AR# 1195: Xchecker Cable: What is the CCLK circuitry in the Xchecker cable?
Xchecker Cable: What is the CCLK circuitry in the Xchecker cable?
When interfacing the xchecker cable to a custom PC board, it is sometimes important to know the CCLK circuitry.
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: