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Visitor II
July 22, 2025
Solved

NUCLEO‑H755ZI TIM8 PWM: Channels 1–2 OK, Channels 3–4 Stuck at 0 V

  • July 22, 2025
  • 2 replies
  • 275 views

Hello,

 

I’m trying to drive LEDs using all four PWM channels of TIM8 on a NUCLEO‑H755ZI, but I’m running into this issue:

CH1 (PC6) and CH2 (PC7): When I measure with a multimeter, I see the expected voltage fluctuations/average corresponding to the configured frequency and duty cycle.

CH3 (PC8) and CH4 (PC9): I’ve removed the LEDs and measure the pins directly with a multimeter; they always read 0 V.

 

I’m attaching the project archive, which includes the CubeMX .ioc file, tim.c , gpio.c , the driver layer, and all HAL settings. I’d appreciate any suggestions or insights you might have. Thanks in advance!

    This topic has been closed for replies.
    Best answer by waclawek.jan

    Did you connect the SB9 and SB20 solder bridges?

    waclawekjan_0-1753174002348.png

     

    JW

    2 replies

    Super User
    July 22, 2025

    Did you connect the SB9 and SB20 solder bridges?

    waclawekjan_0-1753174002348.png

     

    JW

    durnaAuthor
    Visitor II
    July 22, 2025

    This change only affects the two relevant pins, right?

    Super User
    July 22, 2025

    Yes; keeping in mind that those two pins are still connected to SDMMC socket, see schematics and the Nucleo board's manual.

    JW