Jason2382 
I have done some research on NDK. Can it really directly translate the c file to be a driver in the kernel layer??? In fact, I am doing a project to make a robot using Tiny210. I need to use the I2C, GPIO and PWM output of the core board. I need to write the driver for I2C, GPIO and PWM . Should I use NDK to compile the driver or I need to access the linux kernel ??? I still don't know how to access the GPIO ???? Any one can give me some idea or keywords ???