BMT DS1302 Real Time Clock Module with Backup Battery Socket

The BMT Real Time Clock - DS1302 Module is a compact, reliable, and low-power RTC (Real Time Clock) solution designed for accurate timekeeping in embedded systems, robotics, IoT projects, automation systems, and educational electronics. Built around the Dallas DS1302 RTC chip, this module provides precise tracking of seconds, minutes, hours, day, date, month, and year, with automatic leap-year compensation up to the year 2100.

This module is ideal for projects that require persistent time and date memory, even when the main power supply is removed. It features a backup battery socket for a CR2032 coin cell (battery not included), allowing the clock and onboard RAM to retain data for many years without external power.

Designed for both beginners and professionals, the module supports 3.3V and 5V systems, making it fully compatible with Arduino, Raspberry Pi (via logic level interface), ESP boards, PIC, AVR, STM32, and other microcontrollers.

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Key Features

• DS1302 Real Time Clock IC
• Tracks: seconds, minutes, hours, day, date, month, year
• Automatic leap year correction
• 12-hour / 24-hour time format support
• 31 bytes onboard static RAM for data storage
• Ultra-low power consumption (<1mW operation)
• CR2032 backup battery support (battery not included)
• Trickle-charge capable RTC architecture
• Dual power supply system (main power + backup battery)
• 32.768kHz high-precision crystal oscillator
• TTL compatible logic levels
• Low current draw ( 300nA at 2.0V operation)
• High reliability and long-term stability
• 4 PCB mounting holes for secure installation
• Large DIP IC socket for easy chip replacement
• Compact, single-layer PCB design

Interface & Communication

The DS1302 uses a simple 3-wire serial interface, making integration extremely easy:

• RST - Reset
• DAT - Data (I/O)
• CLK - Serial Clock

This allows fast, reliable communication with minimal GPIO usage on your microcontroller.

Electrical Specifications

• Operating Voltage: 2.0V - 5.5V
• Module Compatibility: 3.3V / 5V systems
• Backup Battery: CR2032 (3V, non-rechargeable - not included)
• Crystal Frequency: 32.768kHz
• Current Consumption: <300nA at 2.0V
• Power Mode: Dual supply (main + backup)
• Logic Level: TTL compatible

Mechanical Specifications

• PCB Size: 44 × 23 × 1.6 mm
• Mounting Holes: 4 × Ø 3.1 mm
• Crystal Size: 2 × 6 mm
• PCB Type: Single-layer board
• Chip Package: 8-pin DIP in IC socket

Environmental Specifications

• Operating Temperature: 0 C to 70 C
• Optional Industrial Range Support: -40 C to +85 C (chip capability)
• Long-term data retention: >10 years (with CR2032 battery)

Typical Wiring Example

• VCC +5V or 3.3V
• GND Ground
• CLK MCU GPIO
• DAT MCU GPIO
• RST MCU GPIO

(GPIO pins can be freely assigned and configured in software)

Applications

• Arduino & microcontroller projects
• Robotics and automation systems
• Data logging systems
• IoT devices
• Smart clocks & timers
• Alarm systems
• Embedded controllers
• Educational STEM kits
• Science projects
• Real-time scheduling systems
• Access control systems

What's in the box
1 x BMT DS1302 Real Time Clock Module with Backup Battery Socket