TMS320F28377S: ePWMxA and ePWMxB are controlled by different TZ

Jordan Zhou

Genius 10120 points

Part Number: TMS320F28377S

Hi,

There's a request about ePWMxA and ePWMxB in one ePWM module, like ePWM1

We'd like to use TZ1 to "one shot" ePWM1A, and TZ2 to "one shot" ePWM1B. TZ2 is about 2~2.5us delayed to TZ1.

Is that possible?

Br, Jordan

over 6 years ago

0 Nima Eskandari over 6 years ago

TI__Guru 52040 points

Let me do a quick look in the docs and I’ll get back to you.

0 Nima Eskandari over 6 years ago in reply to Nima Eskandari

TI__Guru 52040 points

Yes this is possible. However you cannot just use the Trip-Zone submodule. You will need to use the Digital Compare Submodule. You can use the TZ1 for Trip-Zone submodule and use it qualifiers to change EPWMxA and TZ2 for Digital Compare to control EPWMxB.

Nima Eskandari

0 Jordan Zhou over 6 years ago in reply to Nima Eskandari

TI__Genius 10120 points

Hi, Nima
Yes, we are thinking to use DC to control ePWMxA and ePWMxB independently.
ONE DC event is not enough, TWO should be used. Is that right?
Br, Jordan

0 Nima Eskandari over 6 years ago in reply to Jordan Zhou

TI__Guru 52040 points

That is correct you can use both DC events to accomplish your task.

Nima Eskandari

0 Jordan Zhou over 6 years ago in reply to Nima Eskandari

TI__Genius 10120 points

Nima,
Yes, two DC events can accomplish ePWMxA and ePWMxB' one shot function.
Is it possible to accomplish both "one shot" and "CBC"?

Actually, customer's request on ePWM1A and ePWM1B are:
1) They are inverted;
2) They both are controlled by "one shot" and "CBC", like TZ1 for ePWM1A and ePWM1B "one shot", while TZ2 for their CBC;
3) During "one shot" or "CBC", ePWM1A is always shut down first, 2~2.5us (no later ePWM1B is shut down;
In this case, it's not possible to use two events to accomplish.
Do you have any other suggestion?
We are thinking to do in this way: TZ setting as highest priority and nested enabled, it first shuts down ePWM1A, then interrupt responses and software delay 2~2.5us, then shuts down ePWM2A.
Br, Jordan

0 Jordan Zhou over 6 years ago in reply to Nima Eskandari

TI__Genius 10120 points

Any comment?
Br, Jordan

0 Nima Eskandari over 6 years ago in reply to Jordan Zhou

TI__Guru 52040 points

The problem is if you set up both the CBC and the OSHT, looking at the diagram below,

If a CBC event has occured, the OR GATE will ignore the OSHT event and vica versa. Not only that, you get only of action on OSHT/CBC TZ event.

These two problems wont let you do both CBC and OSHT using just the tripzone module with flexibility.

What you can do is use the TZ module in CBC mode, then use the DC module in OSHT mode.

They can each have independent actions defined for them in the TZCTL register.

0 Jordan Zhou over 6 years ago in reply to Nima Eskandari

TI__Genius 10120 points

Nima,
Yes, you are right.
But, in this case, can we "3) During "one shot" or "CBC", ePWM1A is always shut down first, 2~2.5us later ePWM1B shut down"?
Thanks a lot.
Br, Jordan

0 Nima Eskandari over 6 years ago in reply to Jordan Zhou

TI__Guru 52040 points

Okay for hardware delays, take a look at DCEVTFILT and valley switch with the delays.

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28377S: ePWMxA and ePWMxB are controlled by different TZ