Altera CPLD - Illegal assignment-global clock

Jan 05, 2004 2 Replies

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J.F. FOURCADIER 22 years ago

Newbie

I try to use an Altera CPLD EPM7064. When I try to connect a register clock input to a normal pin, I get the message "Illegal assignment-global clock'input_clock' on pin 31. I understand it's better to connect this kind of input on a dedicated clock pin, but I cann't for wiring reasons.

The data sheet indicates a programmable register can be clocked by signals from buried macrocells or I/O pins. How can I get this result ? I work on the the graphic editor.

Thank you for your help !

Jean-François FOURCADIER, F4DAY

website :

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Mike Treseler 22 years ago

On the 7064, the only route to the internal clocks is through the special pins.

You may have to bend up a pin and solder a wire.

-- Mike Treseler

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Dejan Durdenic 22 years ago

You have probably checked "Automatic Global Clock" in the "Global Project Logic Synthesis" window - that will assign your clock to the global clock input pin.Uncheck it, and you can route your clock where you like (although there will be a speed penalty, of course).

- Dejan

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