m41t81 STMicroelectronics, m41t81 Datasheet - Page 14

• Manufacturer Part Number: m41t81
• Description: Serial Access Real-time Clock With Alarms
• Manufacturer: STMicroelectronics

Clock operation
Table 2.
1. Keys:
14/30
Addr
0Ch
0Dh
0Ah
0Bh
0Eh
0Fh
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
10h
11h
12h
13h
S = Sign Bit
FT = Frequency Test Bit
ST = Stop Bit
0 = Must be set to '0'
BMB0-BMB4 = Watchdog Multiplier Bits
CEB = Century Enable Bit
CB = Century Bit
OUT = Output level
ABE = Alarm in Battery Back-up Mode Enable Bit
AFE = Alarm Flag Enable Flag
RB0-RB1 = Watchdog Resolution Bits
RPT1-RPT5 = Alarm Repeat Mode Bits
WDF = Watchdog Flag (Read only)
AF = Alarm Flag (Read only)
SQWE = Square Wave Enable
RS0-RS3 = SQW Frequency
HT = Halt Update Bit
RPT4
RPT3
RPT2
RPT1
WDF
OUT
CEB
AFE
RS3
D7
ST
0
0
0
0
0
0
0
0
Clock register map
SQWE
BMB4
RPT5
RS2
D6
CB
HT
AF
FT
0
0
0
0
0
0
0.1 seconds
10 years
Alarm 10 seconds
Alarm 10 minutes
10 seconds
10 minutes
BMB3
ABE
RS1
D5
S
0
0
0
0
0
0
AI 10 hour
AI 10 date
10 hours
10 date
(1)
Al 10M
BMB2
10M
RS0
D4
0
0
0
0
0
BMB1
D3
0
0
0
0
0
0
Hours (24 hour format)
Calibration
Date: day of month
BMB0
Alarm seconds
Alarm minutes
0.01 seconds
D2
Alarm month
0
0
0
0
0
Alarm date
Alarm hour
Seconds
Minutes
Month
Year
Day of week
RB1
D1
0
0
0
0
0
RB0
D0
0
0
0
0
0
Watchdog
Reserved
Reserved
Reserved
Function/range BCD
Seconds
Seconds
Al month
Century/
Minutes
Control
Al date
Al hour
Month
Al min
Al sec
hours
SQW
Flags
Date
Year
Day
format
0-1/00-23
00-99
00-59
00-59
01-31
01-12
00-99
01-12
01-31
00-23
00-59
00-59
M41T81
01-7