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Altera_Forum's avatar
Altera_Forum
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19 years ago

Cyclone II programming problems

Hi all -- I've built a few PCBs based on Cyclone II FPGAs. Some of these boards, and especially the last, suffer from an annoying problem: When connecting the FPGA to the JTAG cable, Quart...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

I really appreciate your effort for helping others. The ideas you give me show me you really know what you're talking about, so it's even rarer that people like respond to questions in forum.

However, after spending a few more hours on the problem, it showed up that there was some small error (isn't it always a small error?). I'm powering my board using a source where I can limit the current, so in case I have a shortcut I don't smoke my board and supply.

I set the current limit about 100mAmps above the idle state. Without being able to tell by looking at the source, the CycloneII requires a current boost of well over 150mAmps immediately after configuration. My source clipped the current, so the FPGA must have reset itself. By simply putting the current limit a few mAmps higher, the problem is solved.

Again, thanks for your answers and ideas.