How to modify an existing Simulink TI C2000 ePWM block?

I would like to change the ePWM up-down counting direction (PHSDIR) online on a synchronization signal and set the TBPHS parameter to the last TBCTR+1 value before synchronization. This apprach was suggested by TI support when I asked how to implement a different PWM algorithm.

Currently, in the ePWM block, a PHSDIR is hard-coded, i.e. I am not able to change direction (count-up or count-down) online and there is no TBCTR output.

#1

Is it possible, and how, to modify an existing Simulink TI C2000 ePWM block to get those two signals?

Thank you in advance.

Edit:

#2 (another approach)

After reading through a few more threads, one of the solutions could be using the Memory Copy block. The idea is to trigger the sequence to read ( from source):

EPwm1Regs.TBCTR // read the value

and then update (to destination):

EPwm1Regs.TBCTL.bit.PHSDIR // change direction

EPwm1Regs.TBPHS.half.TBPHS // update with TBCTR + 1

for ePWM1, etc.

In the block help, it says the address input expects either the decimal address or the address as a hexadecimal character vector.

How to know the address of EPwm1Regs.TBPHS.half.TBPHS? Is there a list of registers and memory addresses available?

Answer 1

[Antonin]

Hi Mike,

As explained on the following page:

https://www.mathworks.com/matlabcentral/answers/1861853-using-a-memory-copy-block-to-read-write-a-single-bit-gives-an-error-and-workaround-not-working

You need to use the Memory Copy block with code symbol and the .all notation.

For example: &EPwm2Regs.TBPRD.all

As an alternative, you can use a function-call subsytem and use a Simulink Coder custom code block "System Output" where you can write the custom code you need. You can find this block in the Simulink Library Browser, under Simulink Coder > Custom Code > "System Output". This block will work in an atomice subsystem like the function-call subsystem. This technique will allow you to write any custom code but doesn't allow easy interaction with Simulink signals present in the model.

I hope it helps,

Thanks,

Antonin.