ESP32 is a very powerful processor with a lot of hardware drivers with in the chip that a lot of users are not taking advantage of and one of them is CAN module. Adding a small CAN transceiver chip with supporting biasing and voltage regulator we turn into a small module to which the ESP32 is plugged and turning it into a flexible CAN gateway.

Though the board is very basic it does have number of connector for CAN, I2c and UART(serial) busses which can be used for expansion and can be configured in various ways dependant of software implementation.

As the ESP has number of communication capabilities,  the board can be simply configured as WiFi or BlueTooth gateway. or a simple CAN to serial (TTL) adapter.  The I2C port can be used to expand the board to other modules or simply as tranceiver for other projects.


 

OBDII  Pin 6   to CAN H  Pin14  connected to CAN L  Pin16  Battery constant on power  Pin 4,5 chassis ground




 



 

Features of the 32u4 board


o     Plug in shield for 30pin ESP32 development kit1 board.
o    Data Rates: up to 1 Mbps
o     Compatible With ISO 11898-2
o     Cross-wire protection
o      Over temperature (thermal shutdown) protection
o      EMI and ESD CAN bus protection
o     Loop back (LBK) feature available driving GPIO33 high
o     CAN tranceiver using Rx = D4 and Tx = D5
o     Operating range of 7 to 15.5 volts (12v system)
o     Can utilize CAN B connector or 4 pin 2.54" header
o      Switch for putting CAN into Read only mode (disable transmit driver)
o      CAN termination solder jumper of switch
o      2 serial/UART connectors  JST / 2.54
o      2  I2C connectors  JST / 2.54 (internal 2.54 meant for 0.91 oLED ssh1306 display)  externally expandable through JST connector
o      LED indicators
        o Power
        o  3 General purpose
        o  1 R/WR CAN status
o     PTC fuse and diode polarity protection
o      Voltage divider to measure pin 16 battery voltage
o      User button on back of PCB
o      Board size 44mm x 66mm  (4in x2.6in)


 

Power
Powering the board is accomplished through 4 ways USB connector limited to USB port limitations normally 500mA, Vin pin (RAW), OBD connector or DC barrel isolated by steering diodes into 5V regulator. 3.3V voltage is derived from VR2A or VR2B regulators depending on the need
 



Switches / Jumpers
SW1  Used for R/RW  (disabling transmit circuit in the CAN driver
                Down puts in into Read only /  UP enables transmitter and puts in into RW mode

SW2   User function switch

SW3    CAN termination   Up enables 120 ohm resistor   Down disables termination



 

Board documents:

•    Schematic
     PCB layout files
     Gerber Files
     Bill of Materials
     Assembly / board  manual
     STL case files
  
  
  
  
  
  
  
  
  

  NOTE:
  * Copy right and trademarks of their respective owners / manufacturers