SAM3SD8B Atmel Corporation, SAM3SD8B Datasheet - Page 254

• Manufacturer Part Number: SAM3SD8B
• Manufacturer: Atmel Corporation

14.5.2
Name:
Address:
Access:
• HRMOD: 12-/24-hour Mode
0 = 24-hour mode is selected.
1 = 12-hour mode is selected.
• PERSIAN: PERSIAN Calendar
0 = Gregorian Calendar.
1 = Persian Calendar.
• NEGPPM: NEGative PPM Correction
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.
• CORRECTION:
0 = No correction
1..127 = The slow clock will be corrected according to the formula given below in HIGHPPM description.
• HIGHPPM: HIGH PPM Correction
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 30ppm, it is recommended to clear HIGHPPM. HIGHPPM
set to 1 is recommended for 30 ppm correction and above.
254
254
HIGHPPM
Formula:
If HIGHPPM = 0, then the clock frequency correction range is from 1.5 ppm up to 98 ppm. The RTC accuracy will be
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
23
15
–
–
7
–
SAM3S8/SD8
SAM3S8/SD8
RTC Mode Register
RTC_MR
0x400E1464
Read-write
30
22
14
–
6
–
OUT1
29
21
13
5
–
TPERIOD
NEGPPM
28
20
12
4
CORRECTION
27
19
11
–
–
–
3
26
18
10
2
–
PERSIAN
THIGH
OUT0
25
17
9
1
11090A–ATARM–10-Feb-12
11090A–ATARM–10-Feb-12
HRMOD
24
16
8
0