STM32 Spi CLock Problem

Posted on December 13, 2016 at 17:00

Hello! Im trying to comunicate via SPI with my AT25f4096 Flash Memory. Im using stm32f103 hal mode. It seems to be that the Clock is not working well. As you will see in the attachment, its not 'constant'. What possibly going wrong?

(sorry bout my osciloscope. Not good quality).

void SystemClock_Config(void)

{

RCC_OscInitTypeDef RCC_OscInitStruct;

RCC_ClkInitTypeDef RCC_ClkInitStruct;

RCC_PeriphCLKInitTypeDef PeriphClkInit;

RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_LSE;

RCC_OscInitStruct.HSEState = RCC_HSE_ON;

RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;

RCC_OscInitStruct.LSEState = RCC_LSE_ON;

RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;

RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;

RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL3;

if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)

{

Error_Handler();

}

RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK

|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;

RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSE;

RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;

RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;

RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)

{

Error_Handler();

}

PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_RTC|RCC_PERIPHCLK_ADC

|RCC_PERIPHCLK_USB;

PeriphClkInit.RTCClockSelection = RCC_RTCCLKSOURCE_LSE;

PeriphClkInit.AdcClockSelection = RCC_ADCPCLK2_DIV4;

PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLL;

if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)

{

Error_Handler();

}

HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

/* SysTick_IRQn interrupt configuration */

HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);

}

/* SPI2 init function */

static void MX_SPI2_Init(void)

{

hspi2.Instance = SPI2;

hspi2.Init.Mode = SPI_MODE_MASTER;

hspi2.Init.Direction = SPI_DIRECTION_2LINES;

hspi2.Init.DataSize = SPI_DATASIZE_8BIT;

hspi2.Init.CLKPolarity = SPI_POLARITY_HIGH;

hspi2.Init.CLKPhase = SPI_PHASE_1EDGE;

hspi2.Init.NSS = SPI_NSS_SOFT;

hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_64;

hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;

hspi2.Init.TIMode = SPI_TIMODE_DISABLE;

hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;

hspi2.Init.CRCPolynomial = 10;

if (HAL_SPI_Init(&hspi2) != HAL_OK)

{

Error_Handler();

}

}