Datasheet

DocID12615 Rev 8 23/56
M41T93 Clock operation
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the digital calibration circuitry uses periodic counter correction which occurs downstream of
the 512 Hz divider chain and hence has no effect on the FT pin.
Note: 1 The modified pulses are not observable on the frequency test (FT) output, nor will the effect
of the calibration be measurable real-time, due to the periodic nature of the error
compensation.
2 Positive digital calibration is performed on an eight minute cycle, therefore the value in the
calibration register should not be modified more frequently than once every eight minutes
for positive values of calibration. Negative digital calibration is performed on a sixteen
minute cycle, therefore negative values in the calibration register should not be modified
more frequently than once every sixteen minutes.