Hi, i am working on signal wave generation on the STM32L053 Discovery kit. I'd like to see the maximum frequency of signal generation (a sinus with 100 samples using DMA).
But the problem is : i cannot reach over ~20kHz, which is not even in the ultrasound domain.
The configuration of the peripherals must be wrong so, and I am using CubeMX to generate Low Layer code.
The system clock is PLLCLK at 32MHz (the maximum for AHB and APB1), and the DAC is triggered on the Timer6 trigger output.
I don't really understand the source of the problem. May someone can help me ? Thanks a lot !
Here is the code i used :
PS : the picture shows a problem i have when i change the SYSCLK frequency from under 4MHz to 8, 16 or 32 MHz. The sinus wave observed is at the right frequency but there are some timelaps where the potential is 0.
#include "main.h"
DAC_HandleTypeDef hdac;
DMA_HandleTypeDef hdma_dac_ch1;
TIM_HandleTypeDef htim6;
const uint8_t sinusValue100[100] = {144, 152, 160, 168, 175, 182, 190, 197, 203, 210,
216, 221, 227, 232, 236, 240, 244, 247, 250, 252,
254, 255, 255, 255, 255, 255, 254, 252, 250, 247,
244, 240, 236, 232, 227, 221, 216, 210, 203, 197,
190, 182, 175, 168, 160, 152, 144, 136, 128, 120,
112, 104, 96, 88, 81, 74, 66, 59, 53, 46,
40, 35, 29, 24, 20, 16, 12, 9, 6, 4,
2, 1, 0, 0, 0, 1, 2, 4, 6, 9,
12, 16, 20, 24, 29, 35, 40, 46, 53, 59,
66, 74, 81, 88, 96, 104, 112, 120, 128, 144};
const uint8_t signalResolution = 100;
const uint16_t outputFrequency = 5000;
const uint32_t CNT_FREQ = 32000000/4;
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_DAC_Init(void);
static void MX_TIM6_Init(void);
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* Configure the system clock */
SystemClock_Config();
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_DAC_Init();
MX_TIM6_Init();
/* Infinite loop */
while (1)
{
}
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/**Configure the main internal regulator output voltage
*/
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLLMUL_4;
RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_2;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV2;
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();
}
}
/**
* @brief DAC Initialization Function
* @param None
* @retval None
*/
static void MX_DAC_Init(void)
{
DAC_ChannelConfTypeDef sConfig = {0};
/**DAC Initialization
*/
hdac.Instance = DAC;
if (HAL_DAC_Init(&hdac) != HAL_OK)
{
Error_Handler();
}
/**DAC channel OUT1 config
*/
sConfig.DAC_Trigger = DAC_TRIGGER_T6_TRGO;
sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_DISABLE;
if (HAL_DAC_ConfigChannel(&hdac, &sConfig, DAC_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
if (HAL_DAC_Start_DMA(&hdac, DAC_CHANNEL_1, (uint32_t*)sinusValue100, 100, DAC_ALIGN_8B_R) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief TIM6 Initialization Function
* @param None
* @retval None
*/
static void MX_TIM6_Init(void)
{
TIM_MasterConfigTypeDef sMasterConfig = {0};
htim6.Instance = TIM6;
htim6.Init.Prescaler = 0;
htim6.Init.CounterMode = TIM_COUNTERMODE_UP;
htim6.Init.Period = 0xF;//CNT_FREQ/(signalResolution*outputFrequency);
htim6.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
if (HAL_TIM_Base_Init(&htim6) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim6, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
HAL_TIM_Base_Start(&htim6);
}
/**
* Enable DMA controller clock
*/
static void MX_DMA_Init(void)
{
/* DMA controller clock enable */
__HAL_RCC_DMA1_CLK_ENABLE();
/* DMA interrupt init */
/* DMA1_Channel2_3_IRQn interrupt configuration */
HAL_NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOA_CLK_ENABLE();
}
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
/* USER CODE END Error_Handler_Debug */
}
