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Altera_Forum
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12 years ago

PLL Megafunction actual clock frequency

Hi, I am using the Altera PLL Megafunction to generate 6 different clocks (100, 125, 200,50, 1MHz) with a reference clock of 100 MHz. I set all the frequencies correctly except for the 1 MHz c...
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Altera_Forum
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12 years ago

It looks like you're using a Cyclone V PLL, whose minimum output frequency is 5MHz.

Like FvM stated - don't drive logic with such a slow clock. Use a faster one (e.g. 100MHz), count the appropriate number of clock cycles (e.g. 100) and perform an operation each time your counter wraps.

If you need a 1MHz 'clock' signal out of a pin you can generate it in a similar way, by counting clock cycles and toggling an output register appropriately.