The 32.768 crystal would be a bit more handy than a 12mHz or 16mHz one, but I could not find one in a proper package for my pcb. In addition to this, the low frequency crystals needs to be connected on different pin on the pic which, again causes some problems.
My understanding is that if I use a 16mHz crystal, the only problem is that I will need to set prescaler to 8, have an interrupt every 50.000 cycles (16 bits timer), and increment the seconds every twentieth call of the interrupt. With a 32.768kHz crystal I could just have the interrupt called every 32.768 ticks.
I am right there ? And if I am, can I use this 16mHz crystal for my pic ?
Thank you,
John.