DocID027266 Rev 2

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Internal RC oscillator calibration

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When running the calibration process for the MSI oscillator, the number of steps is equal to

LSE value / Input capture prescaler = 32768/8 = 4096 Hz) and the selected number of

measured periods is 10, the calibration consumes approximately:

duration = (2 x 11 x 256) / 4096 = 1.4 s

The duration of the calibration process with a maximum allowed error is lower than or equal

to the duration of calibration when using the minimum frequency error process.

Note:

Multiplying by 2 in the duration formula above is due to the fact that there is no

synchronization between the reference signal and the start of counting by the timer.