STM32F746G-Disco problem with DAC

[Michal Steller]

Posted on May 30, 2017 at 13:45

Hi. I have STM32F746G-Disco board and problem with its analog out without DMA.

I am using STM32Cube_FW_F7_V1.6.0 withSW4STM32 toolchain and test it with simple LED.

I am a newcomer in STM, I am sure that i am missing something, this is my code:

// Scheme:

// LED R160 // +---|<|-----[==]------[ ] STM32F746G - arduino port A4 // | // | // +---------------------[ ] STM32F746G - arduino port GND

 #include 'stm32f7xx.h'
 #include 'stm32746g_discovery.h'
 #include 'stm32746g_discovery_lcd.h'
 #include <string.h>
 static void SystemClock_Config(void);
 static void LCD_Config(void);
 static void CPU_CACHE_Enable(void);
 DAC_HandleTypeDef DacHandle; /////////////////////////////////////////////////////////////////////////////// 
void HAL_DAC_MspInit(DAC_HandleTypeDef* hdac) 
{ 
 GPIO_InitTypeDef GPIO_InitStruct;
 __HAL_RCC_GPIOA_CLK_ENABLE();
 __HAL_RCC_DAC_CLK_ENABLE();
 GPIO_InitStruct.Pin = GPIO_PIN_4;
 GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
 GPIO_InitStruct.Pull = GPIO_NOPULL;
 HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
 }
 void HAL_DAC_MspDeInit(DAC_HandleTypeDef* hdac)
 { 
 __HAL_RCC_DAC_FORCE_RESET();
 __HAL_RCC_DAC_RELEASE_RESET();
 HAL_GPIO_DeInit(GPIOA, GPIO_PIN_4); 
}
 ///////////////////////////////////////////////////////////////////////////////
 int main(void) 
{
 unsigned int dac1Value = 0xF0FU, dac2Value;
 uint8_t outText[32];
 DAC_ChannelConfTypeDef sConfig;
 CPU_CACHE_Enable();
 HAL_Init();
 SystemClock_Config();
 LCD_Config();
 DacHandle.Instance = DAC;
 if (HAL_DAC_Init(&DacHandle) != HAL_OK) while(1){}
 sConfig.DAC_Trigger = DAC_TRIGGER_NONE;
 sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE;
 if (HAL_DAC_ConfigChannel(&DacHandle, &sConfig, DAC_CHANNEL_1) != HAL_OK) while(1){}
 if (HAL_DAC_Start(&DacHandle, DAC_CHANNEL_1) != HAL_OK) while(1){}
while(1)
 { 
 dac1Value+=0x10U; 
 if (dac1Value >= 0xFFF) dac1Value = 0U; 
 if (HAL_DAC_SetValue(&DacHandle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, dac1Value) != HAL_OK) while(1){} 
 dac2Value = HAL_DAC_GetValue(&DacHandle, DAC_CHANNEL_1); 
 sprintf((char*)outText, '%u %u', dac1Value, dac2Value); 
 BSP_LCD_Clear(LCD_COLOR_WHITE); 
 BSP_LCD_DisplayStringAt(10, 10, outText, LEFT_MODE); 
 HAL_Delay(50U); 
 } 
}
 /////////////////////////////////////////////////////////////////////////////// 
void SystemClock_Config(void) 
{
 RCC_ClkInitTypeDef RCC_ClkInitStruct;
 RCC_OscInitTypeDef RCC_OscInitStruct;
 HAL_StatusTypeDef ret = HAL_OK;
 /* Enable HSE Oscillator and activate PLL with HSE as source */
 RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
 RCC_OscInitStruct.HSEState = RCC_HSE_ON; 
 RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
 RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
 RCC_OscInitStruct.PLL.PLLM = 25;
 RCC_OscInitStruct.PLL.PLLN = 400;
 RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2; 
 RCC_OscInitStruct.PLL.PLLQ = 8;
 ret = HAL_RCC_OscConfig(&RCC_OscInitStruct); 
 if(ret != HAL_OK) { while(1) { ; } }
 /* Activate the OverDrive to reach the 200 MHz Frequency */ 
 ret = HAL_PWREx_EnableOverDrive(); 
 if(ret != HAL_OK) { while(1) { ; } } 
 /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */ 
 RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
 RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
 RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
 RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
 RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
 ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_6);
 if(ret != HAL_OK) { while(1) { ; } } 
} 
void LCD_Config(void) 
{ 
 BSP_LCD_Init();
 BSP_LCD_LayerDefaultInit(0, LCD_FB_START_ADDRESS); 
 BSP_LCD_LayerDefaultInit(1, LCD_FB_START_ADDRESS+(BSP_LCD_GetXSize() * BSP_LCD_GetYSize()*4)); 
 BSP_LCD_DisplayOn(); 
 BSP_LCD_SelectLayer(0);
 BSP_LCD_Clear(LCD_COLOR_WHITE);
 BSP_LCD_SelectLayer(1);
 BSP_LCD_Clear(LCD_COLOR_WHITE); 
 BSP_LCD_SetTransparency(0, 0);
 BSP_LCD_SetTransparency(1, 200);
 BSP_LCD_SetTextColor(LCD_COLOR_BLACK);
 BSP_LCD_SetFont(&Font24);
 } 
void CPU_CACHE_Enable(void) { SCB_EnableICache(); SCB_EnableDCache(); } 

#stm32f746g-discovery

[AvaTar]

Posted on May 30, 2017 at 13:53

What exactly is your problem ?

If you want to drive a LED with the onboard DAC, better check the datasheet (DAC characteristics).

There is a small load/impedance issue ...