# Development & Maintenance **URL:** https://forum.opencyphal.org/c/dev/5.md?page=2 [Latest](https://forum.opencyphal.org/latest.md) · [Categories](https://forum.opencyphal.org/categories.md) **Page:** 3 --- ## [V0, tail data optimization. & time slot optimisation](https://forum.opencyphal.org/t/v0-tail-data-optimization-time-slot-optimisation/1287)
**Author:** [@Maxim](https://forum.opencyphal.org/u/Maxim)\ **Replies:** 1\ **Last updated:** [June 4, 2021, 6:57pm UTC](https://forum.opencyphal.org/t/v0-tail-data-optimization-time-slot-optimisation/1287 "2021-06-04T18:57:33Z")
Hello. At the moment I am writing a program manager for the uavcan network, for internal use. When testing sending and receiving uavcan.protocol.debug.LogMessage messages under a low network load (up to 100 messages pe… --- ## [CNC machine control](https://forum.opencyphal.org/t/cnc-machine-control/1016)
**Author:** [@mawildoer](https://forum.opencyphal.org/u/mawildoer)\ **Replies:** 5\ **Last updated:** [December 20, 2020, 7:24pm UTC](https://forum.opencyphal.org/t/cnc-machine-control/1016 "2020-12-20T19:24:20Z")
Hi UAVCAN community! I really like your protocol, design and philosophy. I intend to use UAVCAN for my latest machine controller and am seeking community input into the protocol design, potentially co-conspirators and … --- ## [Handling mixed v0/v1 and Classic CAN / CAN FD networks](https://forum.opencyphal.org/t/handling-mixed-v0-v1-and-classic-can-can-fd-networks/1230)
**Author:** [@tridge](https://forum.opencyphal.org/u/tridge)\ **Replies:** 8\ **Last updated:** [May 10, 2021, 1:11pm UTC](https://forum.opencyphal.org/t/handling-mixed-v0-v1-and-classic-can-can-fd-networks/1230 "2021-05-10T13:11:42Z")
One of the key things that will determine if v1 gains traction or if it causes users to regret ever considering using it is how well we handle the transition between v0 and v1, and also handle mixed networks. We should … --- ## [UAVCAN v1.0 and ArduPilot](https://forum.opencyphal.org/t/uavcan-v1-0-and-ardupilot/671)
**Author:** [@tridge](https://forum.opencyphal.org/u/tridge)\ **Replies:** 32\ **Last updated:** [April 26, 2021, 12:53am UTC](https://forum.opencyphal.org/t/uavcan-v1-0-and-ardupilot/671 "2021-04-26T00:53:59Z")
I thought I should put together some of the thoughts we’re having in the ArduPilot dev community regarding UAVCAN v1.0 versus the existing v0 protocol. I’m one of the people leading the effort for UAVCAN in ArduPilot, an… --- ## [V1.0 release checklist](https://forum.opencyphal.org/t/v1-0-release-checklist/1190)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 2\ **Last updated:** [April 12, 2021, 5:27pm UTC](https://forum.opencyphal.org/t/v1-0-release-checklist/1190 "2021-04-12T17:27:05Z")
The old combinatorial explosion problem in PyDSDL was one of the potential release blockers because it may have required amendments to the DSDL specification. The problem was fixed recently so this blocker is removed (no… --- ## [Open Source Contribution Standards](https://forum.opencyphal.org/t/open-source-contribution-standards/1128)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 1\ **Last updated:** [February 23, 2021, 9:40am UTC](https://forum.opencyphal.org/t/open-source-contribution-standards/1128 "2021-02-23T09:40:11Z")
I’d like to start a discussion that yields a standard set of contribution standards for the UAVCAN reference implementations. These standards would be prepended to all CONTRIBUTING.md files in our repositories. I’ll open… --- ## [2020 recap and roadmap](https://forum.opencyphal.org/t/2020-recap-and-roadmap/1051)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 0\ **Last updated:** [December 31, 2020, 4:24pm UTC](https://forum.opencyphal.org/t/2020-recap-and-roadmap/1051 "2020-12-31T16:24:48Z")
In 2020, UAVCAN has reached stability. The preview Specification v1.0-alpha was released in January 2020, followed up by the stable v1.0-beta in October 2020. The final v1.0 release is expected around February 2020 or as… --- ## [Alternative transport protocols in UAVCAN](https://forum.opencyphal.org/t/alternative-transport-protocols-in-uavcan/324)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 46\ **Last updated:** [December 12, 2020, 8:27pm UTC](https://forum.opencyphal.org/t/alternative-transport-protocols-in-uavcan/324 "2020-12-12T20:27:10Z")
