I've been having slow startup problems with my 12F629 and 12F683 32.768hz crystal clocked pics. I used the crystal recommended in the Midrange Reference Manual DS33023A (Epson C-001R32.768K) and from the recommend capacitors range (68-100pf) I started with 68pf. It takes several seconds for the oscillator to stabilize. I tried the hign end of the range, and it never starts with a 100pf cap. So reading the Basic PicMicro Oscillator Design document AN849, it indicates to use a 33pf cap, which works much better. In fact I've found it works with caps down to 5pf.
While AN849 is probably the definitive document on this stuff, I found it hard to apply in practice with my limited equipment and experience. I'm curious to know what others have found to be the best value to use with similar setups at 32Khz.
While AN849 is probably the definitive document on this stuff, I found it hard to apply in practice with my limited equipment and experience. I'm curious to know what others have found to be the best value to use with similar setups at 32Khz.