TRANSPUTER@isnet.inmos.COM (11/16/89)
Link buffering -------------- The idea behind the different link speeds on Transputers was that 20Mbits was for use unbuffered on the same board between Transputers. 10Mbit was for use if you needed to buffer it between boards and systems. 5Mbit was for the long haul. The reason the skew decreases steeper than the clock period is that there is a fixed uncertainty due to the PLL stability that needs to be subtracted from the sampling clock period. The sampling clock for 20Mbit links runs at 100MHz. Over the 11 bit period of a data packet, it must still be sampling within the data bit. If the edge of the data bit has moved due to skew the sampling clock may fall off the end, causing erroneous data to be read. Andy Rabagliati - INMOS US Central Applications EMAIL: transputer@isnet.inmos.com