MPC5200B Users Guide, Rev. 1
7-70 Freescale Semiconductor
Real-Time Clock
7.6.3.5 RTC Current Time Register—MBAR + 0x0810
This is a read-only register.
8:10 — Reserved
11:15 Alm_24Hset Hour setting (in 24 hour format) to be compared to time of day for the purpose of generating
Alarm Status/Interrupt. Can be written at any time.
16:17 — Reserved
18:23 Alm_Min _set Minute setting to be compared to time of day for the purpose of generating Alarm
Status/Interrupt. Can be written at any time.
24:27 — Reserved
28 MPEb Master Periodic Enable bar. Must be written low after reset to allow periodic interrupts.
29 IntEn_day Enable bit of periodic interrupts at midnight rollover.
30 IntEn_min Enable bit of periodic interrupts at minute rollover.
31 IntEn_sec Enable bit of periodic interrupts at second rollover.
Note: The Interrupt enable bits (28, 29, 30, 31) control the Periodic Interrupt coming from the RTC. The separate
Stopwatch/Alarm Interrupt signal does not have a specific interrupt enable bit. An Alarm interrupt is automatically
generated if Alarm is enabled and the Alarm setting matches time of day. Similarly, a Stopwatch expiration, which
shares the Alarm interrupt signal, automatically occurs once the Stopwatch is initiated and the Stopwatch counter
expires.

Table7-60. RTC Current Time Register

msb 012345678 9 101112131415
RReserved Hour
W
RESET:000000000 0 0 000 0 0
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 lsb
RReserved Minute Reserved Second
W
RESET:000000000 0 0 000 0 0
Bits Name Description
0:10 — Reserved
11:15 Hour Hour format can be either 24-hour or 12-hour with AM /PM.
If 24-hour format is selected (SlctHour low in Reg 0), the whole 5-bit hour field designates
current time in 24-hour format.
If 12-hour format is selected (SlctHour high in Reg 0), the MSB of hour field indicates:
Hour[0 ]=0 : AM,
Hour[ 0]= 1: PM and
Hour[ 1:4] designates current ti me in 12-hour format.
16:17 — Reserved
18:23 Minute Shows minutes in current time.
Bits Name Description