In message <0000B8B7.1655@plantronics.com>, Scott Walsh writes > I think Steve has probably identified your problem. > > You may have overlooked this parameter when specifiying the crystal > that you are using, this is easy to do as it is not an intuitive thing > to check for! > > AFAIK they call a third overtone XTAL an 'XT cut' and a fundamental > mode XTAl an 'AT cut' ... anybody know what this is? > It refers to the direction the crystal is cut relative to its axes, and determines the way the crystal vibrates. AT-cut crystals are cut from the crystal bar at an angle of approx. 35 degrees, according to the IQD Crystal Product Data Book I've got. I don't know where the terms come from. Leon -- Leon Heller: leon@lfheller.demon.co.uk http://www.lfheller.demon.co.uk Amateur Radio Callsign G1HSM Tel: +44 (0) 118 947 1424 See http://www.lfheller.demon.co.uk/rcm.htm for details of a low-cost reconfigurable computing module using the XC6216 FPGA