Systick clock frequency changed to 250Hz
uac command "getpwm" now returns the Motor pwm instead of the remote control pwm signals
functions for uart dma data transfer added
tigger flag for main loop execution added; this flag is set in the systick interrupt and is reset in the main loop
main loop is only being executed if the tigger flag is set; the trigger flag is set by the systick interrupt which is fired at a rate of 250Hz