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Altera_Forum
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18 years ago

Connecting 3.3V IO to 1.2V for pin compatibility

Hi, I am designing a board containing a CycloneII FPGA. I am not sure which part numer i should to use, 35 or 50. These two parts are pin compatible except that some pins are used as VCCINT(...
Altera_Forum's avatar
Altera_Forum
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18 years ago

You can still use a device wide assignment for your unused outputs to behave as "outputs driving ground". When you turn on Migration in Quartus II, the programming file will automatically set the I/Os as inputs - tristate for the pads which are VCC or GND on the larger devices.

Anytime you want to create a footprint to support multiple device densities, use Device Migration in Quartus II. The tools will take care of the pins which are I/Os in some densities, and VCC / GND in other densities. Then as Brad said, the .pin file will be your guide.