STM32F4 Discovery Board

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This topic contains 5 replies, has 4 voices, and was last updated by  Anonymous 2 years, 11 months ago.

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  • #566

    Anonymous

    anyone managed to get his matrix working with the STM32F4 Discovery Board?
    I tried it with the example code here:

    https://github.com/C3MA/stm-ledstrip

    But I failed.

    After flashing I disconnected USB power, connected a powerful enough external power supply to the Discovery Board (PINS labeled 5V and GND) and to an RGB123 1×8 matrix I use for testing. Then I connected GPIO pin PC9 on the Discovery Board to the DIN port of the matrix.

    Did I do anything stupid hardware side?

    #570

    ohararp
    Keymaster

    Andi, I have found that code that works for the WS2811, rarely works with the WS2812B which has a tighter timing spec. It appears the library you reference is setup for the WS2811. I hope that helps.

    It looks like this might work http://eliaselectronics.com/driving-a-ws2812-rgb-led-with-an-stm32/ and was found using google: “STM32F4 WS2812”

    #573

    Anonymous

    Yes I know that code, it is for another STM32 controller not the F4 Discovery Board.

    The code I linked to has files and functions called ws2812_something, but mentions ws2811 in the README. Also some other code I found mixed ws2811 and ws2812 all over the place.

    Now I had a look at the data sheets and the problem seems to be indeed a timing issue, even ws2812 and ws2812b are different:

    WS2812:
    1 -> 0.7us high, 0.6 low = 1.30us
    0 -> 0.35us high, 0.8 low = 1.15us

    WS2812b:
    1 -> 0.8us high, 0.45 low = 1.25us
    0 -> 0.4us high, 0.85 low = 1.25us

    So I took some WS2811/WS2812 code and modified it, and I had the first LED lighten up sometimes. At least some progress.

    #578

    Anonymous

    Ok, success! 🙂

    Got the 1×8 working with the STM32F4 Discovery with some other code flying around in some github repository, it needed some fixes, but works now as intended.

    I still have to review which changes made the difference in the end, but if anyone needs help with the STM32F4 Discovery Board, I can help.

    I will run some more tests until I am confident enough to try my 8×8.

    #817

    Anonymous

    Now i definietly need help with that! Could you please post the working code somewhere?

    #1131

    Anonymous

    Nice, I am trying to to the same with an stm32 f4 discovery board and ws2812b led’s, any chance you can help out andi?

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