In certain applications, the PIC16CXXX is exercised only when a key is pressed, (e.g., remote keyless entry). In such applications, the battery life can be extended by putting the PIC16CXXX to sleep during inactive states and when a key is pressed, the PIC16CXXX wakes up, performs the task, and then goes back to sleep. AN528 Implementing Wake-up on Key Stroke are both set to a low logic level. In this state, the capac- Author: Stan D’Souza itor C is fully charged and a high logic level is present at Microchip Technology Inc. the MCLR pin. When a key is pressed, C discharges through either R2 or R3 (depending on which switch is being pressed). The voltage across C falls rapidly INTRODUCTION ……