Electronics notes
2008-07-22 23:41:21.152131+02 by Dan Lyke 0 comments
I'm prototyping a bike computer using an Atmel ATmega16 with the 32kHz clock crystal, and yesterday I was having some really wacky situations where it appeared that sometimes the crystal just wasn't starting. My little development board breaks out all of the pins to standard headers that the STK-500 uses. TOSC1 and TOSC2, the pins which drive the crystal, are shared with pins 6 and 7 of PORTC, so I had the little through holes on the board to solder in the crystal, and then continued the traces through to the connector for PORTC.
This morning I decided to cut the continuation of those traces, and now the board works wonderfully. This is a note to anyone dealing with such issues in the future: Half an inch of empty board trace can keep even a slow crystal like that from starting. My next proto board design is going to be even more compact than the 2"x2½" of the current one.