Nathan Gates

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9 years, 2 months ago.

MCO on nucleoF401

Hi

Im trying to access the MCO pin on the f401 nucleo so I can supply a clock signal to a OV7670 (without FIFO). Can I access and setup this pin as a clock output with mbed?

thanks

2 Answers

Peter Drescher
9 years, 2 months ago.

There is no direct function , you have to set up the IO and clock register to select and output the clock :

GPIO_InitTypeDef InitStruct;
    
HAL_RCC_MCOConfig(RCC_MCO1, RCC_MCO1SOURCE_PLLCLK, RCC_MCODIV_1);   // select PLLCLK as source


/*Configure GPIO pin to output clock signal at  PA8 */
  InitStruct.Pin = GPIO_PIN_8;
  InitStruct.Mode = GPIO_MODE_AF_PP;
  InitStruct.Pull = GPIO_NOPULL;
  InitStruct.Speed = GPIO_SPEED_HIGH;
  InitStruct.Alternate = GPIO_AF0_MCO;
  HAL_GPIO_Init(GPIOA, &InitStruct);

Accepted Answer

Thanks for the responses. This is what I was attempting but I was coping code verbatim from std peripheral library which wasn't being recognized. Thanks

posted by Nathan Gates 23 Jan 2015
David Lowe
9 years, 2 months ago.

Alternatively, the 8MHz xtal MCO of the ST-Link portion of the Nucleo is available on the underside of the board at SB16 (& SB50 if SB16 is bridged). That's assuming you haven't snapped off the ST-Link!.