The design of the Capture / Compare Unit (CCU) of the C504 microcontroller allowsgeneration of 7 digital output signals without CPU load. A set of Special FunctionRegisters (SFR, see corresponding tables in C504 User’s Manual) offers to the usersextreme flexibility to choose of possible waveforms, such as pulse width modulation(PWM). By appropriate setting of SFRs, frequency (period register), duty cycles (compareregisters) and active / passive levels (COINI register) of output signals can be easilycontrolled.These features should be used with respect to the application, e.g. motor control usingthree phase transistor inverters with automatic dead time generation by the CCU. Thedead time is implemented with a 16-bit offset register. In order to generate correct outputpulse patterns for three phase transistor inverters, passive levels for highside switchesmust be inverted compared to those of lowside switches.