TMS320C6678: Question about the C6678 16bit EMIF access.

Denny%20Yang99373

Expert 3805 points

Part Number: TMS320C6678

Hi all,

If I use 2 dsp core, core0/1 to access 16bit EMIF at the same time.

Each one do 32bit read like below:

DSP0 32bit read; at the same time DSP1 32bit read;

Each 32bit will been divide to 2 16bit access. My question is if it is possible the DSP0 32bit read will been interrupted by DSP1 32bit read?

Does the 32bit read is atomic operation?

thanks !

BR,
Denny

over 6 years ago

0 Yordan Kovachev over 6 years ago

TI__Guru**** 161600 points

Hi,

Are you running any operating system on your device or is this done in bare metal code?

Best Regards,
Yordan

0 lding over 6 years ago in reply to Yordan Kovachev

TI__Guru* 95265 points

Denny,

I am checking with our C66x expert and will post here.

Regards, Eric

0 lding over 6 years ago in reply to lding

TI__Guru* 95265 points

One info I found here is: e2e.ti.com/.../553810 but it is inconclusive...

Regards, Eric

0 Denny%20Yang99373 over 6 years ago in reply to lding

TI__Expert 3805 points

Hi Lding,

That means customer should add semaphore to do the protecting?
Customer use bare metal software.

BR,
Denny

0 lding over 6 years ago in reply to Denny%20Yang99373

TI__Guru* 95265 points

Denny,

In that E2E thread, it discussed "So let's assume 2 CPU cores issue a 32-bit read transacation each (at the same time). I'd expect that a 32-bit transactions is"atomic" on the TeraNet switch and thus should be properly serialized the interfaces which lead to the EMIF16. Which hardware instance would be responsible for transforming this into a sequence of 4 interleaved 16 bit transactions">>>>>

This is not inclusive. If a 32-bit transaction can break into 2 16-bit, you need semaphore protection. If not, several 32-bit transactions just serialized. Then the semaphore is not required.

I asked our C66x expert if a 32-bit transaction is serialized or break and will update here.

Regards, Eric

0 lding over 6 years ago in reply to lding

TI__Guru* 95265 points

Hi,

We recommend you add semaphore to do the protecting.

Regards, Eric

Processors

Processors forum

TMS320C6678: Question about the C6678 16bit EMIF access.