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AR# 1195

Xchecker Cable: What is the CCLK circuitry in the Xchecker cable?

Description

When interfacing the xchecker cable to a custom PC board, it is sometimes important to know the CCLK circuitry.

Solution

The CCLK pin is driven by an IOB on the XC3042 inside XChecker.
It has the same sink/source characteristics as listed in the
3000 datasheets. The pin is terminated with 100 ohm, 100pF network as shown below:

--------
| 100
|-------+------\/\/\/-----O CCLK to user's
XC3042 | | Board
| --- 100pF
-------- ---
|
|
GND

AR# 1195
Date 10/01/2008
Status Archive
Type General Article