Forum Discussion
Honored ContributorWeird EyeQ Output from Arria 10 Transceivers
Using TTK on an Arria 10 GX, I am noticing some vertically asymmetrical eye diagram output from EyeQ. I am stumped as to what could be causing this? Anyone seen something similar before?
http://www.alteraforum.com/forum/attachment.php?attachmentid=11083&stc=1 This seems to happen to any transceiver I use. If I use Serial Loopback, the eye still seems asymmetrical. http://www.alteraforum.com/forum/attachment.php?attachmentid=11085&stc=16 Replies
Altera_ForumGenerally the EyeQ would show the shape of the received eye diagram. Probably the actual eye is asymmetrical. Have you probe the eye diagram with scope to compare?
- Altera_Forum
Does anyone know if there was a problem with the ODI/EyeQ circuitry in Arria 10? All mention of OID/EyeQ was scrubbed from the latest release of the Arria 10 Transceiver PHY User Guide.
Carsona - Did you ever figure out what was wrong with your eye diagrams above? Thanks, Bob - Altera_Forum
Yeh turned out it was a ES2 silicon bug as informed by an Altera engineer. Using production parts along with Quartus 16.0 solved this - I get proper eye diagrams now.
- Altera_Forum
Thanks for the response. If it was just an ES2 problem why did they eliminate all mention of it in the Arria 10 docs and Arria 10 is not even listed as a supported family for EyeQ in the TTK:
https://www.altera.com/products/design-software/fpga-design/quartus-prime/features/swf-transceiver-toolkit.html Trying to get an official answer from our local Altera folks. - Altera_Forum
I've asked my local FAEs too. Strange.
- Altera_Forum
From local Altera transceiver expert via email:
"The EyeQ feature uses an INI variable in 16.0 and later to enable it. Many customers want to use this to make quantitative measurements but its accuracy does not lend well to this. For this reason to cut down on support it was made into a by-request feature. We don’t guarantee its performance. We do guarantee the BER testing capabilities provided by the ADME blocks and PCS and PMA, all of which are in the main XCVR datapath used by your logic." So it doesn't work as advertised but you can use it at your own risk (if you ask nicely).
