# LibCyphal **URL:** https://forum.opencyphal.org/c/app/libcyphal/7.md [Latest](https://forum.opencyphal.org/latest.md) · [Categories](https://forum.opencyphal.org/categories.md) --- ## [About the LibCyphal category](https://forum.opencyphal.org/t/about-the-libcyphal-category/16)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 0
LibCyphal is a portable reference implementation in C++ for embedded systems and Linux. --- ## [Looking for Minimal C++ Server-Client Example to Get Started with libcyphal. (OpenCyphal Beginner)](https://forum.opencyphal.org/t/looking-for-minimal-c-server-client-example-to-get-started-with-libcyphal-opencyphal-beginner/2815)
**Author:** [@andy27182](https://forum.opencyphal.org/u/andy27182)\ **Replies:** 1\ **Last updated:** [June 5, 2026, 12:09pm UTC](https://forum.opencyphal.org/t/looking-for-minimal-c-server-client-example-to-get-started-with-libcyphal-opencyphal-beginner/2815 "2026-06-05T12:09:27Z")
Hi, I’m learning OpenCyphal and libcyphal. I’ve set up my development environment via DevContainer and cloned the libcyphal repository successfully. However, I’ve tried to cmake and make but cannot build a minimal runn… --- ## [Building LibCyphal](https://forum.opencyphal.org/t/building-libcyphal/2427)
**Author:** [@Scoeerg](https://forum.opencyphal.org/u/Scoeerg)\ **Replies:** 8\ **Last updated:** [November 15, 2025, 10:22pm UTC](https://forum.opencyphal.org/t/building-libcyphal/2427 "2025-11-15T22:22:25Z")
Hi, I am on my way to build my first high-level LibCyphal/CPP-based Cyphal applications. I already did libcanard on STM32, and of course PyCyphal. Finally I would like to have a my\_hello\_world top-layer cpp-application … --- ## [Uavcan v0 found data transfer reversal](https://forum.opencyphal.org/t/uavcan-v0-found-data-transfer-reversal/1476)
**Author:** [@Cherish-forever](https://forum.opencyphal.org/u/Cherish-forever)\ **Replies:** 11\ **Last updated:** [December 18, 2023, 7:37am UTC](https://forum.opencyphal.org/t/uavcan-v0-found-data-transfer-reversal/1476 "2023-12-18T07:37:50Z")
In this case we found that data: 21 50 21 8d f8 05 10 data: 4f f0 03 02 14 bf 44 transfer reversal, then data decode error. how can I process this case? I think protocol stack need consider data order. --- ## [API proposal for libcyphal](https://forum.opencyphal.org/t/api-proposal-for-libcyphal/1850)
**Author:** [@pavel.kirienko](https://forum.opencyphal.org/u/pavel.kirienko)\ **Replies:** 9\ **Last updated:** [July 3, 2023, 8:22pm UTC](https://forum.opencyphal.org/t/api-proposal-for-libcyphal/1850 "2023-07-03T20:22:06Z")
I apologize for the clickbait title as there’s actually no proposal here. I just want to share these two files here per @scottdixon’s suggestion: can.hpp (27.5 KB) generic.hpp (15.4 KB) generic.hpp contains the transp… --- ## [Design Review:: execution model for libcyphal](https://forum.opencyphal.org/t/design-review-execution-model-for-libcyphal/1918)
**Author:** [@scottdixon](https://forum.opencyphal.org/u/scottdixon)\ **Replies:** 9\ **Last updated:** [July 3, 2023, 6:29pm UTC](https://forum.opencyphal.org/t/design-review-execution-model-for-libcyphal/1918 "2023-07-03T18:29:10Z")
We are currently in the process of roughing out libcyphal APIs and will post a PR-as-design-review for these soon. Ahead of looking at that code this is the execution model we are proposing. Please review and comment: … --- ## [UAVCAN tx pin not working](https://forum.opencyphal.org/t/uavcan-tx-pin-not-working/1800)
