MCP7940M 2 Low-Cost I C Real-Time Clock/Calendar with SRAM Timekeeping Features General Description Real-Time Clock/Calendar (RTCC): The MCP7940M Real-Time Clock/Calendar (RTCC) - Hours, Minutes, Seconds, Day of Week, Day, tracks time using internal counters for hours, minutes, Month, Year seconds, days, months, years, and day of week. - Leap year compensated to 2399 Alarms can be configured on all counters up to and including months. For usage and configuration, the - 12/24 hour modes 2 MCP7940M supports I C communications up to 400 Oscillator for 32.768 kHz Crystals: kHz. - Optimized for 6-9 pF crystals The open-drain, multi-functional output can be On-Chip Digital Trimming/Calibration: configured to assert on an alarm match, to output a - 1 PPM resolution selectable frequency square wave, or as a general - 129 PPM range purpose output. Dual Programmable Alarms The MCP7940M is designed to operate using a 32.768 Versatile Output Pin: kHz tuning fork crystal with external crystal load - Clock output with selectable frequency capacitors. On-chip digital trimming can be used to adjust for frequency variance caused by crystal - Alarm output tolerance and temperature. - General purpose output Low-Power Features Package Types Wide Voltage Range: SOIC, MSOP, TSSOP, PDIP - Operating voltage range of 1.8V to 5.5V TDFN Low Typical Timekeeping Current: X1 1 8 VCC X1 1 8 VCC - Operating from VCC: 1.2 A at 3.3V X2 2 7 MFP X2 2 7 MFP NC 3 6 SCL User Memory NC 3 6 SCL VSS 4 5 SDA 64-byte SRAM VSS 4 5 SDA Operating Ranges 2 2-Wire Serial Interface, I C Compatible 2 -I C clock rate up to 400 kHz Temperature Range: - Industrial (I): -40C to +85C Packages: 8-Lead SOIC, MSOP, TSSOP, PDIP and 2x3 TDFN 2012-2018 Microchip Technology Inc. DS20002292C-page 1MCP7940M FIGURE 1-1: TYPICAL APPLICATION SCHEMATIC VCC VCC VCC 8 VCC C 1 X1 X1 6 SCL MCP7940M PIC MCU C 5 2 X2 SDA X2 7 MFP VSS 4 FIGURE 1-2: BLOCK DIAGRAM VCC Power Supply VSS SCL Control Logic Configuration 2 I C Interface and Addressing SDA Seconds SRAM Minutes X1 32.768 kHz Hours Clock Divider Oscillator X2 Day of Week Digital Trimming Date Square Wave Month Alarms Output Year MFP Output Logic 2012-2018 Microchip Technology Inc. DS20002292C-page 2 32.768 KHZ