TMS320F28388D: Can the CLB be used as a transmit Shift register?

Hector Aguirrebeña

Hi, some context here

For a while, I have been using the CLB as a reception shift register for reading absolute encoders, meaning that I read a data pin into two counters stacked together in serializer mode and capture data up to at least 64 bits. This is great.

However, an issue is posted in this forum, and I have encountered it myself, that the values of the counters cannot be written while the counters have an event linked that is not "Load" or "None".

Is there a way these counters could be used as transmission shift registers (in other words, pre-loading a value in the counters and shifting them to the output bit by bit?). Maybe dynamic reconfiguration of the counter load mode could work here?

Best regards

over 4 years ago

0 Nima Eskandari over 4 years ago

TI__Guru 52220 points

You can use the SERIALIZER mode I believe!

0 Hector Aguirrebeña over 4 years ago in reply to Nima Eskandari

Prodigy 10 points

Hi Nima,

I am asking because apparently the HLC cannot write the counters when the counter event is set to Shift. With serializer, the event is set to shift, thus this cannot be done. See the linked post

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/1011909/tms320f28379d-clb-hlc-register-to-counter-write-problem

Can you confirm if this would be possible or not in CLB type 2 ?

+1 Nima Eskandari over 4 years ago in reply to Hector Aguirrebeña

TI__Guru 52220 points

Not the event mode = SHIFT.

I'm talking about, event mode = LOAD.

Then enable the type 2/3 serializer mode.

0 Hector Aguirrebeña over 4 years ago in reply to Nima Eskandari

Prodigy 10 points

So, if I understood correctly,

In serializer mode, will the counter shift data regardless of the event mode?

0 Nima Eskandari over 4 years ago in reply to Hector Aguirrebeña

TI__Guru 52220 points

Hector,

I have not tested this. From my previous conversation with design, the load mode was the requirement to allow HLC to load. I think this may work. Can you try it out?

Nima

0 Hector Aguirrebeña over 4 years ago in reply to Nima Eskandari

Prodigy 10 points

Hi Nima,

It seems that the serializer works even when the Event is different from shift, so this solves my issue. Thank you very much.

0 Nima Eskandari over 4 years ago in reply to Hector Aguirrebeña

TI__Guru 52220 points

PERFECT! Glad it works.

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TMS320F28388D: Can the CLB be used as a transmit Shift register?