This post is the result of my limited research into alternative transports conducted over the last two weeks. It is assumed that the reader is familiar with the latest draft of the specification v1.0. (Aug 2019 edit: th… --- ## [Default extent considered harmful](https://forum.opencyphal.org/t/default-extent-considered-harmful/972)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 5\ **Last updated:** [November 9, 2020, 5:53pm UTC](https://forum.opencyphal.org/t/default-extent-considered-harmful/972 "2020-11-09T17:53:11Z")
I am proposing a change for the GA release of UAVCAN v1 where we remove the default extent specified in section 3.4.5.5 and change this section to read: By default, a definition is not sealed unless explicitly indicate… --- ## [Data type extensibility and composition](https://forum.opencyphal.org/t/data-type-extensibility-and-composition/827)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 20\ **Last updated:** [October 28, 2020, 4:06pm UTC](https://forum.opencyphal.org/t/data-type-extensibility-and-composition/827 "2020-10-28T16:06:20Z")
The ability to mutate data type definitions as the systems they describe evolve is essential because here on Earth there is no such thing as a stable design unless it is obsolete. Being designed for high-integrity deeply… --- ## [UAVCAN Specification v1.0-beta is available](https://forum.opencyphal.org/t/uavcan-specification-v1-0-beta-is-available/958)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 1\ **Last updated:** [October 23, 2020, 5:02pm UTC](https://forum.opencyphal.org/t/uavcan-specification-v1-0-beta-is-available/958 "2020-10-23T17:02:28Z")
--- ## [Publish request and single frame message](https://forum.opencyphal.org/t/publish-request-and-single-frame-message/963)
**Author:** [@r00tc0d3](https://forum.opencyphal.org/u/r00tc0d3)\ **Replies:** 2\ **Last updated:** [October 19, 2020, 7:49pm UTC](https://forum.opencyphal.org/t/publish-request-and-single-frame-message/963 "2020-10-19T19:49:49Z")
Hi all, For some time I am creating a CAN/Serial/Network protocol for equipment we are designing. After searching around to get some inspiration I found UAVCAN. The way UAVCAN is using the CAN transport is surprisingly … --- ## [UAVCAN/serial: issues with DMA friendliness and bandwidth overhead](https://forum.opencyphal.org/t/uavcan-serial-issues-with-dma-friendliness-and-bandwidth-overhead/846)
**Author:** [@VadimZ](https://forum.opencyphal.org/u/VadimZ)\ **Replies:** 48\ **Last updated:** [October 10, 2020, 5:03pm UTC](https://forum.opencyphal.org/t/uavcan-serial-issues-with-dma-friendliness-and-bandwidth-overhead/846 "2020-10-10T17:03:57Z")
Hi @pavel.kirienko and the forum, I’m posting this in the hope to better understand which requirements are the central to the use case UAVCAN/serial attempts to address. Because while the UAVCAN ecosystem has the poten… --- ## [UAVCAN v1.x and CAN XL](https://forum.opencyphal.org/t/uavcan-v1-x-and-can-xl/950)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 2\ **Last updated:** [October 4, 2020, 4:47am UTC](https://forum.opencyphal.org/t/uavcan-v1-x-and-can-xl/950 "2020-10-04T04:47:24Z")
Here is a copy-pasta from today’s CiA newsletter: “We are not going to support CAN FD; we are waiting for CAN XL.” I heard this statement several times and was surprised. CAN FD and CAN XL are not in competition. They … --- ## [Removal of the physical layer specification](https://forum.opencyphal.org/t/removal-of-the-physical-layer-specification/895)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 1\ **Last updated:** [July 30, 2020, 9:36am UTC](https://forum.opencyphal.org/t/removal-of-the-physical-layer-specification/895 "2020-07-30T09:36:39Z")
