Register B
Register B enables:
n
Updatecycletransfer operation
n
Interrupt events
n
Daylight saving adjustment
Register B selects:
n
Clock and calendar data formats
All bits of register B areread/write.
Bit 3 - Unused Bit.
DSE - Daylight Saving Enable
This bit enables daylight-saving time adjustments when
written to1:
n
On the last Sunday in October, the first time the
bq3285EC/LC increments past 1:59:59 AM, the time
falls back to1:00:00 AM.
n
On the first Sunday in April, the time springs
forward from 2:00:00 AM to3:00:00 AM.
HF - Hour Format
This bit selects thetime-of-day and alarm hour format:
1 = 24-hour format
0 = 12-hour format
DF - Data Format
This bit selects the numeric format in which the time,
alarm, and calendar bytes arerepresented:
1 = Binary
0 = BCD
UIE - Update Cycle Interrupt Enable
This bit enables an interrupt request due to an update
ended interrupt event:
1 = Enabled
0 = Disabled
The UIE bit is automatically cleared when the UTI bit
equals 1.
AIE - Alarm Interrupt Enable
This bit enables an interrupt request due to an alarm
interrupt event:
1 = Enabled
0 = Disabled
PIE - Periodic Interrupt Enable
This bit enables an interrupt request due to a periodic
interrupt event:
1 = Enabled
0 = Disabled
UTI - Update Transfer Inhibit
This bit inhibits the transfer of RTC bytes to the user
buffer:
1 = Inhibits transfer and clears UIE
0 = Allows transfer
9
bq3285EC/LC
7
-
6
-
5
-
4
-
3
-
2
-
1
-
0
DSE
7
-
6
-
5
-
4
-
3
-
2
-
1
0
-
HF
7
-
6
-
5
-
4
-
3
-
2
1
-
0
-
DF
7
-
6
-
5
-
4
3
-
2
-
1
-
0
-
UIE
Register B Bits
4
UIE
7
6
5
3
-
2
1
0
UTI
PIE
AIE
DF
HF
DSE
7
-
6
-
5
4
-
3
-
2
-
1
-
0
-
AIE
7
-
6
5
-
4
-
3
-
2
-
1
-
0
-
PIE
July 1996
7
6
-
5
-
4
-
3
-
2
-
1
-
0
-
UTI