Why did I make it?

After playing around with a few CAN messages on the CAN BUS network on my car I decided to create this ESP32 based CAN development board to serve as a base for future projects.

What is new in rev.D?

Revision D happened mostly because of the global chip shortage which makes it very hard to find the components originally designed in stock. As a consequence the high-side switch was replaced with the BTS452T which is capable of 1.8A max, but still keeps the nice protection features and general robustness of automotive switches.

There are other small changes that were introduced in rev.D to optimize the board layout but if you want to know more about those I recommend watching video Voltlog #390 linked at the bottom of this page.

What are the features?

An ESP32 is the processor for this board which means you not only get lots of processing power (240MHz) but also a Wifi/BT interface which you can use for remote control or OTA.

There is a built-in automotive grade DC-DC step-down converter which means you can power this board directly from the car 12V system and it will safely step down to the required 3V3. There is also reverse polarity and over-current protection on the input of the converter which ads another layer of protection on top of the protection features provided by the dc-dc converter itself.

The CAN interface transceiver used on this board is the well known, reliable, low power & high performance SN65HVD231 from TexasInstruments. This will ensure a solid & standard compliant interface is provided. You also get an on-board 120 ohm termination resistor with the option of enabling or disabling it via a solder jumper.

There is the option of ordering the board with one, two or no high side load switches assembled. The switch used on the board is automotive grade, rated for up to 1.8A and has a whole bunch of protection features built-in.

There is an on-board voltage divider tied into an ADC pin which allows you to measure the VBAT voltage and make decisions in the code based on that. You can for example put the board into deep sleep if the car battery voltage goes below a certain threshold. This is actually a limiting factor if you want to power the board from more than 12V. If you plan on powering the board from 24V for example you will need to adjust the values on this resistive divider to bring down the ADC pin voltage to below 3.3V at all times.

There is an on-board 120 ohm termination resistor which is by default disconnected through solder jumper JP1. Should your setup require a termination resistor, you can enable it by adding a solder blob to bridge the jumper.

How do you load code to the ESP32

The board can be programmed in Arduino or ESP-IDF through the provided 6 pin JST-SH VoltLink pin header. If you are in search of a nice USB/Serial programming board check out the VoltLink.

Specs

• CAN Compatible With ISO 11898-2 Standard up to 1Mbps.
• Power in: DC12 0.5A via the screw connector.
• Connectivity: 2.4GHz Wifi/BT.
• Output: high side switching of the VBAT input, up to 1.8A. (only if the option is purchased during checkout).

What you get with your order

You will get 1 x CanLite board assembled with none, one or two high-side switches depending on your option. The screw connectors are delivered separate from the board so you will have to solder those yourself.

Shipping delay & exception notice

Because of the current global situation I will not be able to ship to a list of countries as decided by the postal operators. Long delays for delivery are expected especially when shipping overseas to places like the US, Canada & Australia.