Knowledge Base

The AB Electronics UK Knowledge Base provides support solutions, tutorials and troubleshooting guides.

Com Pi (Discontinued)

Com Pi for the Raspberry Pi

Hardware mounting kit and GPIO extension header included.
RS232 Master Port.
Control the Raspberry Pi over RS232 or connect to external serial accessories.
1-Wire® to I2C host interface with ESD protection diode.
Stackable with other Raspberry Pi accessory boards.
Buffered 5V I2C port.
External 5V power input for the 1-Wire® interface.

The Com Pi from AB Electronics is a communication add-on board for the Raspberry Pi supporting RS232 and 1-Wire® protocols. A 5V buffered I2C port is also provided on the board.

The Com Pi is pin compatible with the Raspberry Pi model B+.

The RS232 port is connected to the UART port on the Raspberry Pi using a MAX3232 interface. The MAX3232 IC converts the 3.3V UART port to RS232 voltages allowing communication with RS232 compatible devices over a DB9 serial cable or using a null-modem cable. The board allows terminal access with Linux on the Raspberry Pi using a terminal application. The RS232 port can be accessed through the DB9 port or the solder points on the PCB.

The 1-Wire® port is based around a DS2482-100 I2C to 1-Wire® bridge device. The DS2482-100 provides bi-directional protocol conversion between the I2C port on the Raspberry Pi and any attached 1-Wire® devices. An ESD Protection Diode protects the Com Pi and Raspberry Pi from electrostatic spikes on the 1-Wire® port. Connections to the 1-Wire® port can be made through the RJ-12 socket or the solder points on the PCB. Wiring diagrams for the RS232 and 1-Wire® ports are on the Com Pi datasheet.

A 5V input port allows you to use an external power supply on the 1-Wire® interface, reducing the load on the Raspberry Pi. If you use the external 5V input, please remove the jumper on the board to isolate the Raspberry Pi 5V bus.