0x09};
HAL_UART_Transmit(&huart2, buff_send, sizeof(buff_send), 1000);

Unfortunately, I'm still facing issues with the LoRa module not recognizing the command. Here's what I've done following your suggestion:

  1. Verified UART Configuration: Checked that the baud rate and other settings are aligned on both the STM32 and the LoRa module.
  2. Checked Physical Connections: Ensured that the TX and RX connections are correct and secure.
  3. Used Debugging Tools: I employed a logic analyzer to monitor the data being transmitted. The data appears correct at the transmission point.