[AUDIO LOGO]

Hi, and welcome to the continuation in the C2000 enhanced pulse-width modulator, or ePWM, video series. I'm Peter Long. In this video, I'll be giving an overview of the trip zone submodule found within the ePWM module.

The trip zone submodule is helpful in the event of fault conditions, allowing you to pull the ePWM signal to a desired state. There are two types of trips, a one-shot trip and a cycle-by-cycle trip. So I'll go into greater detail about these two types of trips.

On the right is the time-based submodule block diagram. The part in blue represents the cycle-by-cycle trip. This cycle-by-cycle trip is used in current-limiting operations. Whenever the CBC trip is detected, the ePWM output is temporarily driven to a certain state, and the output will return to its original state when the trip is released-- in other words, when the trip reaches a certain state like 0, period, or 0 and period event.

So you notice that there's some extra circuitry at the top of the cycle-by-cycle block which enables the ePWM output to return to its original state. The part in green is the circuitry for the one-shot trip. This one-shot trip is used in major short circuit or over-current conditions.

When a one-shot trip is detected, the ePWM outputs are driven to the specified state, but the difference here is that the outputs will remain in that trip state until the trip is manually cleared. And that's really the fundamental difference between these two trips. Again, the one-shot will cause the output to remain tripped until the one-shot trip is cleared, whereas with the cycle-by-cycle trip the ePWM output has the ability to return to its original state the next time a certain event occurs within the ePWM cycle.

Now, for this example, suppose I'm interested in configuring a GPIO to cause a cycle-by-cycle trip, which drives my ePWM and outputs low. Using the input crossbar, any GPIO can be routed as a trip signal into the ePWM module. For this example, suppose I choose GPIO 25 to be the trip source. That GPIO will be routed through the input crossbar into the ePWM module using input 1.

To realize that GPIO as the trip source, we need to choose trip 1 as a CBC source, since that corresponds to where GPIO 25 is routed in the input crossbar. Now, since we're doing a cycle-by-cycle trip, we have to choose at what event the trip will be cleared. For this one, I'm choosing a 0 event.

The next part is choosing the specified output whenever that trip does occur. This can be done by programming TZA and TZB to clear when the trip occurs. And those are just two bits in the TZCTL trip zone control register.

Doing this within SysConfig, first we need to configure a GPIO for GPIO 25. This GPIO will be an input that's fed into the ePWM module. Then we have to set up the input crossbar-- in this instance, input crossbar 1-- to map to that GPIO 25.

Once we have that set up, we can configure ePWM trip zone. So really the only thing that needs to be configured here are the TZA and TZB events, specifically pulling them to a low voltage state. Next, the CBC source should be selected as TZ1 cycle-by-cycle. I need to configure the latch clear signal, so that will be when the counter equals 0. Overall, you can see that SysConfig makes it easy to configure the submodule within the ePWM module.

That concludes the trip zone submodule overview for the ePWM module on C2000 devices. Watch the other videos within this peripheral video series to learn more about the enhanced functionalities provided in the ePWM module. C2000 Academy is also a helpful resource for building understanding of C2000 devices.

In addition, read through our available ePWM application reports to see advanced applications of the ePWM module, which you too can leverage in your next application.