2022-08-13 06:20 AM
I need to configure the system clock using registers for 48mhz without external crystal, I already have it configured and tested with stmcube ide manager, but I need to decrease the flash memory and ram, as they are critical.
i have this configuration step for 32mhz, but with external crystal:
/* 32MHz HSI PLL Configuration */
RCC->CR &= ~RCC_CR_PLLON; /* Keep PLL off */
RCC->CFGR &= ~RCC_CFGR_PLLSRC_Msk;
RCC->CFGR |= RCC_CFGR_PLLSRC_HSI_DIV2;
RCC->CFGR &= ~RCC_CFGR_PLLMUL_Msk;
RCC->CFGR |= RCC_CFGR_PLLMUL8;
RCC->CR |= RCC_CR_PLLON; /* Turn PLL on */
while ((RCC->CR & RCC_CR_PLLRDY) == 0); /* Wait for PLL to be ready */
RCC->CFGR &= ~RCC_CFGR_HPRE_Msk; /* Clear AHB resister */
RCC->CFGR |= RCC_CFGR_HPRE_DIV1; /* AHB Prescaler */
RCC->CFGR &= ~RCC_CFGR_PPRE_Msk; /* Clear APB1 resister */
RCC->CFGR |= RCC_CFGR_PPRE_DIV1; /* APB1 Prescaler */
RCC->CFGR &= ~RCC_CFGR_SW_Msk; /* Clear SW resister */
RCC->CFGR |= RCC_CFGR_SW_PLL; /* Set PLL as system clock */
find in the internet the step for configure clock is:
1._ ENABLE HSI and wait for the HSI to become Ready
2._ Set the POWER ENABLE CLOCK and VOLTAGE REGULATOR
3._Configure the FLASH PREFETCH and the LATENCY Related Settings
4._Configure the PRESCALARS HCLK, PCLK1
5._Configure the MAIN PLL
6._ Enable the PLL and wait for it to become ready
7._Select the Clock Source and wait for it to be set
THE STEP ONE I DON´T KNOW THIS IS RIGTH.
2022-08-13 07:26 AM
This makes 5 lines of code total
2022-08-15 09:33 AM
i am using the SystemInit() generated for excel macro
/** @addtogroup CMSIS
* @{
*/
/** @addtogroup stm32f0xx_system
* @{
*/
/** @addtogroup STM32F0xx_System_Private_Includes
* @{
*/
#include "stm32f0xx.h"
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_TypesDefinitions
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Defines
* @{
*/
#if !defined (HSE_VALUE)
#define HSE_VALUE ((uint32_t)8000000) /*!< Default value of the External oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSE_VALUE */
#if !defined (HSI_VALUE)
#define HSI_VALUE ((uint32_t)8000000) /*!< Default value of the Internal oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSI_VALUE */
#if !defined (HSI48_VALUE)
#define HSI48_VALUE ((uint32_t)48000000) /*!< Default value of the HSI48 Internal oscillator in Hz.
This value can be provided and adapted by the user application. */
#endif /* HSI48_VALUE */
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Macros
* @{
*/
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Variables
* @{
*/
/* This variable is updated in three ways:
1) by calling CMSIS function SystemCoreClockUpdate()
2) by calling HAL API function HAL_RCC_GetHCLKFreq()
3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
Note: If you use this function to configure the system clock; then there
is no need to call the 2 first functions listed above, since SystemCoreClock
variable is updated automatically.
*/
uint32_t SystemCoreClock = 8000000;
const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
const uint8_t APBPrescTable[8] = {0, 0, 0, 0, 1, 2, 3, 4};
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_FunctionPrototypes
* @{
*/
static void SetSysClock(void);
/**
* @}
*/
/** @addtogroup STM32F0xx_System_Private_Functions
* @{
*/
/**
* @brief Setup the microcontroller system
* @param None
* @retval None
*/
void SystemInit(void)
{
/* Set HSION bit */
RCC->CR |= (uint32_t)0x00000001;
/* Reset SW[1:0], HPRE[3:0], PPRE[2:0], ADCPRE and MCOSEL[2:0] bits */
RCC->CFGR &= (uint32_t)0xF8FFB80C;
/* Reset HSEON, CSSON and PLLON bits */
RCC->CR &= (uint32_t)0xFEF6FFFF;
/* Reset HSEBYP bit */
RCC->CR &= (uint32_t)0xFFFBFFFF;
/* Reset PLLSRC, PLLXTPRE and PLLMUL[3:0] bits */
RCC->CFGR &= (uint32_t)0xFFC0FFFF;
/* Reset PREDIV1[3:0] bits */
RCC->CFGR2 &= (uint32_t)0xFFFFFFF0;
/* Reset USARTSW[1:0], I2CSW, CECSW and ADCSW bits */
RCC->CFGR3 &= (uint32_t)0xFFFFFEAC;
/* Reset HSI14 bit */
RCC->CR2 &= (uint32_t)0xFFFFFFFE;
/* Disable all interrupts */
RCC->CIR = 0x00000000;
/* Configure the System clock frequency, AHB/APBx prescalers and Flash settings */
SetSysClock();
}
/**
* @brief Update SystemCoreClock variable according to Clock Register Values.
