Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

303

SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

 RTC_MR

0x400E1464

 Read

/Write 

This register can only be written if the WPEN bit is cleared in the System Controller Write Protection Mode Register 

(SYSC_WPMR).

0: 24-hour mode is selected.
1: 12-hour mode is selected.

0: Gregorian calendar.
1: Persian calendar.

0: Positive correction (the divider will be slightly lower than 32768).
1: Negative correction (the divider will be slightly higher than 32768).
Refer to CORRECTION and HIGHPPM field descriptions.

0: No correction
1..127 = The slow clock will be corrected according to the formula given below in HIGHPPM description.

0: Lower range ppm correction with accurate correction.
1: Higher range ppm correction with accurate correction.
If the absolute value of the correction to be applied is lower than 30 ppm, it is recommended to clear HIGHPPM. HIGHPPM 

set to 1 is recommended for 30 ppm correction and above.

Formula:

If HIGHPPM = 0, then the clock frequency correction range is from 1.5 ppm up to 98 ppm. The RTC accuracy is less
than 1 ppm for a range correction from 1.5 ppm up to 30 ppm..

The correction field must be programmed according to the required correction in ppm; the formula is as follows:

 

31

30

29

28

27

26

25

24

–

–

TPERIOD

–

THIGH

23

22

21

20

19

18

17

16

–

OUT1

–

OUT0

15

14

13

12

11

10

9

8

HIGHPPM

CORRECTION

7

6

5

4

3

2

1

0

–

–

–

NEGPPM

–

–

PERSIAN

HRMOD

3906

20

×

-----------------------

1

–

=