Intel 8XC196MC, 8XC196MD, 8XC196MH manual Waveform Generator Operation, Timebase Generator

8XC196MC, MD, MH USER’S MANUAL

Table 9-2. Waveform Generator Control and Status Registers (Continued)

Mnemonic	Address	Description
WG_CONTROL	1FCCH	Waveform Generator Control
		The control register determines the waveform generator’s operating mode,
		starts and stops the counter, specifies the dead time for all phases, and
		indicates the current count direction.
WG_COUNTER	1FCAH	Waveform Generator Count Value
		The read-only counter register reflects the current counter value.
WG_OUTPUT	1FC0H	Waveform Generator Output Control
		The output control register configures the waveform generator’s outputs and
		selects their active polarity.
WG_PROTECT	1FCEH	Waveform Generator Protection
		The protection register enables and disables the protection circuitry and the
		outputs, selects level-sensitive or edge-triggered interrupts, and controls
		which value of the edge or level will trigger an interrupt request.
		8XC196MH only: This register also selects the method for disabling the
		outputs: inactive states or weak pull-ups.
WG_RELOAD	1FC8H	Waveform Generator Reload Value
		The reload register contains a value that is compared with the counter value.
		The actions performed based on this comparison depend on the operating
		mode.

9.3WAVEFORM GENERATOR OPERATION

This section describes the major components of the waveform generator: the timebase generator, the phase driver channels, and the control and protection circuitry. It also explains how the buff- ered registers are updated and describes the similarities and differences between the center- aligned and edge-aligned operating modes. Finally, it describes the two types of interrupt requests that the waveform generator can generate and explains how to enable the interrupts.

9.3.1Timebase Generator

The timebase generator establishes the carrier period of the PWM outputs. You specify this period by writing a value to the reload register (WG_RELOAD). This value is loaded into the counter register (WG_COUNTER) when the system is initialized and periodically (depending on the op- erating mode) thereafter. You can read the counter register to determine the current counter value and you can write to the reload register to change the reload value at any time.

The 16-bit timebase counter is clocked every state time. The control register (WG_CONTROL) enables and disables the counter, controls the counting mode, and reflects the count direction. When the counter is enabled, it continuously counts between 0001H and the reload value. Writing 0000H to the reload register or clearing the enable bit in the control register stops the counter.

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