Cyclone III and JTAG programming problem

Altera_Forum · ‎03-18-2009

Hi everybody,

I have a problem concerning programming my Cyclone III device. I have a original USB Blaster cable which for sure works fine. The problem is that when I try to use it, Quartus responds that device is not found.

I use it on a board that was designed by me so maybe there are some mistakes, but I don't know what else to check. I've already checked all the connections, voltages etc, they seem to be fine.

Any ideas?

Altera_Forum · ‎03-18-2009

Apart from incorrect connected JTAG interface, the most popular design faults with Cyclone III are:

- missing GND connection of exposed pad with EQFP144 package

- missing 2.5V supply for VCCA

Basically, the JTAG interface is kept in reset, until VCCINT and VCCA reach a minimum level. Also the exposed pad's GND connection is required for operation.

Altera_Forum · ‎03-18-2009

Thanks. I think exposed pad is an issue, since it is the first time I hear of it!

I'm a complete beginner...

Altera_Forum · ‎03-18-2009

It's only present with 144 pin package, not with 240 pin or any BGA version.

Altera_Forum · ‎03-18-2009

Oh yes, I know, and this is the case. I'll try to fix it tomorrow, keep your fingers crossed ;)

Altera_Forum · ‎03-18-2009

Depending on the board layout, you may be able to create a connection to the exposed pad by carefully milling a hole into to the assembled board. Forum members already have reported a succesful repair.

Altera_Forum · ‎03-20-2009

It works! Board looks quite weird with such a hole, but this is not that important... Thanks a lot!