Actually, the key is to be sure that the A/D clock source is RC. This will allow the A/D interrupt to wake up the part when conversion is complete. If the A/D clock source is Fosc/n, the A/D will stop when sleeping and not wake up. Also, if the GIE bit is disabled when the A/D conversion starts, the part will continue with program execution after the sleep instruction as opposed to vectoring to the interrupt routine if GIE is enabled. Rgds, Brian. ______________________________ Reply Separator _________________________________ Subject: Reply to A/D Sleep Mode Author: pic microcontroller discussion list at internet Date: 8/22/95 9:51 AM Norman, When the PIC16C74 is in sleep mode, OSC1 is disabled (therefore the internal clock). To wake up the processor, there must be a WDT timeout, or an external event must be provided (either a change on portb or a clock to the other peripherals, etc.). The A/D interrupt will not wake up the processor. If your were trying to use the A/D interrupt to wake up the processor, hopefully this will shine some light on the situation. ------------------------------------------------------------ Rod DeMay | B&B Electronics Mfg. Co. | email - rdemay@bb-elec.com 707 Dayton Rd | phone - (815) 433-5100 x220 PO Box 1040 | fax - (815) 434-7094 Ottawa, IL 61350 | ------------------------------------------------------------ =1A