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Altera_Forum's avatar
Altera_Forum
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15 years ago

How to configure cyclone 3

I have questions to ask. 1.IN the figure, if the VCCIO supply of the bank in which nstatus pin resides is 3.3v,is the nstatus pin pull-up resistors voltages 3.3v in AS MODE?? 2.IN the fi...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Everything is answered in the hardware handbook. Unfortunately you didn't show the respective annotating text. Supplying the USB Blaster and respective pull-up resistors by VCCA (2.5V) rather than VCCIO (mostly 3.3V) is a special idea that Altera has introduced to reduce the risk of overvoltages at the FPGA pins. I expect that it's working correctly, but prefer to ignore it up til now and use clamp diodes at the JTAG pins instead. But in case of doubt, you should follow the Altera suggestions.