LPCAL=B_0x0, CALP=B_0x0
RTC calibration register
| CALM | Calibration minus The frequency of the calendar is reduced by masking CALM out of 2sup20/sup RTCCLK pulses (32 seconds if the input frequency is 32768 Hz). This decreases the frequency of the calendar with a resolution of 0.9537 ppm. To increase the frequency of the calendar, this feature should be used in conjunction with CALP. See Section 31.3.15: RTC smooth digital calibration on page 1092. |
| LPCAL | RTC low-power mode 0 (B_0x0): Calibration window is 2sup20/sup 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 2sup20/sup 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 Section 31.3.15: 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 Section 31.3.15: RTC smooth digital calibration. |
| CALP | Increase frequency of RTC by 488.5 ppm This feature is intended to be used in conjunction with CALM, which lowers the frequency of the calendar with a fine resolution. Refer to Section 31.3.15: RTC smooth digital calibration. 0 (B_0x0): No RTCCLK pulses are added. 1 (B_0x1): One RTCCLK pulse is effectively inserted every 2sup11/sup pulses (frequency increased by 488.5 ppm). |