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Altera_Forum
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13 years ago

I2C interafce on DE1 board

Hi, I'm trying to use the I2C opencore provided by the alterawiki with an Altera DE1 board. I am using Quartus 11 and SOPC builder and I am able to create a SOC system with a NIOS II processo...
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Altera_Forum
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13 years ago

An I2C controller only ever drives low. The I/O pins require pull-ups. In your case, just enable the weak pull-ups on the GPIO pins you assigned the I2C signals to, and you should be able to see the signals driven low by the controller, and then slowly go back to being high when the controller tri-states them. Depending on your application, you will probably require stronger pull-ups, eg., 4k7 resistors. However, using the weak pull-ups will at least help you realize it is working.

Cheers,

Dave