**Author:** [@Pramod](https://forum.opencyphal.org/u/Pramod)\ **Replies:** 2\ **Last updated:** [December 9, 2022, 1:23pm UTC](https://forum.opencyphal.org/t/uavcan-tx-pin-not-working/1800 "2022-12-09T13:23:35Z")
Hi, I’m trying to configure mag sensor with uavcan interface. I’m using stm32 nucleo f413 board for this interfacing. I’ve configured uavcan stack, timers everything properly. My CAN node is not able to get dynamic nod… --- ## [allocator.getBlockCapacity() is jumping to exceptional handler](https://forum.opencyphal.org/t/allocator-getblockcapacity-is-jumping-to-exceptional-handler/1787)
**Author:** [@Pramod](https://forum.opencyphal.org/u/Pramod)\ **Replies:** 4\ **Last updated:** [November 9, 2022, 4:16pm UTC](https://forum.opencyphal.org/t/allocator-getblockcapacity-is-jumping-to-exceptional-handler/1787 "2022-11-09T16:16:15Z")
Hi, During initialization of uavcan, execution is jumping to exception handler by executing the function allocator.getBlockCapacity(). This function is called by the constructor CanIOManager::CanIOManager(). I’ve tried… --- ## [Nucleo STM32F303RE, FREERTOS node.start freeze](https://forum.opencyphal.org/t/nucleo-stm32f303re-freertos-node-start-freeze/1593)
**Author:** [@Rui\_Loureiro](https://forum.opencyphal.org/u/Rui_Loureiro)\ **Replies:** 4\ **Last updated:** [February 15, 2022, 10:06am UTC](https://forum.opencyphal.org/t/nucleo-stm32f303re-freertos-node-start-freeze/1593 "2022-02-15T10:06:06Z")
Hi everybody, I’m attempting to develop a UAVCAN subscriber node while using an STM Nucleo board and RTOS. I’m using the Nucleo STM32F303RE. I have followed the examples in this repo: https://github.com/raimapo/UAVCAN-… --- ## [Init UAVCAN and change ID](https://forum.opencyphal.org/t/init-uavcan-and-change-id/1586)
**Author:** [@Andrei\_Shumski](https://forum.opencyphal.org/u/Andrei_Shumski)\ **Replies:** 1\ **Last updated:** [January 30, 2022, 11:57am UTC](https://forum.opencyphal.org/t/init-uavcan-and-change-id/1586 "2022-01-30T11:57:00Z")
When I use function for set id, like \_node = setNodeID(123); I see next id in terminal: 268522875x (dec) or 1001557Bh (hex) Last 7B it is my 123 id which I passed to function. What means 100155 in the id? and one mo… --- ## [Problems with CANbus](https://forum.opencyphal.org/t/problems-with-canbus/1582)
**Author:** [@Andrei\_Shumski](https://forum.opencyphal.org/u/Andrei_Shumski)\ **Replies:** 1\ **Last updated:** [January 28, 2022, 4:49am UTC](https://forum.opencyphal.org/t/problems-with-canbus/1582 "2022-01-28T04:49:58Z")
I have some problems with CANbus. I try to add basic CANbus to project Plane I have two functions. First one init for CAN uint8\_t \_driver\_index = 0; uint8\_t \_interface = 0; uavcan::ICanDriver\* \_can\_driver; AP\_HAL::CANM… --- ## [Bare metal libuavcan v0 on stm32f412](https://forum.opencyphal.org/t/bare-metal-libuavcan-v0-on-stm32f412/1286)
**Author:** [@RuslanUrya](https://forum.opencyphal.org/u/RuslanUrya)\ **Replies:** 0\ **Last updated:** [June 3, 2021, 12:12pm UTC](https://forum.opencyphal.org/t/bare-metal-libuavcan-v0-on-stm32f412/1286 "2021-06-03T12:12:08Z")
Hello everybody! I using custom plate with stm32f412 and two TJA1051TK/3. I created program using libuavcan v0 without rtos (bare metal). Program allow dynamic id allocation, adjusting parameters and remote reboot. I use… --- ## [file.Read timeout even though all frames on bus](https://forum.opencyphal.org/t/file-read-timeout-even-though-all-frames-on-bus/710)
