Datasheet

MCP79410/MCP79411/MCP79412
DS20002266E-page 8  2010-2013 Microchip Technology Inc.
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Tab le 3- 1.
TABLE 3-1: PIN DESCRIPTIONS
FIGURE 3-1: DEVICE PINOUTS
3.1 Serial Data (SDA)
This is a bidirectional pin used to transfer addresses
and data into and out of the device. It is an open-drain
terminal, therefore, the SDA bus requires a pull-up
resistor to V
CC (typically 10 k for 100 kHz, 2 k for
400 kHz). For normal data transfer, SDA is allowed to
change only during SCL low. Changes during SCL high
are reserved for indicating the Start and Stop
conditions.
3.2 Serial Clock (SCL)
This input is used to synchronize the data transfer from
and to the device.
3.3 X1, X2
External crystal pins for 32.768 kHz crystal and load
capacitors.
X1 = Oscillator input, also external oscillator input
X2 = Oscillator output
3.4 MFP (Multifunction Pin)
Open drain pin used for alarm and clock-out, addition-
ally the state of this pin may be changed using the OUT
bit. This pin is also controlled by the oscillator bit. See
Section 8.5 “Multifunction PIN (MFP)” for more
details. This pin may be left floating if not used.
3.5 VBAT
Input for backup supply to maintain RTCC and SRAM
during the time when V
CC is below VTRIP. See
Section 8.6 “Battery Backed Operation” for more
details.
Pin
Name
Pin Function
Pin
Number
X1 Xtal Input, External Oscillator Input 1
X2 Xtal Output 2
VBAT Battery Backup Input 3
Vss Ground 4
SDA Bidirectional Serial Data (I
2
C™) 5
SCL Serial Clock (I
2
C) 6
MFP Multifunction Pin 7
Vcc Power Supply 8
Note: Exposed pad on TFDN can be connected to
Vss or left floating.
X1
X2
V
BAT
Vss
Vcc
MFP
SCL
SDA
1
2
3
4
8
7
6
5
SOIC/TDFN/MSOP/TSSOP