Unable to issue any AT commands to BT BLE Breakout Board

Question

I'm a programmer, more from the software side but I do have hardware working knowledge too. I've completed the Arduino Starter Kit's 15 projects, Now trying to build some things with ESP8266 and HM-10 BLE.

I was able to connect ESP8266 to my network and start a TCP server too via AT commands(using Arduino's Serial Monitor and FTDI 232RL USB to TTL converter)

I also have a HM-10 Bluetooth Breakout+connector board (Its based on CC2541 by TI (visible on the SMD chip)) brought from here.

Using the same setup I was able to issue AT commands successfully for ESP8266. However I tried many things, different baud rates and \r\n combinations; I just couldnt get the HM-10 to acknowledge my AT commands.

Setup: link

Connections:

Arduino +5V --> +ve input of LDO regulator --> 3.3v OUPUT to Vcc of HM-10
Common GND for LDO regulator input and output pins, FTDI 232RL and HM10

FTDI TX --> voltage divider (1k ohms --> connection output to HM 10 RX --> 1k ohms --> 1k ohms --> GND)

There is no code/sketch as of now. I'm just trying to hook up the HM-10 BLE chip. I can pair my Android phone to it but that's not the concern here.

The concern here is I cannot configure the HM-10 using AT commands.

The HM-10 does not reply an "OK" acknowledge for my "AT" command. Nothing happens in the serial monitor after hitting enter. Just a blank screen.

Is there a way by which I can determine what baud rate to use and what combination of \r and \n?

What am I missing here?

Answer 1

I found out that there is no need for a voltage divider to reduce the voltage being given to RX pin of BLE from FTDI's TX since both FTDI232RL and HM-10 are 3.3V devices (from here)

I connected the TX from FTDI directly to the RX of BLE using female to female jumpers.

Used No Line Ending and 9600 as the baud rate.

Then it worked fine, I got an OK acknowledge for my AT command.