Enhanced PWM (ePWM) Module
Table 15-37. Possible Actions On a Trip Event
TZCTL[TZA]
EPWMxA
and/or
and/or
TZCTL[TZB]
EPWMxB
Comment
0
High-Impedance
Tripped
1h
Force to High State
Tripped
2h
Force to Low State
Tripped
3h
No Change
Do Nothing. No change is made to the output.
Example 15-2. Trip-Zone Configurations
Scenario A:
A one-shot trip event on TZ1 pulls both EPWM1A, EPWM1B low and also forces EPWM2A and EPWM2B
high.
•
Configure the ePWM1 registers as follows:
–
TZSEL[OSHT1] = 1: enables TZ as a one-shot event source for ePWM1
–
TZCTL[TZA] = 2: EPWM1A will be forced low on a trip event.
–
TZCTL[TZB] = 2: EPWM1B will be forced low on a trip event.
•
Configure the ePWM2 registers as follows:
–
TZSEL[OSHT1] = 1: enables TZ as a one-shot event source for ePWM2
–
TZCTL[TZA] = 1: EPWM2A will be forced high on a trip event.
–
TZCTL[TZB] = 1: EPWM2B will be forced high on a trip event.
Scenario B:
A cycle-by-cycle event on TZ5 pulls both EPWM1A, EPWM1B low.
A one-shot event on TZ1 or TZ6 puts EPWM2A into a high impedance state.
•
Configure the ePWM1 registers as follows:
–
TZSEL[CBC5] = 1: enables TZ5 as a one-shot event source for ePWM1
–
TZCTL[TZA] = 2: EPWM1A will be forced low on a trip event.
–
TZCTL[TZB] = 2: EPWM1B will be forced low on a trip event.
•
Configure the ePWM2 registers as follows:
–
TZSEL[OSHT1] = 1: enables TZ1 as a one-shot event source for ePWM2
–
TZSEL[OSHT6] = 1: enables TZ6 as a one-shot event source for ePWM1
–
TZCTL[TZA] = 0: EPWM1A will be put into a high-impedance state on a trip event.
–
TZCTL[TZB] = 3: EPWM1B will ignore the trip event.
15.2.2.8.4 Generating Trip Event Interrupts
and
illustrate the trip-zone submodule control and interrupt logic, respectively.
1544
Pulse-Width Modulation Subsystem (PWMSS)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated