CAN bus emulation with FreeRTOS and Qt

Deck from Tallinn DevClub meetup

Transcript

1. CAN bus emulation with FreeRTOS and Qt Andrei Mukamolau, Dmitriy Stupak
2. Contents 1. Why 2. Prerequisites 3. FreeRTOS app 4. Qt app 5. Demo
3. Who we are • Automotive software development company • Develop and design apps • HMI • Android Automotive • Connected cars
4. Problem • App testing requires real data from the vehicle • It can be only obtained from the vehicle • We don’t often have needed vehicle available • Testing becomes expensive
5. Solution • Cheap CAN bus stand for development • Close to real life technologies • Test apps without vehicle
6. Hardware used in cars • Sensors • ECUs • Instrument cluster • Infotainment • CAN bus
7. CAN bus • Controlled Area Network • 2-way short range communication • Used in automotive and industrial apps • Simple at first glance • Fast • Robust
8. Software used in cars • Embedded soft for sensors • RTOS for ECUs • Embedded Linux for infotainment and instrument cluster • Android Automotive for infotainment
9. Software used in cars • Embedded soft for sensors • RTOS for ECUs • Embedded Linux for infotainment and instrument cluster • Android Automotive for infotainment
10. RTOS • Real Time Operating System • Scheduler runs tasks for a fixed amount of time • May not have all the features of standard OSes • Critical for safety-related systems
11. RTOSes • QNX • VxWorks • FreeRTOS
12. Software used in cars • Embedded soft for sensors • RTOS for ECUs • Embedded Linux for infotainment and instrument cluster • Android Automotive for infotainment
13. Embedded Linux • Regular Linux kernel, tuned for specific hardware • UI can be done in any way • Most popular is Qt
14. Tech stack • Arduino Uno with FreeRTOS app • Raspberry Pi with Qt app
15. FreeRTOS app
16. Hardware • Arduino Uno • CAN bus shield • Buttons • Wires • 10 kOhm resistor
17. Software • PlatformIO • C++ (Arduino) • FreeRTOS
18. Advantages • Arduino is cheap • Highly configurable • Can be extended and ported easily • FreeRTOS is flexible enough • Can be used backwards
19. Problems • Arduino Uno is not so powerful • FreeRTOS eats up memory if you’re not careful • Jitter
20. Qt app
21. What’s Qt • Cross-platform framework • Written in C++ • Signals and slots • Double licensing • Its own IDE - Qt Creator
22. Technologies/Tools
23. Qt Creator
24. Qt Creator - design editor
25. Connect can or vcan • Guide • Connect physical CAN HAT • Install the necessary modules • Set up it with commands • Install can-utils • Turn on the interface • Send frames with can-utils The same for vcan but without physical part
26. Cross-platform application Windows 10 Raspberry OS macOS
27. Hiccups • C++ errors are obscure • CAN loopback didn’t work • Qt libs on Raspberry are not available by default • Qt versions mismatch Win/Mac Qt 6.4.3 Raspberry OS 5.15.5
28. Demo app workflow • Click on the button on Arduino • Build CAN signal and send to Raspberry Pi via CAN wires • Receive CAN frame and process it • Visualize it in Qt application
29. Demo
30. Q&A
31. Thanks!