TMS320F280039C: ePWM Time base counter sync phase calculation

Irene Boben

Part Number: TMS320F280039C

Hi Team,

I am trying to see if there is any direct formulae to calculate phase delay between two ePWM modules. When I configure ePWM in both UP mode or both in down mode, I see that phase delay is same as the calculation given in TRM i.e. phase Delay = TBPHS/TBPRD * 360

However, when I want the slave ePWM to be in up - down counter mode, I see that phase delay depends on the counter direction after sync, also the counting mode of the master ePWM.

My question here is, is there a direct formula for phase delay in case of up-down counting in slave?

over 2 years ago

0 Nima Eskandari over 2 years ago

TI__Guru 52020 points

Irene Boben said:
However, when I want the slave ePWM to be in up - down counter mode, I see that phase delay depends on the counter direction after sync, also the counting mode of the master ePWM.

Irene you are 100% correct. Unfortunately we dont have a formula but it should be doable if you put it together I can check it for you.

Now I do have a question, why is your slave PWM a different mode than the master? They have different periods?

0 Irene Boben over 2 years ago in reply to Nima Eskandari

Expert 1030 points

I was just checking different scenarios. I will check the behavior when both of them are up-down counting mode.

0 Nima Eskandari over 2 years ago in reply to Irene Boben

TI__Guru 52020 points

Sounds good!

0 Irene Boben over 2 years ago in reply to Nima Eskandari

Expert 1030 points

When both master and slave are up down counting mode, we cannot really deduce a formula as it depends on the direction slave takes after the sync. But a complete 360 degree phase change is achieved when TBPHS changes over 2*TBPRD unlike only UP or Down counting.

0 MatthewPate over 2 years ago in reply to Irene Boben

TI__Guru* 77460 points

Irene,

Nima is currently out of the office. Please expect a reply from him by this Thursday the 28th.

Best,

Matthew

0 Irene Boben over 2 years ago in reply to MatthewPate

Expert 1030 points

Sure. Thanks Matthew!

+1 Nima Eskandari over 2 years ago in reply to Irene Boben

TI__Guru 52020 points

Sorry for the delay! Once again you are correct with the item below.

Irene Boben said:
When both master and slave are up down counting mode, we cannot really deduce a formula as it depends on the direction slave takes after the sync. But a complete 360 degree phase change is achieved when TBPHS changes over 2*TBPRD unlike only UP or Down counting.

If you compile a bullet list I can add it to the TRM.

Nima

0 Irene Boben over 2 years ago in reply to Nima Eskandari

Expert 1030 points

Thank you Nima for the confirmation! I have not made a list as I was just trying different scenarios else I would have shared the same with you.

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TMS320F280039C: ePWM Time base counter sync phase calculation