STM32H753XIH6 port K alternate functions TIM1 and TIM8 not working

[serge_stm32dev]

SYS CONFIG

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IO Supplys = 3,3V, VCORE = 2,5V regulator used, FSystem = 200 MHz

Timer1 is configured for Output Compare CH1, sig 0.1MHz 50% duty expected (all necessary clk enabled)

Compare SIG is routed to PK1 via alternate conf 

__HAL_RCC_GPIOK_CLK_ENABLE();
GPIO_InitStruct.Pin = GPIO_PIN_1;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
GPIO_InitStruct.Alternate = GPIO_AF1_TIM1;
HAL_GPIO_Init(GPIOK, &GPIO_InitStruct);

After exec of this routine, PK1(J15) pin is in floating mode (1V because of 2Meg external pull-up to supply) .

Same signal routed to another port/same load with same routine is working properly 

Same problem and behavior with TIM8 witch can use the same PK1 pin

Note1 : if internal pull-up or pulldown added to pin conf, the pin is no longer floating, Hi(3,3V) for pull-up, Low(0,1V) for pulldown but still no signal output (input mode supposed) 

Note2 : The fact pull mode is reflected to pin when changed implies no addressing error. Output should be Hi or Low for compare output

Note3 : This same pin used as Output (no alternate function) works properly

Note4 : Same PK1 behavior when writing directly into GPIOK.AFRL register with emulator (floating when TIM1 (0x10) or TIM8 (0x30)). Normal output when 0...

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It seems the alternate functions may not be routed to port K but IDE software and doc say they can... 

Please HELP as this problem implies a very hight modification cost (10 layer board, BGA...)

[mƎALLEm · Accepted solution]

Hello @serge_stm32dev and welcome to the ST community,

1- In next time please use </> button to share the code. Your post will be edited to follow this community rule.

2- Check if the IO is not broken by simply toggling it using HAL_GPIO_TogglePin()

3- I also invite you to use CubeMx to configure and generate your code at least for tests.