Add custom overlay for MCP2517FD for Raspberry pi 4 for CAN bus FD

dreyplatt · September 20, 2020, 4:23am

So, I am trying to interface with the can bus hat from seeed studio using the raspberry pi 4.

This new board uses the newer mcp2517fd chip instead of the notorious mcp2515 chip which is built into raspbian. I need to now add this overlay to

/resin-boot/overlays

I see the

mcp2515-can0.dtbo

overlay. Of course resin-boot is read only so I have to do something before it starts up, but have no idea what that would be.

phil-d-wilson · September 21, 2020, 8:28am

Hi Drey!

I’m glad to see you’re still fighting! We’re working in the background to try and work out your Beaglebone Green issue with CANbus, but moving over to a more capable device might be a good step anyway.

So to this issue, you can use our special configurable variables to set DT Overlays:

This page gives some guidance for the overlay you’re trying to use:

github.com

raspberrypi/linux/blob/rpi-4.19.y/arch/arm/boot/dts/overlays/README

Introduction
============

This directory contains Device Tree overlays. Device Tree makes it possible
to support many hardware configurations with a single kernel and without the
need to explicitly load or blacklist kernel modules. Note that this isn't a
"pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices
are still configured by the board support code, but the intention is to
eventually reach that goal.

On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By
default, the Raspberry Pi kernel boots with device tree enabled. You can
completely disable DT usage (for now) by adding:

    device_tree=

to your config.txt, which should cause your Pi to revert to the old way of
doing things after a reboot.

In /boot you will find a .dtb for each base platform. This describes the

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Hope this helps. Keep going, we’ll get you sorted!

Phil