BLE HM11 usage question (Digikey Part #1597-1359-nd)

Anyone have any experience with the HM-11 module? I have an HM-11 connected to a PIC microcontroller as follows:

VCC ----> 3.3V
GND ----> GND
TX (HM11) ----> RX (PIC)
RX (HM11) ----> TX (PIC)

When I write data to the HM11 using the “BLE Scanner” app on my smartphone, the PIC receives the data just fine over RS-232 (configured @ 115200 8-N-1) which seems to confirm serial communication is working properly. But if I transmit an “AT” command from my PIC (which I can see on the microcontroller’s TX pin using a scope) with no line end characters, the HM11 module does not send back an “OK” as expected. Anyone have an ideas for what might be wrong? Thanks!


Hello @Ashok , I have not used the HM-11 module but you may want to try changing the PIC baud rate to 9600. Seeed’s documentation shows 9600 as default baud rate.