Datasheet

 2012-2018 Microchip Technology Inc. DS20002300C-page 2
MCP7951X/MCP7952X
Description
The MCP795XX Real-Time Clock/Calendar (RTCC)
tracks time using internal counters for hours, minutes,
seconds, hundredth of seconds, days, months, years
and day of week. Alarms can be configured on all
counters up to and including months. For usage and
configuration, the MCP795XX supports SPI
communications up to 5 MHz.
The MCP795XX is designed to operate using a
32.768 kHz tuning fork crystal with external crystal
load capacitors. On-chip digital trimming can be used
to adjust for frequency variance caused by crystal
tolerance and temperature.
SRAM and timekeeping circuitry are powered from the
backup supply when main power is lost, allowing the
device to maintain accurate time and the SRAM
contents. The times when the device switches over to
the backup supply and when primary power returns
are both logged by the power-fail timestamp.
The MCP795XX features 128 bits of EEPROM which
is only writable after an unlock sequence, making it
ideal for storing a unique ID or other critical
information. The MCP795X1 and MCP795X2 are
preprogrammed with EUI-48 and EUI-64 addresses,
respectively. Custom programming is also available.
The MCP795XX has a shared pin for outputting a
selectable frequency square wave or alarm signals.
FIGURE 1-1: TYPICAL APPLICATION SCHEMATIC
VCC VCCVCC
VBAT
C
X1
32.768 KHZ
C
X2
VBAT
X2
X1
CS
SCK
SI
V SS
VCC
1
2
3
5
8
6
4
10
PIC
®
MCU
MCP795XX
SO
7
9
MFP