[Arty A7 25MHz device for Ethernet]

On 6/9/2023 at 1:18 PM, zygot said:

It makes a big difference if you are talking about the Arty A7-35T or the 100-T versions.

Is there a reason why you'd want an external clock for a low speed Ethernet PHY?

I am asking about Arty A7-100T

Yes, I want to decouple the clock subsystem from the precise 25MHz needed for Ethernet PHY.  As it is designed, the entire clock tree has to be constrained to multipliers that can source a precise 25MHz as an output.  It also burns a clock route, and adds constraints I'd rather not fuss with in fabric.

Make sense?

[Arty A7 25MHz device for Ethernet]

On 6/9/2023 at 3:54 PM, asmi said:

I suspect he means exactly what it sounds like. There is a footprint for 25 MHz crystal (not clock chip) X1, as well as two load caps (C114 and C115), which are not actually placed, and a zero Ohm resistor R201 which will need to be disconnected if crystal is to be installed. So if you install X1, C114 and C115 and remove R201, you can make PHY work off that crystal without having FPGA to provide clock. Not sure why one would want to do that, but it is possible.

Yes this is what I want to do.  The reason to use external 25MHz clock is to decouple the PS/Fabric clock subsystem from the (precise) 25MHz needed for the Ethernet device.  

[Arty A7 25MHz device for Ethernet]

I would like to utilize an external clock for Ethernet.  The 25MHz clock chip has an existing footprint on the board. 

What is a suitable device to order for this purpose?  

[To Digilent employees: is there any chance to update the tutorial "Arty - Getting Started with Microblaze Servers"?]

I wanted to say that I would like to get this demo up as well.  I am looking forward to your update.

[USB HID -> PS/2 PMOD board ?]

I would love to see a PMOD USB to HID that could work as either a controller (takes input from HID devices) or as a slave (meaning, it acts like a keyboard or mouse)

The pro micro arduino does this and I have one.  It's pretty great, but not in a PMOD format.