I am just about to order a new PCB, but before I order I would like confirmation I have wired up the micro Low Power Crystal correctly.
Using the ATmega324P I would like to use the 32kHz low power external crystal, and put the micro to sleep and wake up using an external interrupt.
Reading the Datasheet it says "The Oscillator is optimized for use with a 32.768 kHz watch crystal", however reading the forum other people mention they are using just a 32kHz watch crystal.?
So I have opted to use a 32.768 kHz watch crystal and connect to XTAL1 (with a 18pf cap) and XTAL2 (with a 8pf cap), page 35 on the datasheet. Have I read this correct?
Lastly one other question, when the micro wakes up on the interrupt, can a 100kHz I2C device be run on a 128kHz internal clock or would I have to use a something like a 1MHz clock?
Look forward to your reply.