Answers Database
CPLD: 9500* : Usage of internal pullup in IOB
Record #3026
Product Family: Hardware
Product Line: 9500
Product Part: 9500
Problem Title:
CPLD: 9500* : Usage of internal pullup in IOB
Problem Description:
Urgency: Standard
and when can the user program them?
Solution 1:
The IOB of every 9500* device has a control pull-up resistor
attached to each IO pin to prevent them from floating when
the device is not in normal operation.
The resistor becomes active during device programming and
system power-up. The resistor is also activated for an erased
device. This includes a new device and a device that has been
programmed then erased.
At all other times the resistor is de-activated. The resistor
is not available to the developer during normal operation. If
a pullup is required in the design, one will have to be added
externally.
* 9500/XL/XV
End of Record #3026 - Last Modified: 01/05/00 16:40 |
