STMicroelectronics /STM32U083 /RTC /RTC_CALR

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Interpret as RTC_CALR

CALP=B_0x0, LPCAL=B_0x0

Description

RTC calibration register

Fields

CALM	Calibration minus The frequency of the calendar is reduced by masking CALM out of 2²⁰ RTCCLK pulses (321seconds if the input frequency is 327681Hz). This decreases the frequency of the calendar with a resolution of 0.95371ppm. To increase the frequency of the calendar, this feature should be used in conjunction with CALP. See Section128.3.14: RTC smooth digital calibration on page1733.
LPCAL	RTC low-power mode 0 (B_0x0): Calibration window is 2²⁰ RTCCLK, which is a high-consumption mode. This mode must be set only when less than 32s calibration window is required. 1 (B_0x1): Calibration window is 2²⁰ ck_apre, which is the required configuration for ultra-low consumption mode.
CALW16	Use a 16-second calibration cycle period When CALW16 is set to 1, the 16-second calibration cycle period is selected. This bit must not be set to 1 if CALW8 = 1. Note: CALM[0] is stuck at 0 when CALW16 = 1. Refer to Section128.3.14: RTC smooth digital calibration.
CALW8	Use an 8-second calibration cycle period When CALW8 is set to 1, the 8-second calibration cycle period is selected. Note: CALM[1:0] are stuck at 00 when CALW8 = 1. Refer to Section128.3.14: RTC smooth digital calibration.
CALP	Increase frequency of RTC by 488.51ppm. 0 (B_0x0): No RTCCLK pulses are added. 1 (B_0x1): One RTCCLK pulse is effectively inserted every 2¹¹ pulses (frequency increased by 488.51ppm).

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