F28M35 : EPI bus from C28x subsystem

Hi Joel,

Joel Soares said:

Does it mean the use of the EPI bus is possible but not recommende

Above statement is valid only for C28x and not for M3 core. You can interface FPGA with M3 core by referring this example: epi_sdram

C:\ti\controlSUITE\device_support\f28m35x\v160\F28M35x_examples_Master\epi_sdram

Regards,

Gautam

Hi Gauam,

Thank you very much for your answer,

I understood that EPI bus works fine with M3 subsystem.
But, can you tell me if it is reasonable to use the EPI bus during critical time interruption of the C28x.
I would like to "quickly" writte and read data on the FPGA from the C28x SUBSYSTEM.

Regards.

Joel Soares said:

But, can you tell me if it is reasonable to use the EPI bus during critical time interruption of the C28x.
I would like to "quickly" writte and read data on the FPGA from the C28x SUBSYSTEM.

I really don't think this is possible as it clearly indicates in the above extract. Also, you cannot find any examples on EPI interface through C28x core as EPI peripheral is a part of M3 core. Hence what you can do is, share the C28x data with M3 through IPC and then use EPC for FPGA communication.

Regards,

Gautam

Thank you for your answer

Whe can read on Literature Number: SPRZ357J "Silicon Errata" p36 :

****************************************************************************
****************************************************************************
Advisory EPI: C28x Access to the EPI Bus on the Device

-Revision(s) Affected 0

-Details On Revision 0 silicon, the Control Subsystem (C28x core) cannot access the EPI. Only
the Master Subsystem (M3 core) can.

****************Starting with Revision A silicon,**************
the C28x has read and write data access to the EPI peripheral.

-Note that C28x use of the EPI for program
execution is not supported in any silicon revision.

-Workaround(s) This is fixed in Revision A silicon.


****************************************************************************
****************************************************************************

It is clearly written that the EPI bus :
1-can be used by the C28x core
2-but the C28x use of the EPI for program
execution is not supported in any silicon revision.

What does it mean ?

1- This function is operational on the C28x for industrial applications. But TI has not had time to document
2 -This function is operational on the C28x for prototype applications. But TI does not recommend for industrial applications


Regards

Joel Soares said:

1- This function is operational on the C28x for industrial applications. But TI has not had time to document
2 -This function is operational on the C28x for prototype applications. But TI does not recommend for industrial applications

Sorry, Joel... I won't be able to comment on the above questions. I would prefer a TIer to answer these. Please be patient.

Regards,

Gautam

Hi Joel,

Sorry, I didn't understand the confusion here. Document clearly mention that  C28x core can use EPI for READ/WRITE access to external device like RAM or FPGA. What is not allowed is execution of code sitting in external device.

So in this case as long as you need to just READ or WRITE data into FPGA, it is fine. I'll check on the sample code in controlSUITE.  Please do let us know if you have any further queries on this.

Regards,

Vivek Singh

Hello,

Thank you for your answer.

It's a good think to be able to read and write data into FPGA from the control subsystem.

However on ControlSuite, I have not found an example for programming epi bus from the C28x.

Should I configure the epi bus from the M3 subsystem like in one of the epi sample code in controlSuite (epi_sdram or epi sram_8bits),

THEN use the epi bus from the C28x subsystem simply by writing or reading at an address.

Regards

Hello Vivek,

Are there any C28 demo codes that can realize C28 READ/WRITE access to external device via F28M35 EPI module? Cannot find it in controlSUITE. Thanks!

Best Regards,

Linda

Hello Linda,

This thread has been inactive since 2014. For your best chance at prompt support, please create a new thread. If there is pertinent information in this thread, you can link back to it in your new post.

Best Regards,
Adam Dunhoft

Hi Linda,

You are right. I do not see these examples in controlSUITE. I'll let SW team know about this.

Regards,
Vivek Singh