Simple way to show ethernet packet timing on scope

[LapTop006]

Interestingly that Phy has a mode where you can tie two of them back-to-back to act as a repeater - that plus an FPGA might have some interesting applications for low-level realtime man-in-the-middle & fuzzing applications without any buffering delays you'd get using a normal ethernet interface.

Handy for electrical to optical converters & similar. Similar designs are used by some simpler wavelength division multiplexing systems.

[mikeselectricstuff]

https://youtu.be/SYnO9CsTEqQ

[benSTmax]

Thanks for another great video.
One other option for a cheap HW decoder might be to use the DP83848 in back to back mode and a CPLD/small FPGA for decoding the RMII.
DP83848 provides a demultiplexed RX_DV signal which can be connected straight to the other's TX_EN. Then, the CPLD can decode both data streams and capture the traffic both ways.
Check chapter 6 at the following link:
http://www.ti.com/lit/an/snla076a/snla076a.pdf

[t1d]

This is not my area of expertise, but would one of those $7 Ebay Logic Analyzers, with free Sigrock and PulseView programs, help? They actually have a descent rep. I have not used mine, yet, but it is rather well made. See YouTube instruction videos.

The programs are here: https://www.saleae.com/downloads/ Saleae is aware that people are using their free software with this cheap devices and seem to be unconcerned, due to selling professional grade equipment.

Example only. I know nothing of this vendor.
https://www.ebay.com/itm/Useful-ARM-FPGA-New-8CH-USB-Cable-Debugging-Tool-Logic-Analyzer-Analysis-Device/173622196213?epid=6025499068&hash=item286cb077f5:g:-IMAAOSwEJZb3j70:rk:10:pf:0

[cdev]

I am almost 100% certain that one can't use a cheap logic analyzer to decode Ethernet.

Also, the designs for inexpensive Fx2 logic analyzers, including the various commercial vendors I am pretty sure, were all based on the original dev board reference design from the chip manufacturer. Or so Ive heard. That doesn't make it morally right to use their software without having bought their hardware. Still, its important to recognize that the company that makes the chips the logic analyzers use, wanted people to buy them in quantity so they made a great reference design.

Then several companies brought logic analyzer designs to market that were all functionally similar to that reference design. Both Saelae and usbee were quite successful for a while but eventually their low end products were impacted by widespread availability of clones which were built in cheap cases or came as bare boards without slick rainbow colored mini grabbers.. but still did the job.

People do have a choice of using a really good piece of free software, pulseview, for them which is part of the sigrok suite.

 Sigrok software (sigrok.org) for the FX2/FX2LP chipset is totally free and quite feature rich.

Compatible mini logic analyzers can be bought for $10 and up.

Although at least one of the hardware companies now sells their commercial program as an add on for people who dont own their hardware, a business model that I like, that works with my LA (usbee) and comes with support, and Ive thought about it, I still have not pulled the trigger because to date, I am not so proficient yet, I am still mucking around so I have never needed to, not having outgrown the capabilities of the free software yet.

[t1d]

I am almost 100% certain that one can't use a cheap logic analyzer to decode Ethernet.

Thanks for that clarification edit, because I wasn't quiet sure what I was in error about. Yeah, I didn't know, if it would be helpful, but I was trying to be helpful;-)

That doesn't make it morally right to use their software without having bought their hardware.

Agreed. And, if I had not seen an article about Saelea's position, I would not have downloaded their program. I'm sorry, but I did not bookmark the reference. I did watch the PulseView author's YouTube video and, IIRC, it is open source and he has turned over its continued development to the community. But, it has been a good long while, since I looked at this stuff.

Thanks, for the info. It was interesting.