@scottdixon proposed that we remove the physical layer specification chapter from the UAVCAN Specification document: As discussed on the dev call, the physical layer specification for CAN transports is significantly l… --- ## [Big-endian vs. little-endian in the context of bit-level encoding](https://forum.opencyphal.org/t/big-endian-vs-little-endian-in-the-context-of-bit-level-encoding/428)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 31\ **Last updated:** [July 22, 2020, 9:52am UTC](https://forum.opencyphal.org/t/big-endian-vs-little-endian-in-the-context-of-bit-level-encoding/428 "2020-07-22T09:52:56Z")
A minute of weird questions and low-profile self doubt. I would like everyone who cares about bit layouts and also @scottdixon and @kjetilkjeka (even if they don’t) to squint at the following diagrams and see if one of … --- ## [Serialization example on page 32, section 3.7.5](https://forum.opencyphal.org/t/serialization-example-on-page-32-section-3-7-5/882)
**Author:** [@al.guryanow](https://forum.opencyphal.org/u/al.guryanow)\ **Replies:** 3\ **Last updated:** [July 22, 2020, 1:49am UTC](https://forum.opencyphal.org/t/serialization-example-on-page-32-section-3-7-5/882 "2020-07-22T01:49:21Z")
It seems to me that the serialization example on page 32 in section 3.7.5 contains an error. The value of ‘first’ is +48858, it’s binary representation is 1011\_1110\_1101\_1010. But because it’s declared as ‘truncated uint… --- ## [UAVCAN/CAN: CAN FD profile](https://forum.opencyphal.org/t/uavcan-can-can-fd-profile/867)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 1\ **Last updated:** [July 9, 2020, 5:54am UTC](https://forum.opencyphal.org/t/uavcan-can-can-fd-profile/867 "2020-07-09T05:54:51Z")
The alpha specification notably lacks coverage of the CAN FD parameters. In connection with the ongoing work on the UAVCAN Drone Profile there were proposals to use a fixed ratio of data/nominal bit rate of two. I think … --- ## [On CAN cable impedance and RJ45 connectors](https://forum.opencyphal.org/t/on-can-cable-impedance-and-rj45-connectors/845)
**Author:** [@Gijs\_Bruining](https://forum.opencyphal.org/u/Gijs_Bruining)\ **Replies:** 5\ **Last updated:** [May 30, 2020, 12:12pm UTC](https://forum.opencyphal.org/t/on-can-cable-impedance-and-rj45-connectors/845 "2020-05-30T12:12:43Z")
Hi all, I recently stumbled upon this project and I love the work you’re doing here. I just performed my first read-through of the UAVCAN Standard V1.0-alpha, so I might not fully grasp all the details (yet). Anyway, one… --- ## [PR preparations for the upcoming UAVCAN v1.0 release: new website, new logo](https://forum.opencyphal.org/t/pr-preparations-for-the-upcoming-uavcan-v1-0-release-new-website-new-logo/353)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 31\ **Last updated:** [May 28, 2020, 7:00pm UTC](https://forum.opencyphal.org/t/pr-preparations-for-the-upcoming-uavcan-v1-0-release-new-website-new-logo/353 "2020-05-28T19:00:54Z")
Please check out the brand new website we have put together here: https://new.uavcan.org. It is designed to be a simple landing page only; the specification is now available in a separate PDF document (which I am still w… --- ## [Data type regulation policy and membership fees](https://forum.opencyphal.org/t/data-type-regulation-policy-and-membership-fees/707)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 27\ **Last updated:** [May 21, 2020, 4:24pm UTC](https://forum.opencyphal.org/t/data-type-regulation-policy-and-membership-fees/707 "2020-05-21T16:24:40Z")
@lorenz.meier predicts that the current set of regulated data type management policies is unsustainable. In his view, the current approach where we combat fragmentation of interfaces used in the UAVCAN ecosystem by encou… --- ## [V0 and v1 coexist](https://forum.opencyphal.org/t/v0-and-v1-coexist/779)
**Author:** [@deekay](https://forum.opencyphal.org/u/deekay)\ **Replies:** 1\ **Last updated:** [March 13, 2020, 5:13pm UTC](https://forum.opencyphal.org/t/v0-and-v1-coexist/779 "2020-03-13T17:13:01Z")
Hi! I read that the toggle bit can be used to distinguish v0 and v1 of the protocol. Will there be an API support for this in libuavcan/libcanard? Or will it be up to user to develop their own transport layer decoding… --- ## [Proposed change to variable-length arrays](https://forum.opencyphal.org/t/proposed-change-to-variable-length-arrays/740)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 7\ **Last updated:** [March 6, 2020, 4:42pm UTC](https://forum.opencyphal.org/t/proposed-change-to-variable-length-arrays/740 "2020-03-06T16:42:29Z")
