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

[durna]

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!

[waclawek.jan · Accepted solution]

Did you connect the SB9 and SB20 solder bridges?

JW

[durna]

This change only affects the two relevant pins, right?

[waclawek.jan]

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

JW