I'm working with an LPC2387 (datasheet), and pp. 55-56 of the datasheet specifies several options for the RTC crystal with different load capacitance: 11pf, 13pf, and 15pf. For each of these crystals, different load capacitors are specified.
First, the datasheet speaks exclusively of "32 KHz" crystals. It seems to me that what they really mean is "32.768 KHz", is that correct?
Second, these load capacitances seem odd to me, since neither Digi-Key nor Mouser carry 32KHz crystals with these specifications. There is a 12.5pf crystal, which is possibly close enough, but not exact. Am I expected to calculate the capacitance of my traces and factor that into my choice, or do I simply choose the closest match?
Third, if I do end up having a choice of crystals, should I choose the highest load capacitance? Does that provide a more stable oscillation?