Answers Database
2.1i CPLD: How to use programmable grounds for unused pins in 9500/XL devices
Record #3404
Problem Title:
2.1i CPLD: How to use programmable grounds for unused pins in 9500/XL devices
Problem Description:
Urgency: Standard
What happens to unused pins in 9500/XL designs?
Do I have to tie them to ground on the board?
Solution 1:
Unused pins in 9500 devices are left floating unless you check the option
"create programmable ground pins" in the fitter options*. Selecting this
option tells the fitter to tie unused pins to ground internally so you will
not have to tie these pins to ground on your board.
Tying unused IO to ground either on the board or via software is
recommended as it reduces noise and power consumption from floating signals.
*In the Foundation Project Manager, the options are located under
Implementation->Options then select the User Defined radio button,
then click on Edit Options and choose the Basic tab.
Solution 2:
For the Solaris CPLD program:
To invoke the User Programmable Grounds use the '-grounds' option.
End of Record #3404 - Last Modified: 02/07/00 10:01 |
