I'm working on a design for a battery-powered, AVR-based clock. It's my first battery-powered project so I'm drilling down into power consumption more than I usually do. My understanding was that different clocking approaches can effect power consumption (e.g. using an external oscillator causes the MCU to draw more current than using a crystal and the MCU's oscillator), though I can't track down evidence for that belief at the moment, so any pointers for that issue would be appreciated. I didn't try especially hard, though, because that's not my main question. What I'd really like to know is if a crystal itself draws power that needs to be added to the power budget, or if its consumption is rolled into the MCU's power consumption number. The few crystal datasheets I've perused don't provide any power info, leading me to believe I can ignore it, but it seems a little counterintuitive, so I decided to check here. Thanks for your help.
Joined: Tue. Apr 1, 2003
Posts: 480 View posts