1.2.2 WEX – for the 16-Bit TCE

The WEX provides extra functions to the timer/counter in Waveform Generation (WG) modes. It is intended primarily for use in different types of motor control and other power control applications. The WEX consists of five independent and successive units.

The Dead-Time Insertion (DTI) unit generates OFF time where the non-inverted low side (LS) and inverted high side (HS) of the Waveform Output (WO) are low. This OFF time is called dead time, and the Dead-Time Insertion unit ensures that the LS and HS never switch simultaneously.

All channels have a mutual register that controls the dead time. The high and low sides have independent dead-time settings, and the dead-time registers are double-buffered.

In Pattern Generation mode (PGM), the Dead-Time buffers are unavailable. The dead-time can still be implemented using only the data registers, as when PGM is enabled only on some outputs, and Complementary PWM with dead-time is needed on other outputs.

Four half-bridge channels are required to drive a bipolar stepper motor. Each half-bridge channel is controlled with two PWM signals in counter-time, alternated and inverted.

The following figure depicts the TCE and WEX working together.

For application examples, check the link below:

onlinedocs.microchip.com/oxy/GUID-8FB8D192-E8C9-4748-B991-D4D842E01591-en-US-1/index.html