Board – CJMCU The CJMCU is a tiny (80mm) board running a STM32F103, which contains a 3-Axis Compass (HMC5883L) and an Accelerometer/Gyro (MPU6050). This board does not have an onboard USB-Serial converter, so an external adapter is needed. Hardware revisions Revision Notes 1 No boot jumper pads by LED1. Uses blue and red LEDs 2