**Author:** [@deekay](https://forum.opencyphal.org/u/deekay)\ **Replies:** 16\ **Last updated:** [April 6, 2021, 5:33pm UTC](https://forum.opencyphal.org/t/file-read-timeout-even-though-all-frames-on-bus/710 "2021-04-06T17:33:19Z")
Hi! I am trying out the example class FirmwareLoader for handling background SW loading process. During my SW update process, i.e. file.Read is fetching file from service every 50ms, I notice sometimes that status\_ = E… --- ## [Legacy: STM32 assertion on TX timeout](https://forum.opencyphal.org/t/legacy-stm32-assertion-on-tx-timeout/1162)
**Author:** [@spyguyian](https://forum.opencyphal.org/u/spyguyian)\ **Replies:** 3\ **Last updated:** [March 25, 2021, 1:21pm UTC](https://forum.opencyphal.org/t/legacy-stm32-assertion-on-tx-timeout/1162 "2021-03-25T13:21:50Z")
Using legacy libuavcan and the stm32 baremetal driver, I am making a driver for a rangefinder. I have got everything to work as I like, except for if I start the program before connecting it to another CAN device (in my … --- ## [Traffic\_report CRC](https://forum.opencyphal.org/t/traffic-report-crc/1132)
**Author:** [@Maxim](https://forum.opencyphal.org/u/Maxim)\ **Replies:** 4\ **Last updated:** [February 22, 2021, 12:48pm UTC](https://forum.opencyphal.org/t/traffic-report-crc/1132 "2021-02-22T12:48:15Z")
Hello Pavel. There was a problem with the correctness of the formation of the CRC for the message ardupilot.equipment.trafficmonitor.TrafficReport. I use the canard 0.2 library. When debugging the Ardupilot CubeBlack so… --- ## [PX4 do not response to my Dynamic node ID client](https://forum.opencyphal.org/t/px4-do-not-response-to-my-dynamic-node-id-client/1086)
**Author:** [@RuslanUrya](https://forum.opencyphal.org/u/RuslanUrya)\ **Replies:** 3\ **Last updated:** [January 26, 2021, 11:48am UTC](https://forum.opencyphal.org/t/px4-do-not-response-to-my-dynamic-node-id-client/1086 "2021-01-26T11:48:09Z")
Hello. I created DynamicNodeIDClient on my device according to tutorial. It work with GUI Tool. But PX4 ignore my node and DynamicNodeIDClient spin. Does px4 any specific conditions for the DynamicNodeIDClient, that are… --- ## [How can i use libuavcan](https://forum.opencyphal.org/t/how-can-i-use-libuavcan/912)
**Author:** [@newcomer](https://forum.opencyphal.org/u/newcomer)\ **Replies:** 8\ **Last updated:** [August 21, 2020, 2:49am UTC](https://forum.opencyphal.org/t/how-can-i-use-libuavcan/912 "2020-08-21T02:49:29Z")
Can you provide me with a route or a simple example? I had read the uavcan guide,UAVCAN\_Specification\_v1.0-alpha,but i still do not how to use it . the pyuavcan seems difficult to me. --- ## [Question on adapting UAVCAN in PX4](https://forum.opencyphal.org/t/question-on-adapting-uavcan-in-px4/906)
**Author:** [@nacansino](https://forum.opencyphal.org/u/nacansino)\ **Replies:** 1\ **Last updated:** [August 7, 2020, 5:41pm UTC](https://forum.opencyphal.org/t/question-on-adapting-uavcan-in-px4/906 "2020-08-07T17:41:06Z")
Hi, So we are working on a project that will use PX4 as its flight stack (on a Pixhawk board) and is currently considering adapting UAVCAN. Our current configuration is that all data acquisition for sensors (including I… --- ## [Safeguard Parameters structure for multiple threads useage](https://forum.opencyphal.org/t/safeguard-parameters-structure-for-multiple-threads-useage/869)
