DS17285E3 MAXIM [Maxim Integrated Products], DS17285E3 Datasheet - Page 14

• Manufacturer Part Number: DS17285E3
• Description: Real-Time Clocks
• Manufacturer: MAXIM [Maxim Integrated Products]

The four control registers (A, B, C, and D) reside in
Real-Time Clocks
Bit 7: Update In Progress (UIP). This bit is a status
flag that can be monitored. When the UIP bit is 1, the
update transfer will soon occur. When UIP is 0, the
update transfer does not occur for at least 244µs. The
time, calendar, and alarm information in RAM is fully
available for access when the UIP bit is 0. The UIP bit is
read-only. Writing the SET bit in Register B to 1 inhibits
any update transfer and clears the UIP status bit.
Table 3B. Time, Calendar, and Alarm Data Modes—Binary Mode (DM = 1)
Note: Unless otherwise specified, the state of the registers is not defined when power is first applied. Except for the seconds regis-
ter, 0 bits in the time and date registers can be written to 1, but can be modified when the clock updates. 0 bits should always be
written to 0 except for alarm mask bits.
Register A (0Ah)
MSB
14
Bank 1, 48h
Bank 1, 49h
ADDRESS
BIT 7
0Ah
0Bh
0Ch
0Dh
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
UIP
____________________________________________________________________
AM/PM
AM/PM
BIT 7
IRQF
VRT
SET
UIP
0
0
0
0
0
0
0
0
0
0
BIT 6
DV2
BIT 6
DV2
10 Century
PIE
PF
Control Registers
0
0
0
0
0
0
0
0
0
0
10 Date
BIT 5
DV1
BIT 5
DV1
AIE
AF
0
0
0
0
0
0
BIT 4
DV0
UIE
UF
0
0
0
0
0
BIT 4
DV0
SQWE
BIT 3
Year
RS3
0
0
0
Seconds
Seconds
Minutes
Minutes
Hours
Hours
BIT 2
Date
RS2
DM
both bank 0 and bank 1. These registers are accessi-
ble at all times, even during the update cycle.
Bits 6, 5, and 4: DV2, DV1, and DV0. These bits are
used to turn the oscillator on or off and to reset the
countdown chain. A pattern of 01X is the only combina-
tion of bits that turns the oscillator on and allows the RTC
to keep time. A pattern of 11X enables the oscillator but
holds the countdown chain in reset. The next update
occurs at 500ms after a pattern of 01X is written to DV0,
DV1, and DV2. DV0 is used to select bank 0 or bank 1 as
defined in Table 5. When DV0 is set to 0, bank 0 is
selected. When DV0 is set to 1, bank 1 is selected.
0
0
Century
BIT 3
Month
Hours
Hours
RS3
Date
BIT 1
24/12
Day
RS1
0
0
BIT 0
RS0
DSE
0
0
BIT 2
RS2
Seconds Alarm
Minutes Alarm
Hours Alarm
FUNCTION
Date Alarm
Seconds
Minutes
Century
Control
Control
Control
Control
Month
Hours
Date
Year
Day
BIT 1
RS1
1–0C +AM/PM
1–0C +AM/PM
RANGE
01–0C
00–3B
00–3B
00–3B
00–3B
00–17
00–17
01–07
01–1F
00–63
00–63
01–1F
—
—
—
—
BIT 0
RS0
LSB