Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

The MSEL pins are powered by VCCINT

1)I am using EP3C25E144,it has MSEL[2..0],from tha datasheet see that "The MSEL pins are powered by VCCINT",but when I design the PCB ,i only saw that keep them '101' is Fast Active Serial Fast (AS F...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

thanks so much for your replies.

Maybe through the words above i supplied,also pointed out a problem you met before .

"The MSEL pins are powered by VCCINT",didn't it mean hardwire the MSEL to VCCINT (1.2V)if want it to be high?

"Hardwire the MSEL pins to VCCA or GND without any pull-up or pull-down resistors to avoid any problems detecting an incorrect configuration scheme."i understood it as that it recommended us hardwire the MSELs to VCCA(2.5V) ,yes?

and now ,i harewire the MSELs to VCCIO(3.3V) on my PCB board.

as FvM said "the difference between using VCCA (as suggested by Altera for Cyclone III) and VCCIO (as it has been ususal with previous FPGA families) won't matter much." but actually some unexpected (http://javascript<b></b>:void(0)) problem would happen and hard to check out for us. so thought it was a confusion for me(maybe us)to decide which VCC to use .