Freescale Semiconductor MPC5200B - Manual (Page 226)

Real-Time Clock
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 7-67
7.6.3.1 RTC Time Set Register—MBAR + 0x0800
• RTC New Year and Stopwatch Register (0x0808) • RTC Periodic Interrupt and Bus Error Register (0x081C) ,
read-only
• RTC Alarm and Interrupt Enable Register (0x080C) • RTC Test Register/Divides Register (0x0820)
• RTC Current Time Register (0x0810) , read-only
Table 7-56. RTC Time Set Register
msb 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
R Reserved
set_tim
e
pa
use_t
ime
Reserved
SlctH
our
C24Hour_set
W
RESET: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 lsb
R Reserved Minute_set Reserved Second_set
W
RESET: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bits Name Description
0:5 — Reserved
6 set_time A bit used in conjunction with pause_time bit (below) to cause a new time to be programmed
into the RTC. After a proper software sequence, the values in the *_set fields below are
loaded.
The proper software sequence is:
1. Write register with pause_time 1 and set_time 0
2. Write register with pause_time 1 and set_time 1
3. Write register with pause_time 1 and set_time 0
4. Write register with pause_time 0 and set_time 0
At completion of Step 4, RTC is updated with the new time.
The C24Hour_set, Minute_set, and the Second_set fields should remain consistent values
throughout the four steps (i.e., at the desired new time values).
Note: Read-modify-write operations may disrupt this procedure, it is advised that four
simple writes occur. Byte writes to this byte are also acceptable.
7 pause_time Used with set_time above to perform time update. Must be zero for normal operation.
8:9 — Reserved
10 SlctHour This bit determines the hour output format.
• low bit = 24-hour format
• high bit = 12-hour format with AM/PM
Note: This bit does NOT affect time set procedure, it only affects how the Hour Status field
is presented.
11:15 C24Hour_set Hour in 24-hour format written in RTC after successful state machine transition by set_time
and pause_time bits.
Note: This field is always written with 24-Hour format, it is NOT affected by SlctHour bit
above.
16:17 — Reserved