This anomaly applies to IC Rev. Engineering B, build codes QFAA-BA0, CHAA-AA0.
The LFCLK RC oscillator frequency can have a frequency error of up to -25 to +40% after reset. A +/- 2% error is stated in the Product Specification.
Always
The LFCLK RC oscillator frequency is inaccurate.
Calibrate the LFCLK RC oscillator before its first use after a reset.