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Need to know capability of STM32L073RZ board for generating sinusoidal 12.5 MHz burst signal.

Dineshkumar
Associate II

Hi All ,

I want to generate the following specification of the burst signal from the STM32L073RZ board  , need to know is that possible? Or else need your valuable suggestion whether it is possible from other STM32 boards?

 Parameters

Values /Settings

Waveform

Sine

Offset

0V

Phase

0 deg

Amplitude

 2mV

Frequency

12.5MHz

Burst Cycle #

 150

Trigger

 External

Load Impedance

 50 ohm

 

 

26 REPLIES 26
Michal Dudka
Senior III

Generaly not. But you can generate 12.5MHz squarewave and the filter out higher harmonics by low pass filter. 

 

Are you meaning ,do I need to integrate the LPF to convert the generated Square wave to Sinusoidal? Please confirm. Also  , can the amplitude of 2mV be achieved and load impedance of 50 ohms?

Michal Dudka
Senior III

It means only that you cannot generate 12.5MHz sine using embedded (and probably also external) DAC from L073. You can use multiple ways, like find some external DDS chip/module etc. And if your frequency is fixed, then probably some kind of active/passive first/second/third order LPF can be used. Depends on quality of sine you need. Amplitude of two mV into 50Ohm (only about 40uA) is probably OK with passive filters. But i am not an expert in "filter desing" - use simulator, or filter design calculator from AD, TI etc.

I am not sure how that "burst" should look like ... few periods, few milions of periods ? How fast it has to stop, how fast it has to start ? It is triggered by some kind of external signal, or not etc. Probably consider also use of some kind of RF switch at DDS output as gate to better control of burst. 

Burst cycle they mentioned was "150". The below figure illustrates the connection.

 

Dineshkumar_0-1708939849336.png

Instead of function  generator , I need to use the signal generator board like STM32  / DDS modules . Please guide me.

Try to some prototyping. Generate 12.5MHz from your STM by timer or MCO. Design some passive filter which attenuates your signal to about 2mV, connect it to your oscilloscope (with 50R termination) and verify. If need, try to change parameters of your filter. If you are not satisfied with results try way with DDS (and possibly RF siwtch, if your selected DDS isnt able to "keying").

ONadr.1
Senior III

It would require some clarification.

1. Is it necessary for the sine signal to start with a phase shift of 0 degrees?

2. Is the critical value 150 pulses?

3. What is the maximum acceptable value of the delay between the trigger pulse and the start of signal generation.

Hi , Please find my in-line response.

 

1. Is it necessary for the sine signal to start with a phase shift of 0 degrees?

Yes , it is necessary for the sine signal to start with a phase of 0 deg.

2. Is the critical value 150 pulses?

Not critical.

3. What is the maximum acceptable value of the delay between the trigger pulse and the start of signal generation

Not sure about the delay between trigger pulse , will check and come back.

 

Also , I tried to generate a 8 MHz sine wave using DAC , DMA and timer of  STM32 L073RZ board ,  the clock configuration for all the timer has been set to 32 MHz and prescalar and period have been set as "1" and samples kept as "100" , according to the formula for the signal frequency : 32 M / 1+1 = 8 MHz , but when I probe the PA4 pin in oscilloscope , I am getting only 40 KHz of sine wave . Could somebody point me , where I am wrong , below is the code generated.

 

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "math.h"
uint32_t sine_val[100];
 
#define PI 3.1415926
 
void get_sineval ()
{
for (int i=0; i<100; i++)
{
sine_val[i] = ((sin(i*2*PI/100) + 1)*(4096/2));
}
}
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
 
/* USER CODE END Includes */
 
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
 
/* USER CODE END PTD */
 
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
 
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
 
/* USER CODE END PM */
 
/* Private variables ---------------------------------------------------------*/
 DAC_HandleTypeDef hdac;
DMA_HandleTypeDef hdma_dac_ch1;
 
TIM_HandleTypeDef htim2;
 
/* USER CODE BEGIN PV */
 
/* USER CODE END PV */
 
/* 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_TIM2_Init(void);
/* USER CODE BEGIN PFP */
 
/* USER CODE END PFP */
 
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
 
/* USER CODE END 0 */
 
/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{
  /* USER CODE BEGIN 1 */
 
  /* USER CODE END 1 */
 
  /* MCU Configuration--------------------------------------------------------*/
 
  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();
 
  /* USER CODE BEGIN Init */
 
  /* USER CODE END Init */
 
  /* Configure the system clock */
  SystemClock_Config();
 
  /* USER CODE BEGIN SysInit */
 
  /* USER CODE END SysInit */
 
  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_DAC_Init();
  MX_TIM2_Init();
  /* USER CODE BEGIN 2 */
  HAL_TIM_Base_Start(&htim2);
 
  get_sineval();
 
HAL_DAC_Start_DMA(&hdac, DAC1_CHANNEL_1, sine_val, 100, DAC_ALIGN_12B_R);
  /* USER CODE END 2 */
 
  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
 
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}
 
/**
  * @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 RCC Oscillators according to the specified parameters
  * in the RCC_OscInitTypeDef structure.
  */
  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_6;
  RCC_OscInitStruct.PLL.PLLDIV = RCC_PLLDIV_3;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }
 
  /** Initializes the CPU, AHB and APB buses 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_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
 
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
  {
    Error_Handler();
  }
}
 
/**
  * @brief DAC Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_DAC_Init(void)
{
 
  /* USER CODE BEGIN DAC_Init 0 */
 
  /* USER CODE END DAC_Init 0 */
 
  DAC_ChannelConfTypeDef sConfig = {0};
 
  /* USER CODE BEGIN DAC_Init 1 */
 
  /* USER CODE END DAC_Init 1 */
 
  /** DAC Initialization
  */
  hdac.Instance = DAC;
  if (HAL_DAC_Init(&hdac) != HAL_OK)
  {
    Error_Handler();
  }
 
  /** DAC channel OUT1 config
  */
  sConfig.DAC_Trigger = DAC_TRIGGER_T2_TRGO;
  sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
  if (HAL_DAC_ConfigChannel(&hdac, &sConfig, DAC_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN DAC_Init 2 */
 
  /* USER CODE END DAC_Init 2 */
 
}
 
/**
  * @brief TIM2 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_TIM2_Init(void)
{
 
  /* USER CODE BEGIN TIM2_Init 0 */
 
  /* USER CODE END TIM2_Init 0 */
 
  TIM_ClockConfigTypeDef sClockSourceConfig = {0};
  TIM_MasterConfigTypeDef sMasterConfig = {0};
 
  /* USER CODE BEGIN TIM2_Init 1 */
 
  /* USER CODE END TIM2_Init 1 */
  htim2.Instance = TIM2;
  htim2.Init.Prescaler = 1;
  htim2.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim2.Init.Period = 1;
  htim2.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  htim2.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
  if (HAL_TIM_Base_Init(&htim2) != HAL_OK)
  {
    Error_Handler();
  }
  sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
  if (HAL_TIM_ConfigClockSource(&htim2, &sClockSourceConfig) != HAL_OK)
  {
    Error_Handler();
  }
  sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
  sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
  if (HAL_TIMEx_MasterConfigSynchronization(&htim2, &sMasterConfig) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN TIM2_Init 2 */
 
  /* USER CODE END TIM2_Init 2 */
 
}
 
/**
  * 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();
 
}
 
/* USER CODE BEGIN 4 */
 
/* USER CODE END 4 */
 
/**
  * @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 */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}
 
#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @PAram  file: pointer to the source file name
  * @PAram  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */