This is simple serial passthrough program to enable communication between PC (USB) and BLE (Serial2). When uploading this program to arduino be sure to choose Arduino/Genuino Zero (Native USB Board).
IMPORTANT! -- In order for this program to work the MCU has to be setup as described in Bootloader & Setup readme of wearable-sensor-hardware repo.
BLE module used in wearable sensor is RN4870. Firmware inside RN4870 provides the control interface based on ASCII commands sent over UART. In wearable sensor MCU and RN4870 are connected through Serial2 UART.
The ASCII commands can control functions such as connection setup, accessing Generic Attribute Profile (GATT) characteristics, changing configuration settings, and reading status. The UART can operate in Command mode, to receive ASCII commands, or Data mode to exchange data using “Transparent UART” Bluetooth service.
For wearable sensor the most basic use of module will be following;
- initialize Serial2 to be able to send commands to module
- configure module so that BLE hub (RPI3 or smartphone) can discover and connect to the module
- configure other necessary parameters
- once connection is established, use module in Transparent UART mode
Necessary commands to setup proper operation of module as described above can be found in RN4870 User Guide. Table below summarizes the most basic commands.
| Command | Description |
|---|---|
| $$$ | Enters command mode, responded by CMD> |
| + | Turn local echo on |
| S-,test | Sets the module name to 'test' |
| SF,1 | This command resets the configurations into factory default |
| SN,XX | This command sets the device name to “XX” |
| SR,8000 | the device enables hardware flow control. |
| SR,0100 | the device uses Write without Response for Transparent UART |
| SS,80 | This command sets the device information service |
| SS,40 | This command sets the transparent UART service |
| &,MAC | Generates and assigns a 6-byte random address to the local device. |
| A | Start advertising |
| Y | Stop advertising |
| K,1 | Command K is used to disconnect the active BTLE link. |
| R,1 | Reboot device |
| D | Used to display critical information of module over UART. |
| SW,pin,function | Used to configure pin function. |
Feel free to test these commands (and other from User Guide) from your PC using serial passthrough Arduino program from this repo.