Answers Database
CPLD: XC9500/XL: How are unused I/O pins handled?
Record #1536
Product Family: Hardware
Product Line: 9500
Product Part: 9500
Problem Title:
CPLD: XC9500/XL: How are unused I/O pins handled?
Problem Description:
Urgency: standard
General Description: How do you handle unused pins of a XC9500 device?
Solution 1:
Xilinx recommends tying any unused pins to either the board ground or to a
board trace. This will help reduce problems associated with ground bounce and
noise.
Unused I/O pins in the XC9500/XL devices are tristated with a weak pullup.
However, with the M1.x/2.1i software. there is a "Create Programmable
Ground Pins" option. If this option is selected in addition to tying the unused
pins to ground, it will be more beneficial as far as noise and ground bounce
issues are concerned.
End of Record #1536 - Last Modified: 12/20/99 13:03 |
