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Altera_Forum
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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

Please don't expect an explanation, but the device manual clearly suggests not to do what you intend. According to the manual, you should have pull-up and pull-down jumpers.

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A configuration scheme with different configuration voltage standards is selected by driving the Cyclone III device’s MSEL pins either high or low as shown in Table 10–1. The MSEL pins are powered by the VCCINT power supply of the bank in which they reside. The MSEL[3..0] pins have 9-kΩ internal pull-down resistors that are always active.

To avoid problems in detecting an incorrect configuration scheme, hardwire the MSEL pins to VCCA or GND without pull-up or pull-down resistors. Do not drive the MSEL pins with a microprocessor or another device.

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