In the spirit of simplification over optimization I think we should change the default serialization behaviour of variable-length arrays and then introduce an advanced option to reenable the existing bandwidth-optimized … --- ## [What should our logging format be?](https://forum.opencyphal.org/t/what-should-our-logging-format-be/764)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 6\ **Last updated:** [February 25, 2020, 4:41pm UTC](https://forum.opencyphal.org/t/what-should-our-logging-format-be/764 "2020-02-25T16:41:25Z")
I long for a logging format in the specification. The requirements for a logging format: Self-describing – We want a way to persist data without needed external links to message definitions. Storage Efficient – The f… --- ## [YAGNI, KISS, and @union](https://forum.opencyphal.org/t/yagni-kiss-and-union/742)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 4\ **Last updated:** [February 13, 2020, 5:41pm UTC](https://forum.opencyphal.org/t/yagni-kiss-and-union/742 "2020-02-13T17:41:24Z")
I’d like to propose removing unions from the specification to reduce some complexity and to make the wire-level protocol easier to comprehend. The tagged union introduces a second, variable-length data construct which re… --- ## [Future Proposal: Featherweight Profile](https://forum.opencyphal.org/t/future-proposal-featherweight-profile/743)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 3\ **Last updated:** [February 4, 2020, 2:37pm UTC](https://forum.opencyphal.org/t/future-proposal-featherweight-profile/743 "2020-02-04T14:37:03Z")
What if we defined a sub-set of UAVCAN designed to be even simpler and more deterministic, requiring no dynamic memory allocation of any kind allowing for more primitive memory management, and eliminating some of the mor… --- ## [UAVCAN Specification v1.0-alpha is available](https://forum.opencyphal.org/t/uavcan-specification-v1-0-alpha-is-available/732)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 1\ **Last updated:** [January 29, 2020, 7:38pm UTC](https://forum.opencyphal.org/t/uavcan-specification-v1-0-alpha-is-available/732 "2020-01-29T19:38:33Z")
A recently merged pull request marked the release of UAVCAN Specification v1.0-alpha. Please read it here: --- ## [Why does the alpha specification call the variable-length array length "implicit"?](https://forum.opencyphal.org/t/why-does-the-alpha-specification-call-the-variable-length-array-length-implicit/736)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 1\ **Last updated:** [January 29, 2020, 7:32am UTC](https://forum.opencyphal.org/t/why-does-the-alpha-specification-call-the-variable-length-array-length-implicit/736 "2020-01-29T07:32:04Z")
In Section 3.7.4.2 “Variable-length array types” the length field is described as “implicit”. Why is it implicit? It seems fairly explicit to me. Am I missing some subtlety? --- ## [RTOS CAN API requirements](https://forum.opencyphal.org/t/rtos-can-api-requirements/706)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 3\ **Last updated:** [December 23, 2019, 11:51pm UTC](https://forum.opencyphal.org/t/rtos-can-api-requirements/706 "2019-12-23T23:51:29Z")
Some time ago we discussed that I should put together a list of requirements for a CAN API that has to be implemented in NuttX to make it usable with UAVCAN implementations without the need to access the underlying CAN h… --- ## [Weekly dev call - Meeting notes](https://forum.opencyphal.org/t/weekly-dev-call-meeting-notes/240)
**Author:** [@kjetilkjeka](https://forum.opencyphal.org/u/kjetilkjeka)\ **Replies:** 23\ **Last updated:** [November 27, 2019, 6:25pm UTC](https://forum.opencyphal.org/t/weekly-dev-call-meeting-notes/240 "2019-11-27T18:25:12Z")
This topic is only for collaborating on notes from the weekly dev call. There will only be one post per meeting. It will be created before the meeting, and edited several times. Feel free to edit in items on the agend… [Previous page](https://forum.opencyphal.org/c/dev/5.md?page=1) [Next page](https://forum.opencyphal.org/c/dev/5.md?page=3)