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hendwage's avatar
hendwage
Icon for New Contributor rankNew Contributor
5 years ago

Driving internal clock as input on Altera Cyclone II Board.

I'm currently implementing a stopwatch and already have the VHDL code. I've also set the buttons for start and reset. All that's left is to wire up my clock input which uses a particular freque...
EngWei_O_Intel's avatar
EngWei_O_Intel
Icon for Frequent Contributor rankFrequent Contributor
5 years ago

Hi there

The internal oscillator is used for initialization of FPGA and is disabled in user mode. It is not supposed to be used to drive user mode logic as there is some variation in the internal oscillator frequency because of the process, temperature, and voltage conditions in Cyclone II devices.

You can refer to document below for more details.

https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/cyc2/cyc2_cii5v1.pdf

I do suggest you to move to later device as most of the Quartus tools doesn't support this device anymore.

I hereby transition this thread to community support.

Thanks.