fix unknown variable error; fix conversion of uS to bit value, and add limits.
fix unknown variable error; fix conversion of uS to bit value, and add limits.

peteflorence/crazyflie-tools,blandry/crazyflie-tools,blandry/crazyflie-tools,blandry/crazyflie-tools,peteflorence/crazyflie-tools,peteflorence/crazyflie-tools,peteflorence/crazyflie-tools,blandry/crazyflie-tools