Specifications

Compare Units
6-38
The time base for the compare units and the associated PWM circuits is pro-
vided by GP timer 1 (for EVA) or GP timer 2 (for EVB), which can be in any of
its counting modes when the compare operation is enabled. Transitions occur
on the compare outputs.
Compare Inputs/Outputs
The inputs to a compare unit include:
- Control signals from control registers
- GP timer 1/3 (T1CNT/T3CNT) and its underflow and period match signals
- RESET
The output of a compare unit is a compare match signal. If the compare opera-
tion is enabled, this match signal sets the interrupt flag and causes transitions
on the two output pins associated with the compare unit.
Compare Operation Modes
The operation mode of the compare units is determined by the bits in COM-
CONx. These bits determine:
- Whether the compare operation is enabled
- Whether the compare outputs are enabled
- The condition on which the compare registers are updated with the values
in their shadow registers
- Whether space vector PWM mode is enabled
Operation
The following paragraph describes the operation of the EVA compare unit. The
operation of the EVB compare unit is identical. For EVB, GP timer 3 and
ACTRB are used.
The value of the GP timer 1 counter is continuously compared with that of the
compare register. When a match is made, a transition appears on the two out-
puts of the compare unit according to the bits in the action control register (AC-
TRA). The bits in ACTRA can individually specify each output to be toggle ac-
tive high or toggle active low (if not forced high or low) on a compare match.
The compare interrupt flag associated with a compare unit is set when a
compare match is made between GP timer 1 and the compare register of this