The best platform for open source, CAN-bus Arduino projects

Mar 01, 2022

Project update 5 of 14

Good News on Lead Times

by daniel k

We have some good news for backers! We are happy to announce that we have a high level of confidence the second batch of CANFDuinos will ship by October, 2022. (Early orders will still ship within the next couple of months.) To make this happen, we were forced to swap out a single component. CANFDunio was originally designed to run on Microchip’s ATSAMC21G18A, which has lead times into late 2023, so we are temporarily replacing that part with the slightly less powerful ATSAMC21G17A variant. This modification will not affect the available IO but it will change two specifications: Flash Memory Space will be 128 K rather than 256 K and RAM space will be 16 K rather than 32 K. What does that means in practical terms?

  1. The size of the programs you write (the actual lines of code) will be a bit more limited. For reference, the longest example sketches we've provided (CANTerm.ino and OBD2Logger.ino) use about 15% of the memory available on the ATSAMC21G18A, so this figure will go to 30% with the new part.
  2. The maximum size and quantity of variables you can have in a given program will be slightly more restricted as well. This is something you might need to keep in mind if you are a bit cavalier with your use of memory, especially when allocating it for CAN messages. As an example, our CAN-sniffing sketch, CANTerm.ino, uses all 32 KB of RAM made available by the ATSAMC21G18A to allocate as much space for message reception as possible (64 messages for each port, including CANFD messages, which are 64 bytes long). In other words, it maxes out the capacity of the processor but only because it does no optimization, uses no filters, and just says, "give me all the messages you can." More targeted applications like OBD2Logger.ino (used for logging OBD2 messages) and Gateway.ino (used for "filter, modify, and send" hacking applications) only require about 7 KB of memory, which is less than half of that provided by the new, more limited processor. Note that none of these programs have yet been optimized for memory. (You could probably optimize sniffing with the ATSAMC21G17A, for example, by allocating all messages to just a single port unless you are sniffing on more than one bus. (We'll look into providing sample code that does just that.)

Moving forward

We hope this new lead time is welcome news for backers and potential backers who have not yet pulled the trigger. We really appreciate your support during this challenging time for supply chains, and we look forward to delivering our on open source vision!

Kind Regards,

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