**Author:** [@raimondas](https://forum.opencyphal.org/u/raimondas)\ **Replies:** 4\ **Last updated:** [July 11, 2020, 5:38pm UTC](https://forum.opencyphal.org/t/safeguard-parameters-structure-for-multiple-threads-useage/869 "2020-07-11T17:38:52Z")
Hello, How are You Pavel ? I have one question maybe You or someone could help me. Just finishing my small gimbal motor control project and left to do publisher and subsciber services. Problem are how to nicely safeguar… --- ## [Libuavcan compatibility for ATSAMC21 family microcontroller](https://forum.opencyphal.org/t/libuavcan-compatibility-for-atsamc21-family-microcontroller/824)
**Author:** [@kyle-pawlowski](https://forum.opencyphal.org/u/kyle-pawlowski)\ **Replies:** 9\ **Last updated:** [May 24, 2020, 3:54pm UTC](https://forum.opencyphal.org/t/libuavcan-compatibility-for-atsamc21-family-microcontroller/824 "2020-05-24T15:54:52Z")
Can libuavcan be used for ATSAMC21 Cortex M0 microcontrollers? If so, how can it be compiled and implemented? Does it handle all of the low-level CAN processes automatically? --- ## [Unknown Data Type](https://forum.opencyphal.org/t/unknown-data-type/812)
**Author:** [@RuslanUrya](https://forum.opencyphal.org/u/RuslanUrya)\ **Replies:** 3\ **Last updated:** [April 26, 2020, 1:37pm UTC](https://forum.opencyphal.org/t/unknown-data-type/812 "2020-04-26T13:37:57Z")
Hello! I defined my node as publisher of uavcan::equipment::actuator::command. But method pub.init of the lib return “ErrUnknownDataType”. where could there be a mistake? const int RxQueueSize = 128; static std::uint32\_… --- ## [How to debug via printf()?](https://forum.opencyphal.org/t/how-to-debug-via-printf/807)
**Author:** [@RuslanUrya](https://forum.opencyphal.org/u/RuslanUrya)\ **Replies:** 3\ **Last updated:** [April 22, 2020, 9:54am UTC](https://forum.opencyphal.org/t/how-to-debug-via-printf/807 "2020-04-22T09:54:18Z")
Hello. I have some problems with my node, so i want to see debug information. Library has this functionality. I defined UAVCAN\_DEBUG 1 and UAVCAN\_USE\_EXTERNAL\_SNPRINTF 1 for adding function for embedded system. But, UAVC… --- ## [Libuavcan driver for RTOS/DE10-Nano](https://forum.opencyphal.org/t/libuavcan-driver-for-rtos-de10-nano/792)
**Author:** [@SnaKyEyeS](https://forum.opencyphal.org/u/SnaKyEyeS)\ **Replies:** 3\ **Last updated:** [March 28, 2020, 5:47pm UTC](https://forum.opencyphal.org/t/libuavcan-driver-for-rtos-de10-nano/792 "2020-03-28T17:47:34Z")
Hello, I am currently working in a robotics project and am using some board that use the UAVCAN protocol. To control them, we are using a DE10-Nano (Cyclone V) wtih a RTOS, mAbassi, integrated. We have a custom-made MCP… --- ## [Uavcan Service call response request is empty except for the boolean fields](https://forum.opencyphal.org/t/uavcan-service-call-response-request-is-empty-except-for-the-boolean-fields/747)
**Author:** [@mohammedtalha89](https://forum.opencyphal.org/u/mohammedtalha89)\ **Replies:** 5\ **Last updated:** [February 10, 2020, 12:55pm UTC](https://forum.opencyphal.org/t/uavcan-service-call-response-request-is-empty-except-for-the-boolean-fields/747 "2020-02-10T12:55:21Z")
I am using uavcan to communicate between an IMX6 and stm32f4. stm32f4 has a configuration server which updates some parameters locally when a request is made from the IMX6::ros node. Here is the code from the IMX6 side o… --- ## [Configure Can Acceptance Filters in multi thread app](https://forum.opencyphal.org/t/configure-can-acceptance-filters-in-multi-thread-app/709)
