Communication between Spartan 6 FPGA and Raspberry Pi 3 model B

Question

As a part of my project, I need to transmit information between raspberry pi 3 model b and Xilinx spartan SP605 evaluation board FPGA via ethernet. I want this over ethernet because we want to send information at around 100 Mbps/1 Gbps. Could anyone suggest some example codes for raspberry pi in order to initiate the connection between it and FPGA?

michaelkellett · Answer

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

michaelkellett · Answer

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

michaelkellett · Answer

Hello Nithin,

This is kind of looking like "Please do my homework" kind of discussion.

You need to learn about Ethernet (you can try Google but you would do better by obtaining and studying the first few chapters of "TCP/IP Lean" by Jermey Bentham, concentrate on understanding UDP protocol)

Then you need to learn how to talk to Ethernet via Python (or some other high level language but Python is your best bet for the Pi) (google: UDP Python)

There are no shortcuts here, you are 4 weeks of study (at least) from understanding why the question you have just asked about MAC level makes no sense.

PCs and PIs talk on the Ethernet using protocols - they deal with MAC level messages at a much lower level and unless you are going to write your own Kernel drivers you are not going there. On the FPGA you will have to go there unless you use a soft processor and and OS.

Whoever is asking you to approach the problem this way is not helping you much - you need to understand Ethernet a good deal better than you seem to before hitting it with an FPGA (which is just about the hardest way to do it - I don't know any one who started with that.)

MK