Hi All,
We are on a new board with on-board XC3S250E-VQ100.
All VCCint are 1.2V All VCCaux are 2.5V Bank0 VCCio are 3.3V Bank2 VCCio are 3.3V
Bank1 VCCio are un-driven (not powered) Bank3 VCCio are un-driven (not powered) Bank1 VCCio and Bank3 VCCio are connected together
We can see a strange issue on VCCio of bank1 and Bank3 if they stay un-driven (not powered). We can see a voltage of 4.64V on Bank1 VCCio and Bank3 VCCio.
Now if we charge a 200ohm resistor on Bank1 VCCio we can see a voltage of 4.05V on Bank1 VCCio and Bank3 VCCio.
Are there something wrong with our Spartan3E! Why this 4.64V ?
Please help to understand.
Regards, Laurent