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AR# 63535

CoolRunner-II - What is the state of the I/Os when Vccint is powered but Vcco is not?


When a CoolRunner-II is programmed with the Vccint powered and the core active but the Vcco is not powered, what is the behavior of the inputs?


The behavior of the I/Os in this scenario is unpredictable. 

The outputs will be 3-stated with a weak pull-up to Vcco but the inputs are undefined. 

If this causes an issue in the design, it can be resolved by resetting the design once Vcco is powered and stable or by ensuring that Vcco is powered before Vccint.

AR# 63535
Date Created 02/10/2015
Last Updated 02/13/2015
Status Active
Type General Article
  • CoolRunner-II