Reset to factory settings for HM-10

[Stève Girardin]

Hi all,

I am new on this forum and new in electronics. I am currently building a quadcopter and want to add a bluetooth module to it. I acquired a HM-10 module with a FTDI (see pictures below) and tried to set-up the baud rate with my Windows PC. I am using Arduino and/or Realterm. I mistakenly set up the rate to 1200 and now my module does not accept AT commands anymore. I understood that I have to reset to factory setting in pressing the PIO0 button. I do not find how to perform this procedure. Is it using the FTDI button, the PC or anything else?

Thanks in advance for your help!
Regards,
Stève.

 

[Harald Kapp]

According to this datasheet (page 9) there should be a pusgbutton connected to PIO0 on the module. Since the only button I can see is the one near the DTR pin, this is probably the one you should push while the module is in standby.

 

[Stève Girardin]

Hi Harald,

Thanks for your answer. There isn't actually any button on the module itself. As you saw, the only one I have is the one on the FTDI next to DTR pin. I tried to push that one without much success. By the way, how do we know that the module is in standby? I am not sure that it was the case when I tried the button on the FTDI.
I also connected the PINs as follow:
VCC - VCC
RX - TXD
TX - RXD
GND - GND
Is there any other configuration to make the FTDI button work as PIO0 button on the module?

Thanks,
Stève.

 

[Harald Kapp]

As there is no pushbutton, your module is probably of another make. I don't know the module, I only loked up the datasheet. You may try to pind the corresponding pin PIO0 on the controller chip and manually short-circuit it to ground, although I very much doubt this will help as the chip may have other firmware inside.

Have you tried different baudrates? Do you have an oscilloscope? In that case you can measure the length of the start bit when the module sends anything to the PC/arduino. From the length of the start bit you can calculate the baudrate the module uses.
Have you ever been able to establish communication with the module at all?

 

[Stève Girardin]

Hi Harald,

Thanks for your answer this was very useful. I finally sorted it out. The PiO0 was linked to the BRK pin of the module (written on the back and not visible on the picture above). I connected the BRK pin to the ground for 1'' and it made it. May module is now back to factory settings.

Many thanks!
Stève.