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Altera_Forum's avatar
Altera_Forum
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15 years ago

default voltage for the cyclone 3 why is 2.5

when i consult the cyclone 3 datasheet,the VCCIO for c-3 is 3.3V,but when set the pin planner in QUARTUSII or the menu of assignment->device/ device and pin options/voltage tab:default I/O standard i...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

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Ie, if you want to use 3.3V LVCMOS I/Os, the bank's VCCIO must be 3.3V.

OTOH, if you want to use LVDS signals, the I/O bank's VCCIO must be 2.5V.

Therefore, you can't mix 3.3V LVCMOs and LVDS signals in the same banks.

You need to use different banks.

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yes ,that was what i mean,and i think i get it now.thanks