MCP79401T-I/SN Microchip Technology, MCP79401T-I/SN Datasheet - Page 14
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MCP79401T-I/SN
Manufacturer Part Number
MCP79401T-I/SN
Description
Real Time Clock I2C GP RTCC 64B SRAM EUI-48
Manufacturer
Microchip Technology
Series
-r
Type
Clock/Calendarr
Datasheet
1.MCP79401T-IMNY.pdf
(38 pages)
Specifications of MCP79401T-I/SN
Features
Alarm, Leap Year, SRAM, Unique ID
Memory Size
64B
Time Format
HH:MM:SS (12/24 hr)
Date Format
YY-MM-DD-dd
Interface
I²C
Voltage - Supply
1.8 V ~ 5.5 V
Voltage - Supply, Battery
1.3 V ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (0.154", 3.90mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
MCP7940X
In the case where the MSB of the Calibration register
is set to ‘1’, the MFP output waveforms that appear
when bits RS1 and RS0 are set to ‘01’ or ‘10’ are not
as responsive to the setting of the Calibration register.
For example, when outputting the 4.096 kHz
waveform (RS1, RS0 set to ‘01’), the output waveform
is generated using only eight input clock cycles.
Consequently, attempting to subtract more than eight
input clock cycles from this output does not have a
meaningful effect on the resulting waveform. Any
effect on the output will appear as a modification in
both the frequency and duty cycle of the waveform
appearing on the MFP output pin.
B.RS2 BIT SET TO ‘1’
With the RS2 bit set to ‘1’, the following internal timing
signal is output on the MFP pin:
The frequency listed in the table presumes an input
clock source of exactly 32.768 kHz. In terms of the
equivalent number of input clock cycles, the table
becomes:
Unlike
calibration setting is continuously applied and affects
every cycle of the output waveform. This results in the
modulation of the frequency of the output waveform
based upon the setting of the Calibration register.
Using this setting, the calibration function can be
expressed as:
Since the calibration is done every cycle, the frequency
of the output MFP waveform is constant.
DS25009A-page 14
where:
RS2
RS2
CALREG
1
1
T
T
T
output
output
input
the
RS1
RS1
x
x
=
=
=
=
method
(2 * (256 +/- (2 * CALREG))) T
clock period of MFP output signal
clock period of input signal
decimal value of the Calibration
register setting, and the sign is
determined by the MSB of the
Calibration register.
RS0
RS0
x
x
previously
Output Signal
Output Signal
64.0 Hz
described,
512
input
the
4.2.3
Pin 7 is a multi-function pin and supports the following
functions:
• Use of the OUT bit in the Control register for
• Alarm Outputs – Available in V
• FOUT mode – driven from a FOSC divider – Not
The internal control logic for the MFP is connected to
the switched internal supply bus, this allows operation
in V
operates in V
4.2.4
If the V
should be connected to GND. A low-value series
resistor is recommended between the external battery
and the V
The V
falls below 1.5V the system will continue to operate
the RTCC and SRAM using the V
following conditions apply:
TABLE 4-2:
4.2.5
The MCP7940X has been designed to operate with a
standard 32 kHz crystal. Devices with a specified load
capacitance of either 12pF or 6pF can be used. The
end user should fully validate the chosen crystal across
all the expected design parameters of the system to
ensure correct operation.
The following crystals have been tested and shown to
work with the MCP7940X:
• CM200S 12pF surface mount crystals from
• ECS-.327 12pF surface mount crystals from ECS
• CFS206 12pF leaded crystals from Citizen
This is not a definitive list and all crystals should be
tested in the target application across all temperature,
voltage and other significant environmental conditions.
V
V
V
single bit I/O
available in V
CC
CC
CC
Citizen
INC
BAT
< V
> V
> V
BAT
mode. The Alarm Output is the only mode that
BAT
Condition
TRIP
TRIP
TRIP
BAT
Supply
point is defined as 1.5V typical. When V
MFP
V
CRYSTAL SPECS
feature is not being used, the V
, V
, V
, V
BAT
BAT
pin.
BAT
CC
CC
CC
mode, other modes are suspended.
< V
< V
> V
mode
BAT
BAT
BAT
2011 Microchip Technology Inc.
Read/Write
Access
BAT
Yes
Yes
No
mode
BAT
supply. The
Powered
V
BAT
V
V
By
BAT
CC
CC
pin
DD