Nathan Gates

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10 years, 10 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
10 years, 10 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
10 years, 10 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!.