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Altera_Forum's avatar
Altera_Forum
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18 years ago

Cyclone II and NIOS frustrations

I have an EP2C20 on a new board that I'm trying to debug, and am having very strange problems. I am using a USB Blaster. Initially, the Quartus programmer would download the configuration, but...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
18 years ago

I had a similar type problem with downloading via the USB Blaster. I finally found that I had a signal integrity problem on the TCK line. The signal had a slight "shelf" around the threshold that I only found after looking at it with a Ghz scope. If you look at the Cyclone II NIOS Dev. Kit you will notice a 10pf cap(C556) on the TCK line. After adding this capacitor( it needs to be adjacent to the TCK pin), my problem was resolved.