HL 7802 CTS stays high and no AT-response


We are trying to send AT-commands to HL7802-module from a STM32F4-chip. The commands are being sent correctly from the stm32 side, but the HL7082 never responds.

The CTS-line seems to go high when powering the device on and it stays there permanently, so it seems that the module never reaches AT-Ready status. Our connection can be seen in the picture.

The crossed out resistors and mosfets were originally connected, but have been removed in order to try to make the module work (it still doesn’t).

What could be done to get the device into AT-Ready status?


try to using with Unmanaged POWER_ON_N per 4.6.1 on PTS.
also, why you are connect the DTR to DSR? its not required, manly if you are in sleep mode.