Has someone started to implement the DSHOT on the PX4 (Nuttx) ? I’ve implemented the DSHOT protocol on Maple mini (Arduino IDE), but same Timer and DMA initialization sequence don’t work for me on Pixhawk2.

[image] DSHOT support Hi guys, is already anybody working on DSHOT support for PX4? Best regards Timo

@JulianOes , I know this two year old thread. I’m asking, because according to the roadmap, the dshot ability is planned to be released in June. So, the work has probably started, and i also can help.

Right that would be great. Let’s see if @dagar or @bkueng have pointers for you.

Hey @salex [image] salex: Has someone started to implement the DSHOT on the PX4 (Nuttx) ? No, not yet. But would be great if you want to look into that. [image] salex: I’ve implemented the DSHOT protocol on Maple mini (Arduino IDE), but same Timer and DMA initialization sequence don’t w…

I’m sorry, i can’t show my exact code, but it mostly based on this , with some timing adjustments it works with DSHOT150 on my Maple mini card. What is missing here, is building the DSHOT word with the CRC, which is quite simple. The most challenging part is hardware initialization, which is descri…

@david_s5 , @JulianOes This approach is different from one that used in Ardupilot/Betaflight, (which described in AN4776 of stm32 documentation). Using the code, i mentioned, on F4/F7 family actually requires to use specific DMA2 streams and one of the two advanced timers TIM1 or TIM8, which are ab…

@salex , @JulianOes , @bkueng Currently DMA is not used on SPI but will be coming in to master in the near future and that has to be factored in. Below are the Current assignments on the F4 for FMUv2-FMUv3 USART1 RX* DMA2,DMA_STREAM5,DMA_CHAN4 USART2 RX DMA1,DMA_STREAM5,DMA_CHAN4 USART3 RX …

@salex , @JulianOes , @bkueng I forgot one used by the px4io driver: USART6_TX* is DMA2,DMA_STREAM7,DMA_CHAN5

So it looks like Stream 4 is free. I’ll try to implement it in the way i showed in previous posts, when the DMA writes directly to GPIO’s BSRR, not to CCRx. I can use it with Timer1 Ch4 or Timer8 Ch3, because i need one of the advanced timers. Timer8 is used for HRT, can be switched with Timer5. …

[image] salex: I’ll try to implement it in the way i showed in previous posts, when the DMA writes directly to GPIO’s BSRR, not to CCRx. FMI there’s some discussion around that here: GPIO banging DShot by jflyper · Pull Request #7446 · betaflight/betaflight · GitHub . [image] salex: Regar…

DSHOT on PX4

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JulianOes March 26, 2019, 3:50pm 2

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DSHOT on PX4

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