AR# 1195: Xchecker Cable: What is the CCLK circuitry in the Xchecker cable?
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: