how to allow the clock to be output onto the external MCO pin

yasamin · ‎2015-05-06

Posted on May 06, 2015 at 13:03

I want to have a sample of system clock at MCO pin of STM32F107RC micro controller.

I use dspin firmware library for driving stepper motor.

The on board crystal is 8MHz and system clock set to be 72MHz.

I add this code to ''dspin.c'':

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);

and I add the below line code in ''SetSysClockTo72()'' function at ''system_stm32f10x.c'' file.

RCC->CFGR &= (uint32_t)0xF6FFFFFF; //HSE clock selected as MCO source

But I don't have no clock output on this pin.

please guide me

thanks

yasamin

waclawek.jan · ‎2015-05-06

Posted on May 06, 2015 at 13:17

RCC->CFGR = (RCC->CFGR & (uint32_t)0xF0FFFFFF) | (uint32_t)0x08000000;

JW

yasamin · ‎2015-05-09

Posted on May 09, 2015 at 11:24

Hi

I add the below code

RCC->CFGR = (RCC->CFGR & (uint32_t)0xF0FFFFFF) | (uint32_t)0x08000000;

in ''SetSysClockTo72(void)'' function at ''system_stm32f10x.c''.

But I have the same problem yet!!!

please guide me to solve my problem.

thanks

stm32forum · ‎2015-05-09

Posted on May 09, 2015 at 12:47

MCO pin should be configured in alternate function mode.

yasamin · ‎2015-05-09

Posted on May 10, 2015 at 07:14

Hi

I configured MCO pin in alternate function mode by adding this code to ''dspin.c'':

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);

is it wrong?

and I add the below line code in ''SetSysClockTo72()'' function at ''system_stm32f10x.c'' file.

RCC->CFGR = (RCC->CFGR & (uint32_t)0xF0FFFFFF) | (uint32_t)0x08000000;

But I don't have no clock output on this pin.

yasamin

Tesla DeLorean · ‎2015-05-10

Posted on May 10, 2015 at 13:49

Evidently you're doing something wrong, or it would work..

{
GPIO_InitTypeDef GPIO_InitStructure;
/* Output HSE clock on MCO pin ---------------------------------------------*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
RCC_MCOConfig(RCC_MCO_HSE);
// RCC_MCOConfig(RCC_MCO_SYSCLK);
// If these work you'll need to check if you have PLL2 configured and running
}

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yasamin · ‎2015-05-11

Posted on May 11, 2015 at 11:21

thanks

it is solved

Ahmed.Waqar · ‎2015-05-12

Posted on May 12, 2015 at 13:25

I am using external interrupts. STM32F407 is not handling interrupt at speed of greater than 2MHz.

/* Includes ------------------------------------------------------------------*/

#include ''stm32f4xx.h''

#include ''stm32f4xx_syscfg.h''

#include ''stm32f4xx_rcc.h''

#include ''stm32f4xx_gpio.h''

#include ''stm32f4xx_exti.h''

#include ''misc.h''

EXTI_InitTypeDef EXTI_InitStructure;

void EXTILine0_Config(void);

void LEDInit(void);

void main(void)

{

LEDInit();

EXTILine0_Config();

EXTI_GenerateSWInterrupt(EXTI_Line0);

while (1)

{

}

void LEDInit()

{

GPIO_InitTypeDef GPIO_InitStructure;

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

/* Configure the GPIO_LED pin */

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;

GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;

GPIO_Init(GPIOD, &GPIO_InitStructure);

}

void EXTILine0_Config(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

/* Enable GPIOA clock */

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);

/* Enable SYSCFG clock */

RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);

/* Configure PA0 pin as input floating */

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;

GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;

GPIO_Init(GPIOA, &GPIO_InitStructure);

/* Connect EXTI Line0 to PA0 pin */

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);

/* Configure EXTI Line0 */

EXTI_InitStructure.EXTI_Line = EXTI_Line0;

EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;

EXTI_InitStructure.EXTI_LineCmd = ENABLE;

EXTI_Init(&EXTI_InitStructure);

/* Enable and set EXTI Line0 Interrupt to the lowest priority */

NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

void EXTI0_IRQHandler(void)

{

if (((EXTI->PR & EXTI_Line0) != (uint32_t)RESET) && ((EXTI->IMR & EXTI_Line0) != (uint32_t)RESET))

{

GPIOD->ODR ^= 0x8000;

EXTI->PR = 0x0001;

}

Please help me!

Amel NASRI · ‎2015-05-14

Posted on May 14, 2015 at 15:05

Hi Ahmed,

You have already submitted your question in another thread (

https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/How%20fast%20we%20can%20go%20with%20EXTI

).

Please avoid switching from one topic to another in the same thread.

Thanks & Best Regards

-Mayla-

To give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

Tesla DeLorean · ‎2015-05-14

Posted on May 14, 2015 at 16:55

I think he posted here first, as creating a ''New'' thread is far less apparent/obvious than replying to an older one.

Please just delete patently Off-Topic posts, or move them if the forum software permits that.

Thanks, -Clive

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