MCP7952X/MCP7951X
2.0
PIN DESCRIPTION
2.6
X1, X2
The X1 and X2 pins connect to the on-board oscillator
block. X1 is the input to the module and X2 is the out-
put of the module. The device can be run from an
external CMOS signal by feeding into the X1 pin. If
driving X1 the X2 pin should be a No Connect.
The descriptions of the pins are listed in
FIGURE 2-1:
DEVICE PINOUTS
MSOP/TDFN
X1
X2
1
10
Vcc
MFP
SCK
SO
SI
MCP795XX
2
3
4
5
9
8
7
6
2.7
V
BAT
V
BAT
CS
V
SS
The V
BAT
pin is a secondary supply input to maintain
the Clock and SRAM contents when V
CC
is removed.
TABLE 2-1:
Pin Name
V
SS
X1
X2
V
BAT
V
CC
SI
SCK
CS
MFP
SO
PIN DESCRIPTIONS
Pin Function
Ground
Xtal Input, External Oscillator Input
Xtal Output
Battery Backup Input (3V Typ)
+1.8V to +3.6V Power Supply
Serial Input
Serial Clock
Chip Select
Multifunction Pin
Serial Output
2.1
Chip Select (CS)
A low level on this pin selects the device. A high level
deselects the device and forces it into Standby mode.
However, a programming cycle which is already initi-
ated or in progress will be completed, regardless of the
CS input signal. If CS is brought high during a program
cycle, the device will go in Standby mode as soon as
the programming cycle is complete. When the device is
deselected, SO goes into the high-impedance state,
allowing multiple parts to share the same SPI bus. A
low-to-high transition on CS after a valid write
sequence initiates an internal write cycle. After power-
up, a low level on CS is required prior to any sequence
being initiated.
2.2
Serial Output (SO)
The SO pin is used to transfer data out of the
MCP795XX. During a read cycle, data is shifted out on
this pin after the falling edge of the serial clock.
2.3
Serial Input (SI)
The SI pin is used to transfer data into the device. It
receives instructions, addresses and data. Data is
latched on the rising edge of the serial clock.
2.4
Serial Clock (SCK)
The SCK is used to synchronize the communication
between a master and the MCP795XX. Instructions,
addresses or data present on the SI pin are latched on
the rising edge of the clock input, while data on the SO
pin is updated after the falling edge of the clock input.
2.5
Multifunction Pin (MFP)
The MFP pin is shared with the clock divider and the
alarms. This pin requires an external pull-up to V
CC
or
V
BAT
. The pin remains low until such time that the inter-
rupt flag in the register is cleared by software. This pin
has a maximum sink current of 10mA.
DS22300A-page 6
Preliminary
2012 Microchip Technology Inc.
MAS [ MICRO ANALOG SYSTEMS ]
