KAmodRPiRTC is a functional expander for RaspberryPi and Raspberry Pi+ minicomputers, that make possible to equip them with RTC real time clock (M41T00S from STMicroelectronics offer) integrated with the calendar and automatic battery maintaining.

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Basic features and parameters
  • compatibility with minicomputer RaspberryPi and RaspberryPi+
  • Communication with microporcessor systems via I2C interface (channel 0)
  • Embedded one-chip RTC from STMicroelectronics (M41T00S)
  • Extended I/O connector of RPi minicomputer
  • Embedded battery to maintaining of RTC work
  • Power supply voltage range 2.7...5.5VDC
  • Power consumption <400 µA

Rpi B plus.jpg

The expander is adapted to cooperate also with RaspberryPi+ minicomputers

Standard equipment
Code Description
  • Assembled and launched board with battery 3V (CR2032)

KAmodRPiRTC schemat.png

View of board

Embedded RTC

In the expander are used a single-chip RTC M41T00S from STMicroelectronics. The system is a complete calendar, it is also equipped with a monitor of the supply voltage level and an automatic switch connecting the battery supply voltage in the event of a failure of the main supply voltage. The M41T00S chip communicates with the microprocessor of the RPi minicomputer (RPi+) using the I2C interface (channel 0).


The lines used for RTC communication with the microprocessor are shown in the table below.

Line Function Number of GPIO pin Comments
GPIO2 SDA 3 Lines pulled up to +3,3 V with 4,7kΩ resistors
GPIO3 SCL 5 Lines pulled up to +3,3 V with 4,7kΩ resistors
Installation of expander on RaspberryPi minicomputer
KamodRTC RPi.jpg

Installation of expander on RaspberryPi+ minicomputer
KamodRTC RPi B plus.jpg