User's Manual

www.ti.com
Action-qualifier(AQ)Module
AQCTLA[15:0]
Action-qualifiercontrolA
EPWMA
EPWMB
TBCLK
CTR=PRD
CTR=Zero
CTR=CMPA
CTR=CMPB
CTR_dir
AQCTLB[15:0]
Action-qualifiercontrolB
AQSFRC[15:0]
Action-qualifierS/Wforce
AQCSFRC[3:0](shadow)
continuousS/Wforce
AQCSFRC[3:0](active)
continuousS/Wforce
Action-Qualifier (AQ) Submodule
The action-qualifier submodule is based on event-driven logic. It can be thought of as a programmable
cross switch with events at the input and actions at the output, all of which are software controlled via the
set of registers shown in Table 2-6 .
Figure 2-18. Action-Qualifier Submodule Inputs and Outputs
For convenience, the possible input events are summarized again in Table 2-7 .
Table 2-7. Action-Qualifier Submodule Possible Input Events
Signal Description Registers Compared
CTR = PRD Time-base counter equal to the period value TBCTR = TBPRD
CTR = Zero Time-base counter equal to zero TBCTR = 0x0000
CTR = CMPA Time-base counter equal to the counter-compare A TBCTR = CMPA
CTR = CMPB Time-base counter equal to the counter-compare B TBCTR = CMPB
Software forced event Asynchronous event initiated by software
The software forced action is a useful asynchronous event. This control is handled by registers AQSFRC
and AQCSFRC.
The action-qualifier submodule controls how the two outputs EPWMxA and EPWMxB behave when a
particular event occurs. The event inputs to the action-qualifier submodule are further qualified by the
counter direction (up or down). This allows for independent action on outputs on both the count-up and
count-down phases.
The possible actions imposed on outputs EPWMxA and EPWMxB are:
• Set High:
Set output EPWMxA or EPWMxB to a high level.
• Clear Low:
Set output EPWMxA or EPWMxB to a low level.
• Toggle:
If EPWMxA or EPWMxB is currently pulled high, then pull the output low. If EPWMxA or EPWMxB is
currently pulled low, then pull the output high.
• Do Nothing:
Keep outputs EPWMxA and EPWMxB at same level as currently set. Although the "Do Nothing" option
prevents an event from causing an action on the EPWMxA and EPWMxB outputs, this event can still
trigger interrupts and ADC start of conversion. See the Event-trigger Submodule description in
Section 2.8 for details.
38 ePWM Submodules SPRU791D – November 2004 – Revised October 2007
Submit Documentation Feedback