TMS320F280037: What is EPWMCLK?

mokkun

Prodigy 560 points

Part Number: TMS320F280037
Other Parts Discussed in Thread: TMS320F28075,

Tool/software:

The datasheet and TRM mention "EPWMCLK" in many places, and I would like to know what it is.

In case of other device, e.g. TMS320F28075, it is quite obvious as it is shown below.

However, same figure in TMS320F28003x TRM(spruiw9c.pdf) does not show it as follows. (Is TBCTK[CLKDIV] Typo?)

And the explanations of the control bits for "Clock Prescale" block shown above says,

> These bits select the time base clock pre-scale value (TBCLK = EPWMCLK/(HSPCLKDIV * CLKDIV):

May I consider "EPWMCLK" in the above as SYSCLK shown in the block diagram?

One more part, I assume the magenta block in the following figure may need to be removed?

Regards,

over 1 year ago

0 Ryan Ma over 1 year ago

TI__Mastermind 27736 points

Hi Mokkun,

EPWMCLK is another name for the clock signal that comes after EPWMCLKDIV. Some devices have this clock divider that is outside of the ePWM module (seperate from CLKDIV and HSPCLKDIV).

For devices that do not have this EPWMCLKDIV, then the clock name will just be TBCLK.

Best,

Ryan Ma

0 mokkun over 1 year ago in reply to Ryan Ma

TI__Prodigy 560 points

Ryan, Thank you for your prompt reply.

> For devices that do not have this EPWMCLKDIV, then the clock name will just be TBCLK.

Assuming TMS320F280037 does not have EPWMCLKDIV, HSPCLKDIV and CLKDIV in the following equation have no effect?

TBCLK = EPWMCLK/(HSPCLKDIV * CLKDIV)

Regards,

0 Ryan Ma over 1 year ago in reply to mokkun

TI__Mastermind 27736 points

You can assume EPWMCLKDIV to be 1 for devices that "do not have" EPWMCLKDIV.

So that EPWMCLK == SYSCLK.

Best,

Ryan Ma

0 mokkun over 1 year ago in reply to Ryan Ma

TI__Prodigy 560 points

Ryan,

Sorry my question was not clear. By looking at the following block diagram,

I believe the following equation in the TRM

TBCLK = EPWMCLK/(HSPCLKDIV * CLKDIV)

should be corrected as

TBCLK = SYSCLK/(HSPCLKDIV * CLKDIV)

If "EPWMCLK == TBCLK" is applied to the above equation, it will be as follows and thus HSPCLKDIV and CLKDIV have no effect, and I assume it is wrong.

TBCLK = TBCLK/(HSPCLKDIV * CLKDIV)

Would you please let me know if I am correct?

Regards,

0 Ryan Ma over 1 year ago in reply to mokkun

TI__Mastermind 27736 points

Hi Mokkun,

Which version of the TRM are you referring to?

Apologize, I meant SYSCLK == EPWMCLK. Corrected above statement

Best,

Ryan Ma

0 mokkun over 1 year ago in reply to Ryan Ma

TI__Prodigy 560 points

Ryan, Thank you for your reply.

I am referring to TRM Version C.

https://www.ti.com/lit/ug/spruiw9c/spruiw9c.pdf

In "Table 20-24. TBCTL Register Field Descriptions",

the explanation of Bit[12-10] CLKDIV & Bit[9-7] HSPCLKDIV says

"TBCLK = EPWMCLK/(HSPCLKDIV * CLKDIV):". I believe I should read it as "TBCLK = SYSCLK/(HSPCLKDIV * CLKDIV):".

Therefore, only HSPCLKDIV and CLKDIV affects the frequency configuration of TBCLK made from SYSCLK.

Am I correct?

Regards,

0 Ryan Ma over 1 year ago in reply to mokkun

TI__Mastermind 27736 points

Hi Mokkun,

That is correct.

Best,

Ryan Ma

0 mokkun over 1 year ago in reply to Ryan Ma

TI__Prodigy 560 points

Ryan, Many thanks for your all of your help.

Now, the relationship between TBCLK and SYSCLK is very clear to me.

May I ask you another question here? Please let me know if I should use another thread.

TMS320F28003x TRM(spruiw9c.pdf) shows EXTSYNCIN1&2 go to "ePWM Sync Scheme" as follows.

Figure 20-3. ePWM Modules and Critical Internal Signal Interconnects

My question here is, How EXTSYNCIN is used to generate EXTSYNCOUT.

"20.4.3.3 Time-Base Counter Synchronization" mentions EXTSYNCIN1&2 but "Figure 20-7. Time-Base Counter Synchronization Scheme" does not show it.

Would you please help me to understand?

The following is just FYI, F28075 TRM (spruhm9h.pdf) mentions the relationship between EXTSYNCIN and EXTSYNCOUT very clearly as follows.

Regards,

0 Ryan Ma over 1 year ago in reply to mokkun

TI__Mastermind 27736 points

Hi Mokkun,

Can you please open another thread on these questions. These are good sync questions that may help another user.

Best,

Ryan Ma

0 mokkun over 1 year ago in reply to Ryan Ma

TI__Prodigy 560 points

Ryan, Thank you for your reply.

I have opened the following. Please close this thread.

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1378184/tms320f280037-relationship-between-extsyncin-and-extsyncout

Thank you in advance for your continuous support.

Regards,

+1 Ryan Ma over 1 year ago in reply to mokkun

TI__Mastermind 27736 points

Hi Mokkun,

Can you mark this thread as resolved? We will support your other thread.

Best,

Ryan Ma

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TMS320F280037: What is EPWMCLK?