Beaglebone Black LCD4-CAN

The Beaglebones CAN interface requires a driver circuit to convert the logic level RX&TX signals to CAN differential bus. To archive that I have designed my own board that holds a fully isolated CAN driver and, because this is going to be connected to a car, a DC-DC converter to power the Beaglebone main board. With that setup the monitoring device is plug-and-play with just for wires connecting to the Prius electrical network.

LCD cape with fully isolated CAN driver and power supply.

LCD cape with fully isolated CAN driver and power supply.

For the power supply part I´m using a TDK CC6-1205-SRE DC-DC converter that provides 5V/1.2A from 9-18V input voltage. On a Prius with its dual battery setup that is just fine. When used in an ordinary car the input voltage range should be enough to cover also input voltage drops when the starter engages.

Another top tip: A single Lithium-Polymer battery cell can be connected to the Beaglebone. It buffers the internal power supply in case of external surge conditions. The Beaglebone will keep the battery charged when external power is sufficient. The battery allows also an extended runtime when external power is disconnected, in example to ensure a clean system shutdown.

The CAN interface driver consist of a Texas Instruments ISO1050 driver IC and a Recom R1S-3.305 DC-DC converter. Some passive components are used to stay within the Beaglebone signal requirements during reset state. This design ensures full isolated operation of the Beaglebone from the Prius electrical and CAN bus network.

Size of the driver board is just right to fit between the two GPIO headers on the LCD cape. Pads are located in a way to use just some short jump wires for connections to the LCD cape. Four pads, accessible when the cape is attached to the Beaglebones main board, are providing the connection to the Prius. The board is single sided and therefore can be made cheap, even home-brew style.

Short jump wires connecting the driver board to the LCD cape.

Short jump wires connecting the driver board to the LCD cape.

The driver board is held in place by some hot glue.

Everything fits nice and clear.

Everything fits nice and clear.

Download files for your own build:

BBBK LCD4-CAN Components
BBBK LCD4-CAN Components
BBBK-LCD4-CAN-Components.pdf
Version: A
15.9 KB
200 Downloads
Details
BBBK LCD4-CAN Device Tree Binary Blob
6.2 KB
103 Downloads
Details
BBBK LCD4-CAN Device Tree Source Code
8.9 KB
108 Downloads
Details
BBBK LCD4-CAN Layout
BBBK LCD4-CAN Layout
BBBK-LCD4-CAN-Layout.pdf
Version: A
10.4 KB
203 Downloads
Details
BBBK LCD4-CAN Layout CAD
BBBK LCD4-CAN Layout CAD
BBBK-LCD4-CAN_PCB.T3001
Version: A
50.5 KB
177 Downloads
Details
BBBK LCD4-CAN Schematic
BBBK LCD4-CAN Schematic
BBBK-LCD4-CAN-Schematic.pdf
Version: A
12.4 KB
245 Downloads
Details
All parts available at Digikey.

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