Shock absorber having variable damping characteristics. coli O157:H7 colonization and shedding in ruminant animals. A sensor system may be provided with integrated signal processing electronics, for monitoring a change in differential channel current ID, indicative of radiation dose, and an integrated negative bias generator for automatic pre-charging from a low voltage power source. When a user wishes to revert a configuration setting back to a previous one, the user can select the desired setting for reversion and a call to a reversion routine can be made. In a method for operating a microcontroller as described above, the method includes the step of debugging or programming the microcontroller using only a single signal pin of the external pins.