Communication between Spartan 6 FPGA and Raspberry Pi 3 model B

As far as I know it can't be done,

https://www.raspberrypi.org/magpi/raspberry-pi-3bplus-specs-benchmarks/

The Pi 3 B+ tops out at about 200 Mbits/s.

The Pi4 is a bit faster but can't get near the potential bus speed of Giga bit Ethernet.

Once you have the data in the Pi, what do you expect to do with it ?

The only scheme I have heard of is to use the camera interface but this will take alot of work and need you to write your own drivers.

You would do much better to do some data processing in the FPGA and reduce the rate needed between it and the Pi.

If you want to get an FPGA talking over Ethernet you will need a PHY chip and some FPGA IP in the shape of a MAC and some way of handling the data.

If you explain your project in more detail it might be possible to help more effectively.

MK

Hi,

The main motive of my project is I need to control a device which requires 16 analog input voltages.I want to send this control information from Xilinx Spartan SP605 FPGA which has an ethernet MAC IP provided by Xilinx Logicore.

Hi,

That is I need to have fpga talking over ethernet.We are OK with 100 Mbps ethernet connection.

Ok - so you want to send data from FPGA -> PI Ethernet at < 100Mbit/s.

Which FPGA board are you using or will you design your own ?

What data rate do you need to support (ie how fast are you sampling the analogue inputs).

Is it a streaming application ?

Are you using a softcore processor on the FPGA ?

MK

Since you are connecting the PI to your FPGA via Ethernet this is all dependant on your networking. You'll need to elaborate on the application and how you re intending to talk to the Pi e.g. TCP or UDP stream and what do you want the PI to do is it processing Display or what ?

Example code is basically writing the app for you !

Raspberry pi just needs TCP/IP code. What to do with the data is another story. But here is the example looking at sensoraps . But the top speed is less than 80% of the rated speed of Ethernet if virtually no other usage of the network and knowing the Pi handicaps the connection even more because of the shared nature with USB. So maybe you will not achieve the 100Mbps, but much less.

Clem

TCP is rarely a good way of handling a streaming application, especially if one end is a low end FPGA.

UDP is not that hard to do in the FPGA fabric - TCP is hard work - most people either pay for expensive IP or use either an embedded hard or soft core processor, running a full blown OS.

For a streaming link between two devices in the same room, and with a requirement to operate close to wire speed (ie 50% or above) then UDP is often a better choice.

MK

Have you considered something Zynq based where the ARM core running Linux and the FPGA are on the same device?

Good idea David, although if been coupled with ethernet is good enough then it could all be a bit much. Really we would need to know what he's doing to give a sensible answer.

An Arty based design may be good too!

Michael, I'm not sure if many know how much in system resources TCP can take in maintaining all the connection orientated  stack including copies of the data if you need to perform a retry on a failed packet. With UDP you just need to assemble the packet and then be shoved out the pipe