RTC EoF-001

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Raspberry Pi RTC Module With Battery


This RTC module use DS3231 as its Real-Time Clock chip which has build-in crystal oscillator. This RTC module communicates with Raspberry Pi through I2C bus.DS3231 is a low power consumer RTC chip and whose back up supply is a 0.2uF Super-Capacitor,which can keep work for a week at least after power down

Compatibility List

  • Compatibility
Platform Super Capacitor RTC Notes
Raspberry Pi 4 Model B
Raspberry Pi 3 Model B Plus
Raspberry Pi zero
Raspberry Pi zero W
Raspberry Pi 3 Model B
Raspberry Pi 2 Model B
Raspberry Pi Model B+

Technical Details

Type value
Work Voltage 5V
Weight 4.35g
Maximum Current 1.5mA
VBAT Current 800nA
work temprature 0~+50℃
Crystal Oscilator Epson 20 ppm
scale 22x26x18.6(mm)
Battery CR1220
RTC chip DS3231
mount hole 2*5 Stacking Header



File:RTC CCAP01.png

LCD module scale

File:RTC CCAP02.png

DT Overlays Used

With DT enabled, this becomes a line in config.txt:

   dtoverlay=i2c-rtc ds3231

It can adds support for a number of I2C Real Time Clock devices


  • Type in [sudo raspi-config] set up raspberry pi and prepare to enable i2c interface

File:RTC tech02.png

  • select Advanced Options

File:RTC tech03.png

  • select I2c

File:RTC tech04.png

  • select yes enable I2C

File:RTC tech05.png

  • type in [sudo vim.tiny /etc/modules] to open file modules

File:RTC tech06.png

  • add i2c-dev device like picture below

File:RTC tech07.png

  • install i2c-tools ,type in [sudo apt-get install i2c-tools]

File:RTC tech08.png

  • type in [sudo reboot] wait the raspberry pi restart ,Then type in [sudo i2cdetect –y 1], if RTC works ,it should be like picture below

File:RTC tech09.png

  • Type in [sudo su –] change root user,then Type in [modprobe i2c-dev] to load I2C device

File:RTC tech10.png

  • Type in [echo "ds1307 0x68" > /sys/class/i2c-adapter/i2c-1/new_device] add RTC to system

File:RTC tech11.png

  • Then you can use “hwclock” command to use this RTC module

If you want to know more about hwclock command you can type in “man hwclock” to get details A brief description like following: Command [hwclock –r] to get RTC time Command [hwclock -w]set the system time to RTC time Like following
File:RTC tech12.png


ds3231 date sheet