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Altera_Forum
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11 years ago

Cyclone III EP3C25 - Pin 141 can't drive signal ?

Hello everybody I have a problem with a Cyclone III EP3C25E144I7N FPGA. I try to affect an output (UART_TX) to the pin 141. Observing it with a scope, the output stays at 1. When I ...
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Altera_Forum
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11 years ago

Have you tried driving some other signal out of this pin - such as the result of a simple register toggling every clock cycle or the clock itself?

You don't say what package you're using. However, assuming pin 141 is a standard I/O pin then it should behave as pin 144. Check that it isn't a pin with a reserved function or a dedicated clock input. Compilation should fail if you've incorrectly constrained it to such a pin, but worth checking.

A quick look at the packages shows pin 141 is perfectly valid if you're using an E144 package. However, it's a GND connection in the Q240 package - invalid. Again compilation should fail if you specify this.

Cheers,

Alex

Ammendment:

PS. I subsequently see you did specify the package you're using... :) So, it should all work as you expect.