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Altera_Forum
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16 years ago

Do Altera Cyclone III FPGAs have an internal oscillator?

I am new to this. I would like to use if Altera Cyclone III FPGAs have an internal clock (oscillator) that I can use. Or am I required to use an external clock input? Thanks
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Hi,

The CIII fpga is designed to use a external clock source. The internal clock source OSC mentioned in the literature is not available to the user design only for internal startup operations of the FPGA. Technically you can create a ring oscillator with inverters as a hack, but the quality of clock would not controlled compared to using a external clock chip which has clear timing specifications.