HANBit
HMNR1288D(V)
CLOCK OPERATIONS
The HMNR1288D(V) offers 16 internal registers which contain TIMEKEEPER, and Control data. These registers are
memory locations which contain external (user accessible) and internal copies of the data. The external copies are
independent of internal functions except that they are updated periodically by the simultaneous transfer of the incremented
internal copy. TIMEKEEPER Registers store data in BCD. Control Registers store data in Binary Format.
Setting the Alarm Clock
Registers 1FFF6h-1FFF2h contain the alarm settings. The alarm can be configured to go off at a prescribed time on a
specific month, date, hour, minute, or second or repeat every month, day, hour, minute, or second. It can also be
programmed to go off while the HMNR1288D(V) is in the battery back-up to serve as a system wake-up call. Bits RPT5-
RPT1 put the alarm in the repeat mode of operation. Table 12, page 19 shows the possible configurations. Codes not
listed in the table default to the once per second mode to quickly alert the user of an incorrect alarm setting.
Note: User must transition address (or toggle Chip Enable) to see Flag Bit change.
When the clock information matches the alarm clock settings based on the match criteria defined by RPT5-RPT1, the AF
(Alarm Flag) is set. If AFE (Alarm Flag Enable) is also set, the alarm condition activates the IRQ/FT pin. To disable alarm,
write ’0’ to the Alarm Date register and RPT1-5. The IRQ/FT output is cleared by a READ to the Flags Register as shown
in Figure 6. A subsequent READ of the Flags Register is necessary to see that the value of the Alarm Flag has been reset
to ’0.’
The IRQ/FT pin can also be activated in the battery back-up mode. The IRQ/FT will go low if an alarm occurs and both
ABE (Alarm in Battery Back-up Mode Enable) and AFE are set. The ABE and AFE Bits are reset during power-up,
therefore an alarm generated during power-up will only set AF. The user can read the Flag Register at system boot-up to
determine if an alarm was generated while the HMNR1288D(V) was in the deselect mode during power-up. Figure 7,
illustrates the back-up mode alarm timing.
Figure 6. Alarm Interrupt Reset Waveform
Alarm Repeat Mode
RPT5
Alarm Activated
RPT4
1
RPT3
1
RPT2
1
RPT1
1
1
1
1
1
1
0
Once per Second
Once per Minute
Once per Hour
Once per Day
1
1
1
0
0
1
1
0
0
0
1
0
0
0
0
0
0
0
0
0
Once per Month
Once per Year
URL : www.hbe.co.kr
Rev. 1.0 (April, 2002)
11
HANBit Electronics Co.,Ltd
HANBIT [ HANBIT ELECTRONICS CO.,LTD ]
