External device power control during low power sleep mode without central processing intervention

摘要

The integrated circuit device controls the power-up of the external device used to sense the process variable regardless of whether the integrated circuit device is in the low-power sleep mode. When the external device is operated, it samples the process variable state of the external device even when the integrated circuit device is still in the low-power sleep mode. The low-power timing circuits operating during the low-power sleep mode control the power-up of the external device and the sampling of the process variable state. After the sample of the process variable state is performed, the integrated circuit device may return the low power sleep mode to the operating mode if determined to be necessary from the sampled process variable state.