M48T212V-85MH1TR(2000) View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
M48T212V-85MH1TR Datasheet PDF : 23 Pages
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M48T212Y, M48T212V
Table 13. TIMEKEEPER Register Map
Address
Fh
Eh
Dh
Ch
Bh
Ah
9h
8h
7h
6h
5h
4h
3h
2h
1h
0h
D7
0
0
0
0
0
ST
W
WDS
AFE
RPT4
RPT3
RPT2
RPT1
WDF
D6
D5
D4
10 Years
0
0
10M
0
10 Date
FT
0
0
0
10 Hours
10 Minutes
10 Seconds
R
S
BMB4 BMB3 BMB2
0
ABE Al 10M
RPT5
AI 10 Date
0
AI 10 Hour
Alarm 10 Minutes
Alarm 10 Seconds
1000 Year
AF
Y
BL
D3
D2
D1
D0
Year
Month
Date: Day of Month
0
Day of Week
Hours (24 Hour Format)
Minutes
Seconds
Calibration
BMB1 BMB0 RB1
RB0
Alarm Month
Alarm Date
Alarm Hour
Alarm Minutes
Alarm Seconds
100 Year
Y
Y
Y
Y
Fu nctio n/Range
BCD Format
Year
Month
Date
Day
Hour
Min
Sec
Control
Watchdog
A Month
A Date
A Hour
A Min
A Sec
Century
Flag
00-99
01-12
01-31
01-7
00-23
00-59
00-59
01-12
01-31
00-23
00-59
00-59
00-99
Keys:
S = Sign Bit
FT = Frequency Test Bit
R = Read Bit
W = Write Bit
ST = Stop Bit
0 = Must be set to zero
BL = Battery Low Flag
BMB0-BMB4 = Watchdog Multiplier Bits
AFE = Alarm Flag Enable Flag
RB0-RB1 = Watchdog Resolution Bits
WDS = Watchdog Steering Bit
ABE = Alarm in Battery Back-Up Mode Enable Bit
RPT1-RPT5 = Alarm Repeat Mode Bits
WDF = Watchdog flag
AF = Alarm flag
Y = ‘1’ or ‘0’
VCC SWITCH OUTPUT
Vccsw output goes low when VOUT switches to
VCC turning on a customer supplied P-Channel
MOSFET (see Figure 3). The Motorola
MTD20P06HDL is recommended. This MOSFET
in turn connects VOUT to a separate supply when
the current requirement is greater than IOUT1 (see
Tables 7A and 7B). This output may also be used
simply to indicate the status of the internal battery
switchover comparator, which controls the source
(VCC or battery) of the VOUT output.
POWER-ON RESET
The M48T212Y/V continuously monitors VCC.
When VCC falls to the power fail detect trip point,
the RST pulls low (open drain) and remains low on
power-up for 40 to 200ms after VCC passes VPFD.
The RST pin is an open drain output and an appro-
priate pull-up resistor to VCC should be chosen to
control rise time.
Note: If the RST output is fed back into either of
the RSTIN inputs (for a microprocessor with a bi-
directional reset) then a 1kΩ (max) pull-up resistor
is recommended.
Reset Inputs (RSTIN1 & RSTIN2)
The M48T212Y/V provides two independent in-
puts which can generate an output reset. The du-
ration and function of these resets is identical to a
reset generated by a power cycle. Table 14 and
Figure 12 illustrate the AC reset characteristics of
this function. During the time RST is enabled
(tR1HRH & tR2HRH), the Reset Inputs are ignored.
Note: RSTIN1 and RSTIN2 are each internally
pulled up to VCC through a 100KΩ resistor.
15/23
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