!!!! I Don't Writen FreeRTOS and BS818A-2 Yet !!!!
I hope use it and enjoy.
I use Stm32f0k6 and Keil Compiler and Stm32CubeMX wizard.
Please Do This ...
1) Select "General peripheral Initalizion as a pair of '.c/.h' file per peripheral" on project settings.
2) Select 1 pin as gpio output for Clock and 1 pin as gpio input for Data.
3) Config your Bs81x_Conf.h.
4) After Bs81x_Init() you can call Bs81x_Scan(). return -1 if no key pressed.