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AR# 1301

XC5200 - Programmable keeper cells are automatically enabled when all buffers are in a 3-state condition


Keywords: keeper, cells, 3-state, tristate

Urgency: Standard

General Description:
In "The Programmable Logic Data Book" (7/96 and 9/96) on page 4-194, in paragraph 2 of column 2, it states:

"Additionally, programmable keeper cells at the periphery can be enabled to retain the last valid logic level on the long
lines when all buffers are in 3-state mode."

Is this correct?


This passage can be confusing. The "programmable keeper cells" mentioned in the text are said to be "enabled", which can lead you to believe that you must turn on a switch in the software to activate these cells. This is not the case. Instead, these "programmable keeper cells" are automatically enabled by the software whenever all buffers are in a 3-state condition.
AR# 1301
Date Created 08/31/2007
Last Updated 02/27/2003
Status Archive