Hardware Reference
In-Depth Information
Table 4-1.
DS1307 Register Map
Format
Address
Register
7
6
5
4
3
2
1
0
0x00
Seconds
CH
10s
1s
0x01
Minutes
0
10s
1s
0x02
Hours
0
24hr
10s
1s
12hr
PM
10s
1s
0x03
Weekday
0
0
0
0
0
1s
0x04
Day
0
0
10s
1s
0x05
Month
0
0
0
10s
1s
0x06
Year
10s
1s
0x07
Control
OUT
0
0
SQWE
0
0
RS1
RS2
0x08
RAM 00
byte
…
…
0x3F
RAM 55
byte
The components of the register map are further described in Table
4-2
. Bit CH allows
the host to disable the oscillator and thus stop the clock. This also disables the SQW/OUT
waveform output (when
SQWE=1
). Bit 6 of the Hours register determines whether 12- or
24-hour format is used. When in 12-hour format, bit 5 becomes an AM/PM indicator.
Table 4-2.
RTC Register Map Components
Bit
Meaning
CH
0
Clock running
1
Clock (osc) halt
24hr
0
24-hour format
12hr
1
12-hour format
RS1
RS0
Meaning
OUT
0
SQW/OUT = Low
0
0
1 Hz
1
SQW/OUT = High
0
1
4.096 kHz
SQWE
0
SQW/OUT is OUT
1
0
8.192 kHz
1
SQW/OUT is SQW
1
1
32.768 kHz
