What could be used as the interface of AM5728 to add one FPGA as co-processor

We determined that PCIe was the only viable option for a high speed interface to an FPGA. Getting it to work will be a real challenge though as we are using the DSP for processing and not the ARM.

Hi Christopher,

Thank you so much for your reply. You used DSP to interface with FPGA? I suppose EMIF interface of the DSP can be used for the DSP+FPGA structure. I am now thinking about connect one FPGA to the ARM chip though.

Thanks, Yicheng

In an earlier 6482 based design we used the EMIF to connect to our FPGA. However, the new AM5728 has split the EMIF into the EMIF and GPMC. The new EMIF is designed to be dedicated to the DDR memory interface and the GPMC is more general purpose memory interface. The problem is the new GPMC is slower than the old EMIF was so it will no longer meet our needs, thus the change to PCIe.

So now you are using the PCIe interface to connect one FPGA to the AM5728? Will this PCIe capable for the interruption functionality to trigger the data transmission between the FPGA and the AM5728. In my case, the data direction is from FPGA to AM5728.

We are just starting the design phase, but yes that is the intent. We intend to use the PCIe to transfer data both directions hopefully using EDMA transfers. However, I understand the PCIe support in the new Processor SDK is very immature, so I am not sure how quickly we will have a solution for this. However, I believe we must make it work as no other high speed interface option exists.

BTW, we also used to use McBSP for a high speed interface to the FPGA, but that is removed and replaced by McASP on the AM5728 and McASP is not as flexible as McBSP was, so that is no longer an option for us.

It is the same here. We are just starting the design phase also. Actually my first guess is to use the McASP for the data transmission, since the data rate is not so high that has to go with the PCIe. I think I will put this two options in the design at the same time just to be secure. The GPMC requires too many signal connections which make it not quite suitable as the previous two approaches.

I thought we looked at McASP and saw that it is optimized only for Audio applications and could not really be used for general data transmission. If you know differently I'd like to hear your take on it.

I am now looking into the options now. Will keep you posted if I have some new findings.

Thank you.