I wanted to breadboard an Arduino today and must rely on my local Maplin (eg RadioShack) for some parts. I've checked stock online and the only suitable crystal oscillator modules they have are 20Mhz. Can I use this for now just to get up and running?
They also have 4, 10, 6, 3.579 (!) MHz crystals but not in U4 style case. Would one of these be better?
It depends on if you're using anything that is timing critical (like serial or programming it on the breadboad). See if they have a 16 Mhz ceramic resonator, a better substitute than a 20 Mhz crystal. (you don't need the capacitors either). You tweak the legs a bit to fit a breadboard........
Craplins only have a 4MHz ceramic. My ATMega328 came with a bootloader burnt in already. I read a post that suggested the bootloader code hardwires the clock frequency so would I need to flash a new bootloader too?
Darn it! Maplins do a 16MHz crystal they just have none in stock!
Maplins arnt the best for range of parts but if you order a few crystals or resonators from the website it should be with you next day in a small jiffy bag. There mail order is probably there best service.
Ive ordered up to 6pm in the evening and had the parts the next day.
But the earlier in the day the better.