How can i use PA8 as MCO?

wuguobing · ‎2007-09-30

Posted on September 30, 2007 at 23:10

16-32micros · ‎2011-05-17

Posted on May 17, 2011 at 12:16

Dear wuguobing,

You can configure PA8 to MCO by simply calling these functions :

/* Configure GPIOA ------------------------------------------*/

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA , ENABLE);

/* Output HSE clock on MCO pin */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOA, &GPIO_InitStructure);

RCC_MCOConfig(RCC_MCO_HSE);

You can refer to the STM32 Firmware library using this link :

http://www.st.com/stonline/products/support/micro/files/um0427.zip

Then you can go to the RCC Example in this directory ''STM32F10xFWLib/FWLib/examples/RCC'' where you will find more details 😉

With best regards,

STOne-32

wuguobing · ‎2011-05-17

Posted on May 17, 2011 at 12:16

PA8 is a multi-function pin, it's AF can be USART1_CK, TIM1_CH1 or MCO, how can i config it to be MCO?

I can remap TIM1 to none, but USART1_CK can't be remapped!

wuguobing · ‎2011-05-17

Posted on May 17, 2011 at 12:16

Thanks a lot!

After reset, USART1_CK, TIM1_CH1 and MCO are disabled, to use PA8 as mco, just config MCO to work, and config PA8 to AF mode.:-D

Only one AF on the same pin can be enabled. But if two AF functions in output mode is enabled at same time, what would happen, stm32 will be destroyed?