KAmodRPiRTC

Description

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.

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

The expander is adapted to cooperate also with RaspberryPi+ minicomputers

Standard equipment

Code	Description
KAmodRPiRTCr	Assembled and launched board with battery 3V (CR2032)

Schematic

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

Installation of expander on RaspberryPi+ minicomputer