外接了25MHZ的晶振,如下配置,想使用PA8输出50MHZ的时钟,用示波器测PA8完全没有输出,同样的代码STM32F107是可以的,主要想把PA8用作RMII的参考时钟接DM9161以太网芯片:
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
RCC_PLL3Config(RCC_PLL3Mul_10);
/* Enable PLL3 */
RCC_PLL3Cmd(ENABLE);
/* Wait till PLL3 is ready */
while (RCC_GetFlagStatus(RCC_FLAG_PLL3RDY) == RESET)
{}
/* Get PLL3 clock on PA8 pin (MCO) */
RCC_MCOConfig(RCC_MCO_PLL3CLK);
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