[time-nuts] Maxim DS1342

[Dan Kemppainen]

The microchip pics on the bench here actually have the oscillators in
them for the 32Khz xtal. That is, the gain and feedback to make the
crystal run are in them. All that is needed is some capacitance to
ground. This is why the SOSC (Secondary Oscillator) uses two pins. You
can also use a single input to trigger the counters. With correct RTC
routines, in software you should have no problem running a clock from a
single PPS.


Really, other than a programmer and some code required, An RTC in a low
power micro, that can 'wake up' and do things at multiple 10's of Mhz
for periods of time seems much more flexible than a single RTC.
Especially when the micro is drawing only uA when acting as an RTC...


Dan



On 11/12/2013 12:37 AM, time-nuts-request at febo.com wrote:
> russ.ramirez at gmail.com said:
>> > Looking across the TI and Microchip lines a bit, it strikes me as odd that
>> > more micros supporting integrated RTCs actually use two I/Os for a 32 kHz
>> > crystal option. Why they support an RTC is not mysterious at all, but why
>> > not the option at to drive the 1 Hz clock directly rather than dividing 32
>> > kHz down to 1 Hz and using an extra I/O is odd when these I/Os are usually
>> > configurable anyway.