Micro Crystal
Ultra Small Real-Time Clock Module with SPI-Bus Interface
RV-8063-C7
October 2018
10/58
Rev. 1.1
3. REGISTER ORGANIZATION
Registers are accessed by selecting a register address and then performing read or write operations. Multiple
reads or writes may be executed in a single access, with the address automatically incrementing after each byte.
18 registers (00h
– 11h) are available. The time registers are encoded in the Binary Coded Decimal format (BCD)
to simplify application use. Other registers are either bit-wise or standard binary format. When one of the RTC
registers is written or read, the contents of all time counters are frozen for up to 1 second. Therefore, faulty writing
or reading of the clock and calendar during a carry condition is prevented.
REGISTER OVERVIEW
3.1.
After reset, all registers are set according to
Table in section REGISTER RESET VALUES SUMMARY.
Address
Function
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
00h
Control1
TEST
SR
STOP
SR
CIE
12_24
CAP
01h
Control2
AIE
AF
MI
HMI
TF
FD
02h
Offset
MODE
OFFSET
03h
RAM
RAM data
04h
Seconds
OS
40
20
10
8
4
2
1
05h
Minutes
X
40
20
10
8
4
2
1
06h
Hours (24 hour)
X
X
20
10
8
4
2
1
Hours (12 hour)
AMPM
10
8
4
2
1
07h
Date
X
X
20
10
8
4
2
1
08h
Weekday
X
X
X
X
X
4
2
1
09h
Month
X
X
X
10
8
4
2
1
0Ah
Year
80
40
20
10
8
4
2
1
0Bh
Seconds Alarm
AE_S
40
20
10
8
4
2
1
0Ch
Minutes Alarm
AE_M
40
20
10
8
4
2
1
0Dh
Hours Alarm (24h)
AE_H
X
20
10
8
4
2
1
Hours Alarm (12h)
AMPM
10
8
4
2
1
0Eh
Date Alarm
AE_D
X
20
10
8
4
2
1
0Fh
Weekday Alarm
AE_W
X
X
X
X
4
2
1
10h
Timer Value
128
64
32
16
8
4
2
1
11h
Timer Mode
X
X
X
TD
TE
TIE
TI_TP
Bit positions labeled as X are not implemented and will return a 0 when read.
