What's the reason for XST warnings about overused bonded IOBs?

[555lin]

Guys, tell me please in which case should I list all the signals in the process and
in which case not all of them?

After synthesis in XST I got number of bonded IOBs overused 133%. I don't
quite understand what can be the reason for this.

 

[tkbits]

Re: XST warning question

The number of IOB's is related to the number of pins you will use. Thus it is determined by the number of input/output signals in the top level module.

The number of pins you will use is a design choice, so either you are asking for too many pins for the chip you're using, or your chip is too small for your design.

 

[amitgangwar_vlsi]

Re: XST warning question

check the device manual or data sheet...
in your design number of input and outputs are greater than the
available i/o pins on device.........

 

[FrankCh]

XST warning question

You may need to remove some unnecessary IO pins or simply use a larger FPGA chip.