Posted on July 17, 2013 at 16:33
For the MCO to generate 50 MHz you'd have to run the processor at a multiple of 50 MHz, I haven't looked at your board, you sure it doesn't have a crystal, or run from 25 MHz? Pretty sure the STM324x9I-EVAL does not support RMII.
GPIO_InitTypeDef GPIO_InitStructure;
/* Enable GPIOs clocks */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
/* Enable SYSCFG clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
/* Configure MCO (PA8) */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* Output HSE clock (25MHz) on MCO pin (PA8) to clock the PHY */
RCC_MCO1Config(RCC_MCO1Source_HSE, RCC_MCO1Div_1);
OR
/* Output PLL clock (50MHz from 150MHz) on MCO pin (PA8) to clock the PHY */
RCC_MCO1Config(RCC_MCO1Source_PLLCLK, RCC_MCO1Div_3); // !! CPU AT 150 MHz !!