* The SystemCoreClock variable contains the core clock (HCLK), it can
* be used by the user application to setup the SysTick timer or configure
* other parameters.
*
* @note Each time the core clock (HCLK) changes, this function must be called
* to update SystemCoreClock variable value. Otherwise, any configuration
* based on this variable will be incorrect.
*
* @note - The system frequency computed by this function is not the real
* frequency in the chip. It is calculated based on the predefined
* constant and the selected clock source:
*
* - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
*
* - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
*
* - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**)
* or HSI_VALUE(*) multiplied/divided by the PLL factors.
*
* (*) HSI_VALUE is a constant defined in stm32f0xx_hal_conf.h file (default value
* 8 MHz) but the real value may vary depending on the variations
* in voltage and temperature.
*
* (**) HSE_VALUE is a constant defined in stm32f0xx_hal_conf.h file (its value
* depends on the application requirements), user has to ensure that HSE_VALUE
* is same as the real frequency of the crystal used. Otherwise, this function
* may have wrong result.
*
* - The result of this function could be not correct when using fractional
* value for HSE crystal.
*
* @param None
* @retval None
*/
void SystemCoreClockUpdate (void)
{
uint32_t tmp = 0, pllmull = 0, pllsource = 0, predivfactor = 0;
/* Get SYSCLK source -------------------------------------------------------*/
tmp = RCC->CFGR & RCC_CFGR_SWS;
switch (tmp)
{
case RCC_CFGR_SWS_HSI: /* HSI used as system clock */
SystemCoreClock = HSI_VALUE;
break;
case RCC_CFGR_SWS_HSE: /* HSE used as system clock */
SystemCoreClock = HSE_VALUE;
break;
case RCC_CFGR_SWS_PLL: /* PLL used as system clock */
/* Get PLL clock source and multiplication factor ----------------------*/
pllmull = RCC->CFGR & RCC_CFGR_PLLMUL;
pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
pllmull = ( pllmull >> 18) + 2;
predivfactor = (RCC->CFGR2 & RCC_CFGR2_PREDIV) + 1;
if (pllsource == RCC_CFGR_PLLSRC_HSE_PREDIV)
{
/* HSE used as PLL clock source : SystemCoreClock = HSE/PREDIV * PLLMUL */
SystemCoreClock = (HSE_VALUE/predivfactor) * pllmull;
}
#if defined(STM32F042x6) || defined(STM32F048xx) || defined(STM32F072xB) || defined(STM32F078xx) || defined(STM32F091xC) || defined(STM32F098xx)
else if (pllsource == RCC_CFGR_PLLSRC_HSI48_PREDIV)
{
/* HSI48 used as PLL clock source : SystemCoreClock = HSI48/PREDIV * PLLMUL */
SystemCoreClock = (HSI48_VALUE/predivfactor) * pllmull;
}
#endif /* STM32F042x6 || STM32F048xx || STM32F072xB || STM32F078xx || STM32F091xC || STM32F098xx */
else
{
#if defined(STM32F042x6) || defined(STM32F048xx) || defined(STM32F070x6) \
|| defined(STM32F078xx) || defined(STM32F071xB) || defined(STM32F072xB) \
|| defined(STM32F070xB) || defined(STM32F091xC) || defined(STM32F098xx) || defined(STM32F030xC)
/* HSI used as PLL clock source : SystemCoreClock = HSI/PREDIV * PLLMUL */
SystemCoreClock = (HSI_VALUE/predivfactor) * pllmull;
#else
/* HSI used as PLL clock source : SystemCoreClock = HSI/2 * PLLMUL */
SystemCoreClock = (HSI_VALUE >> 1) * pllmull;
#endif /* STM32F042x6 || STM32F048xx || STM32F070x6 ||
STM32F071xB || STM32F072xB || STM32F078xx || STM32F070xB ||
STM32F091xC || STM32F098xx || STM32F030xC */
}
break;
default: /* HSI used as system clock */
SystemCoreClock = HSI_VALUE;
break;
}
/* Compute HCLK clock frequency ----------------*/
/* Get HCLK prescaler */
tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
/* HCLK clock frequency */
SystemCoreClock >>= tmp;
}
static void SetSysClock(void)
{
/******************************************************************************/
/* PLL (clocked by HSI) used as System clock source */
/******************************************************************************/
/* At this stage the HSI is already enabled and used as System clock source */
/* SYSCLK, HCLK, PCLK configuration ----------------------------------------*/
/* Enable Prefetch Buffer and set Flash Latency */
FLASH->ACR = FLASH_ACR_PRFTBE | FLASH_ACR_LATENCY;
/* HCLK = SYSCLK / 1 */
RCC->CFGR |= (uint32_t)RCC_CFGR_HPRE_DIV1;
/* PCLK = HCLK / 1 */
RCC->CFGR |= (uint32_t)RCC_CFGR_PPRE_DIV1;
/* PLL configuration */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLXTPRE ));
RCC->CFGR |= (uint32_t)(RCC_CFGR_PLLSRC_HSI_DIV2 | RCC_CFGR_PLLXTPRE_Pos);
/* Enable PLL */
RCC->CR |= RCC_CR_PLLON;
/* Wait till PLL is ready */
while((RCC->CR & RCC_CR_PLLRDY) == 0)
{
}
/* Select PLL as system clock source */
RCC->CFGR &= (uint32_t)((uint32_t)~(RCC_CFGR_SW));
RCC->CFGR |= (uint32_t)RCC_CFGR_SW_PLL;
/* Wait till PLL is used as system clock source */
while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)RCC_CFGR_SWS_PLL)
{
}
}
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
the main code is:
i want view led blink in PA12, but i don´t view blink, the led is fixed on.
2022-08-15 09:35 AM
excuse me not resume the code,
#include <stdint.h>
#include <stm32f0xx.h>
/*
#if !defined(__SOFT_FP__) && defined(__ARM_FP)
#warning "FPU is not initialized, but the project is compiling for an FPU. Please initialize the FPU before use."
#endif
*/
void systme_clk()
{
/* 48 Mhz HSI PLL configuration */
/**************************************************************/
// HSI RC
// HSI PLL ON
// CONFIGURATE PLL MULTIPLEXOR
//
/*************************************************************/
/* 32MHz HSI PLL Configuration */
RCC->CR &= ~RCC_CR_PLLON; /* Keep PLL off */
RCC->CFGR &= ~RCC_CFGR_PLLSRC_Msk;
RCC->CFGR |= RCC_CFGR_PLLSRC_HSI_DIV2;
RCC->CFGR &= ~RCC_CFGR_PLLMUL_Msk;
RCC->CFGR |= RCC_CFGR_PLLMUL8;
RCC->CR |= RCC_CR_PLLON; /* Turn PLL on */
while ((RCC->CR & RCC_CR_PLLRDY) == 0); /* Wait for PLL to be ready */
RCC->CFGR &= ~RCC_CFGR_HPRE_Msk; /* Clear AHB resister */
RCC->CFGR |= RCC_CFGR_HPRE_DIV1; /* AHB Prescaler */
RCC->CFGR &= ~RCC_CFGR_PPRE_Msk; /* Clear APB1 resister */
RCC->CFGR |= RCC_CFGR_PPRE_DIV1; /* APB1 Prescaler */
RCC->CFGR &= ~RCC_CFGR_SW_Msk; /* Clear SW resister */
RCC->CFGR |= RCC_CFGR_SW_PLL; /* Set PLL as system clock */
}
void GPIO_Init(void)
{
RCC->AHBENR |= RCC_AHBENR_GPIOAEN; /* Enable GPIOA clock */
GPIOA->MODER |= (1<<24); // pin PA12(bits 11:10) as Output (01)
GPIOA->OTYPER &= ~(1<<12); // bit 12=0 --> Output push pull
GPIOA->OSPEEDR |= (1<<25); // Pin PA12 (bits 25:24) as Fast Speed (1:0)
GPIOA->PUPDR &= ~((1<<24) | (1<<25)); // Pin PA12 (bits 25:24) are 0:0 --> no pull up or pulldown
//RGB_DATA_GPIO_Port->MODER |= 0x02U << (RGB_DATA_Pin << 1); /* Alternate function mode */
//RGB_DATA_GPIO_Port->AFR[11] |= 5U << (RGB_DATA_Pin << 2); /* Alternate function (TIM16_CH1 AF5) */
//RGB_DATA_GPIO_Port->OSPEEDR |= 0b11 << (RGB_DATA_Pin << 1); /* output high-speed */
}
void Delay(uint32_t time)
{
while(time--);
}
int main(void)
{
//systme_clk();
SystemInit();
GPIO_Init();
/* Loop forever */
while(1)
{
//GPIOA->BSRR |= (1<<12); // Set the Pin PA12
GPIOA->ODR = 1<<12;
Delay (100000000); // random delay
// GPIOA->BSRR |= (1<<5) <<16; // Clear the Pin PA5
GPIOA->ODR &= ~(1<<12);
Delay (100000000); // random delay
}
}