Snoop detection on calibrated bus

Abstract

An electronic system having a high speed signaling bus requiring training (calibration) of a calibrated item in a driver circuitry or a receiver circuitry for reliable operation. At manufacturing or in a secure location, secure calibration coefficients are determined for the electronic system and are stored in a non-volatile storage. During operation, the high speed signaling bus may be re-calibrated, resulting in a new currently active calibration coefficient for the calibrated item. A coefficient watchdog checks a new coefficient value selected by the re-calibration at present environmental conditions such as voltage and temperature against the secure calibration coefficients. If the new calibration coefficient value is the same as a calibration coefficient value in an acceptably close secure calibration coefficient, the new calibration coefficient is accepted; if not, a potentially probed warning is created by the coefficient watchdog.