**Author:** [@deekay](https://forum.opencyphal.org/u/deekay)\ **Replies:** 4\ **Last updated:** [December 19, 2019, 11:09pm UTC](https://forum.opencyphal.org/t/configure-can-acceptance-filters-in-multi-thread-app/709 "2019-12-19T23:09:12Z")
Hi! I am building a Node and SubNode application, similar to example in repo. Does it matter in what thread the configureCanAcceptanceFilters() is called, assuming all subscribers etc. has been setup in each thread at … --- ## [How to integrate to firmware with my own board](https://forum.opencyphal.org/t/how-to-integrate-to-firmware-with-my-own-board/712)
**Author:** [@Rsenjoyer](https://forum.opencyphal.org/u/Rsenjoyer)\ **Replies:** 3\ **Last updated:** [December 18, 2019, 8:56am UTC](https://forum.opencyphal.org/t/how-to-integrate-to-firmware-with-my-own-board/712 "2019-12-18T08:56:48Z")
hey: i want to know how to add uavcan to firmware and use with my own board Instead of stm32？ i have added uavcan as an submodule to firmware, and run git submodule update --init --recursive, it download into src/modul… --- ## [Stack behavior if error\_passive](https://forum.opencyphal.org/t/stack-behavior-if-error-passive/700)
**Author:** [@deekay](https://forum.opencyphal.org/u/deekay)\ **Replies:** 3\ **Last updated:** [December 6, 2019, 8:59pm UTC](https://forum.opencyphal.org/t/stack-behavior-if-error-passive/700 "2019-12-06T20:59:48Z")
How does the stack handle underlying errors in socketCan such as when it enters error states? For example ERROR-PASSIVE or BUS-OFF? I do not see an error code for it in error.hpp, if not ErrFailure is used for it? Or … --- ## [Which libuavcan branch for new project](https://forum.opencyphal.org/t/which-libuavcan-branch-for-new-project/701)
**Author:** [@Tecnologic](https://forum.opencyphal.org/u/Tecnologic)\ **Replies:** 4\ **Last updated:** [December 3, 2019, 7:28pm UTC](https://forum.opencyphal.org/t/which-libuavcan-branch-for-new-project/701 "2019-12-03T19:28:51Z")
Hi all, i was starting to integrate uavcan in my project. First i cloned the master branch but than i saw that the uavcan\_v1.0 is even more active in terms of commits. While reading here i found out that there is a gene… --- ## [Static deque for CANFD ISR buffer](https://forum.opencyphal.org/t/static-deque-for-canfd-isr-buffer/649)
**Author:** [@noxuz](https://forum.opencyphal.org/u/noxuz)\ **Replies:** 3\ **Last updated:** [October 18, 2019, 5:34pm UTC](https://forum.opencyphal.org/t/static-deque-for-canfd-isr-buffer/649 "2019-10-18T17:34:32Z")
Regarding the S32K driver layer for libuavcan, the current implementation uses an almost naive use of the deque STL for limiting the size of the RX queue as shown briefly next: if (RX\_ISRframeCount <= Frame\_Capactiy … --- ## [Libuavcan CubeMX FreeRTOS SystemWorkbenchForSTM32](https://forum.opencyphal.org/t/libuavcan-cubemx-freertos-systemworkbenchforstm32/430)
**Author:** [@raimondas](https://forum.opencyphal.org/u/raimondas)\ **Replies:** 28\ **Last updated:** [October 13, 2019, 3:37pm UTC](https://forum.opencyphal.org/t/libuavcan-cubemx-freertos-systemworkbenchforstm32/430 "2019-10-13T15:37:25Z")
Hello, I am trying to implement libuavcan on stm32f103tb6 (36 pins) mcu using cubemx generated project with freertos on system workbench IDE. Just for simplicity I am using generated project and IDE gives fast conversi… [Next page](https://forum.opencyphal.org/c/app/libcyphal/7.md?page=1)