Apart from Format binary, Timer 1 has two other formats [Hr:min:sec:hundreds (23hrs to 0) and Hr:min:sec:hundreds (255hrs to 0)].
Can you give a more detailed description of these formats, answering the following questions:-
1. 23hours to 0. Why 23hrs and not 24hrs?
2. Can Format '10' count up and roll over like a real clock?
3. If the external 32.768KHz oscillator is used then it makes sense to use the 1/32768 prescaler. This gives a tick granularity of 1sec, so what happens to the hundreds field?
5. Can you provide correct settings and code to allow one of these formats to be used as an accurate clock, when using the 32.768KHz external oscillator?