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FRDM-KW41Z BLE for HM-10 pairing and transmission

Question asked by Javier Monreal Trigo on May 31, 2018
Latest reply on Jun 9, 2018 by Javier Monreal Trigo

Good morning,


It is my first time programming Bluetooth in a uC without AT commands, and I'm having troubles in transmitting messages between the demo example provided in the SDK and my PC.


I am using an FRDM-KW41Z board and an HM-10, both connected to my PC through USB and terminal. Both have the terminals opened in my PC properly (because I did it in previous experiences the same way, see Additional information).

I set the HM-10 as master, and the FRDM as a slave (SW4 button) and bound them (both have fixed red LED shinning), now what I write in the HM-10 terminal should be shown in the FRDM terminal, but it doesn't show anything.

Both UARTs are set to 115200 bauds, 8 bits, NP.


I am developing a Matlab GUI for remotely controlling the FRDM, that is why I am using the HM-10 as BLE master.


What can I do for receiving and sending messages from FRDM-KW41Z to HM-10 and vice-versa? Or what am I doing wrong? Every reply will be really helpful, I don't know what is missing. 


Thanks in advance,




-> EDIT (3rd June): I think the problem is the GATT profiles: HM-10 has a non-standard profile for communication, meanwhile the KW41Z has another. I can connect to the HM-10 with my smartphone and transmit, but I'm not sure what I shall modify in my NXP project to modify the GATT to make it compatible with HM-10 one.


Software information:

I'm using MCUxpresso IDE v10.1.1_606 (JLink and OpenSDA seem installed). The demo example I am using is from SDK_2.x_FRDM-KW41Z (version 2.2.0), called frdmkw41z_wireless_examples_bluetooth_wireless_uart_freertos.


Additional information:

I had no problem in using GPIO, DAC and ADC. Neither using the beacon demo.

HM-10 is working properly, I paired two of them and communicated via terminals.

I can connect the FRDM running the demo example with my smartphone, and use the PC-terminal and the Android app-terminal.