Knowledge Base

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

Knowledge Base

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.

Datasheets

Com Pi Datasheet

DS2482S (1-Wire Interface)

MAX3232E (RS232 Interface)

Compatibility Chart

Model Compatible
Model A Yes
Model B Yes
Model A+ Yes
Model B+ Yes
Model 2B Yes
Pi Zero Yes

 

Input Ratings & Specifications

Vdd (5V input pin): 5.0V

Maximum current on 1-Wire pins: ±20 mA

I2C SDA/SCL voltage: 5.0 V

I2C port current: 100 mA

Mechanical Drawings

Click the image to enlarge

Sample Code & Tutorials

Configuring the RS232 communication on the Raspberry Pi

Configuring and using the 1-Wire® port on your Raspberry Pi


Was this article helpful? Yes No

Please tell us how we can improve this article:

Submit
Created 24/11/2016 | Last Updated: 11/11/2023

Related Expansion Boards

Related Articles

ADC Pi (Discontinued)
ADC Pi V1 and V2 expansion boards
Serial Pi (Discontinued)
Serial Pi RS232 Expansion board
Expander Pi (Discontinued)
Information for Expander Pi expansion board Legacy Product
Logic Level Converter (Discontinued)
Information for Logic level converter
RTC Pi (Discontinued)
Product Information for the version one RTC Pi board
ADC DAC Pi (Discontinued)
2 Channel ADC and 2 Channel DAC for the Raspberry Pi
Buffer Pi - Legacy Product
Bi-directional voltage-level translator for the Raspberry Pi
RTC Alarm Pi (Discontinued)
RTC Clock Module with alarm for the Raspberry Pi
Com Pi (Discontinued)
Com Pi for the Raspberry Pi
IO Pi Plus 1.0 (Discontinued)
IO Pi Plus 1.0 Legacy version information
Delta-Sigma Pi (Discontinued)
Delta-Sigma Pi ADC Board
IO Pi (Discontinued)
IO Pi Expansion board
IO Pi Zero (Discontinued)
Legacy product information for the IO Pi Zero
1 Wire Pi (Discontinued)
1 Wire Pi expansion board legacy information
1 Wire Pi Plus 1.0 (Discontinued)
1 Wire Pi Plus 1.0 - Legacy version information