This anomaly applies to Revision 3, build codes QFAA-Gx0, QFAB-Gx0, CIAA-Gx0.
It was inherited from the previous SoC revision Revision 2.
Symptoms
LFRC oscillator frequency is wrong after calibration, exceeding 500 ppm.
Conditions
On some devices, when entering System ON Idle while calibration is ongoing.
Consequences
After calibration, LFRC has a frequency offset that is outside specification.
Workaround
Apply the following code before starting the RCOSC32K calibration:
*(volatile uint32_t *)0x40000C34 = 0x00000002;
*(volatile uint32_t *)0x40000C34 = 0x00000000;