AM6442: Four Ethernet Interfaces with GPMC

Hello Stuart,

Thank you for the query.

Please refer below

https://www.ti.com/lit/an/spradh8/spradh8.pdf

Please share the PINmux.

I suspect the above configuration you mentioned could result in resource conflict.

Regards,

Sreenivasa

Sreenivasa,

Pretty much any combination I try, and GPMC mode, results in a conflict starting at GPMC address line 3.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/791/AM64_5F00_4ETH_5F00_GPMC.syscfg

I'm pretty sure this is not possible, and looking for confirmation that I haven't missed something to make it possible.

Thanks,

Stuart

Hello Stuart,

Thank you for the inputs.

I agree with you on the resource conflict.

Let me check with experts one more time.

Regards,

Sreenivasa

Hello Stuart,

Was there some preferences in terms of interfaces - RMII, RGMII, MII etc.

Regards,

Sreenivasa

On the PRU-ICSSG switch, RGMII is required. On the other two ports, any interface may be used (RMII, RGMII, MII), the requirement is 10/100, RMII is preferred because that is what the existing design this replaces uses today to communicate directly with an FGPA without a PHY in between..

Thanks,

Stuart

Hello Stuart,

Thank you.

There seems to be conflict with the configuration on a high level.

Do you know the GPMC configuration that customer wants to use.

The number of pins used changes with the GPMC interface configuration and not sure if that would help

Regards,

Sreenivasa

They can be flexible with the GPMC interface, but I could not find any combination of data width, synchronous or non-synchronous, muxed or not-muxed that didn't have address line conflicts starting at address 3.

Thanks,

Stuart

Hello Stuart,

Thank you.

Regards,

Sreenivasa

Hello Stuart,

If customer can use one 1 CPSW Ethernet port and 3 ICSSG ports, they may be able to use GPMC.

This is going to limit the number of PRU IOs that may be available.

Not sure if that is an option.

Regards,

Sreenivasa

Sreenivasa,

Thank you for the suggestion. We did already look at this. Unfortunately they need to use one of the PRU-ICSSG subsystems for another custom interface, and it is not available for Ethernet usage.

Thanks,

Stuart

Hello Stuart,

Thank you.

I do not have any additional inputs. 

Regards,

Sreenivasa

An external SPI MAC is also not a great option here. The likely path forward will be to use an interface other than GPMC. The candidates under consideration include:

• PCIe
• OSPI
• SPI
• FSI

We wanted to ensure that GPMC was not an option before pursuing an alternative path. I think we've concluded on that investigation.

Thanks,

Stuart