@par Example Description
This example provides a short description of how to use the DAC peripheral to
generate several signals using DMA controller.
When the user presses the KEY push-button, DMA transfers the two selected
waveforms to the DAC.
For each press on KEY button, 2 signals has been selected and can be monitored on
the two DAC channels:
- Escalator waveform (Channel 1) and Sine waveForm (Channel 2).
- Noise waveform (Channel 1) and Triangle waveform (Channel 2).
@par Directory contents
- DAC/DAC_SignalsGeneration/stm32f4xx_conf.h Library Configuration file
- DAC/DAC_SignalsGeneration/stm32f4xx_it.c Interrupt handlers
- DAC/DAC_SignalsGeneration/stm32f4xx_it.h Interrupt handlers header file
- DAC/DAC_SignalsGeneration/main.c Main program
- DAC/DAC_SignalsGeneration/main.h Main program header file
- DAC/DAC_SignalsGeneration/system_stm32f4xx.c STM32F4xx system source file
1. main.c
/* Includes ------------------------------------------------------------------*/
#include "main.h"
DAC_InitTypeDef DAC_InitStructure;
const uint16_t aSine12bit[32] = {
2047, 2447, 2831, 3185, 3498, 3750, 3939, 4056, 4095, 4056,
3939, 3750, 3495, 3185, 2831, 2447, 2047, 1647, 1263, 909,
599, 344, 155, 38, 0, 38, 155, 344, 599, 909, 1263, 1647};
const uint8_t aEscalator8bit[6] = {0x0, 0x33, 0x66, 0x99, 0xCC, 0xFF};
__IO uint8_t ubSelectedWavesForm = 1;
__IO uint8_t ubKeyPressed = SET;
/* Private function prototypes -----------------------------------------------*/
static void TIM6_Config(void);
static void DAC_Ch1_EscalatorConfig(void);
static void DAC_Ch2_SineWaveConfig(void);
static void DAC_Ch1_NoiseConfig(void);
static void DAC_Ch2_TriangleConfig(void);
int main(void)
{
/*!< At this stage the microcontroller clock setting is already configured,
this is done through SystemInit() function which is called from startup
files (startup_stm32f40xx.s/startup_stm32f427x.s) before to branch to
application main.
To reconfigure the default setting of SystemInit() function, refer to
system_stm32f4xx.c file
*/
/* Preconfiguration before using DAC----------------------------------------*/
GPIO_InitTypeDef GPIO_InitStructure;
/* DMA1 clock enable */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
/* GPIOA clock enable (to be used with DAC) */
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
/* DAC Periph clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
/* DAC channel 1 & 2 (DAC_OUT1 = PA.4)(DAC_OUT2 = PA.5) configuration */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* TIM6 Configuration ------------------------------------------------------*/
TIM6_Config();
/* Configures Key Button */
STM_EVAL_PBInit(BUTTON_KEY, BUTTON_MODE_EXTI);
while (1)
{
/* If the Key is pressed */
if (ubKeyPressed != RESET)
{
DAC_DeInit();
/* select waves forms according to the Key Button status */
if (ubSelectedWavesForm == 1)
{
/* The sine wave and the escalator wave has been selected */
/* Escalator Wave generator ------------------------------------------*/
DAC_Ch1_EscalatorConfig();
/* Sine Wave generator -----------------------------------------------*/
DAC_Ch2_SineWaveConfig();
}
else
{
/* The triangle wave and the noise wave has been selected */
/* Noise Wave generator ----------------------------------------------*/
DAC_Ch1_NoiseConfig();
/* Triangle Wave generator -------------------------------------------*/
DAC_Ch2_TriangleConfig();
}
ubKeyPressed = RESET;
}
}
}
/**
* @brief TIM6 Configuration
* @note TIM6 configuration is based on APB1 frequency
* @note TIM6 Update event occurs each TIM6CLK/256
* @param None
* @retval None
*/
static void TIM6_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
/* TIM6 Periph clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
/* --------------------------------------------------------
TIM3 input clock (TIM6CLK) is set to 2 * APB1 clock (PCLK1),
since APB1 prescaler is different from 1.
TIM6CLK = 2 * PCLK1
TIM6CLK = HCLK / 2 = SystemCoreClock /2
TIM6 Update event occurs each TIM6CLK/256
Note:
SystemCoreClock variable holds HCLK frequency and is defined in system_stm32f4xx.c file.
Each time the core clock (HCLK) changes, user had to call SystemCoreClockUpdate()
function to update SystemCoreClock variable value. Otherwise, any configuration
based on this variable will be incorrect.
----------------------------------------------------------- */
/* Time base configuration */
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = 0xFF;
TIM_TimeBaseStructure.TIM_Prescaler = 0;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM6, &TIM_TimeBaseStructure);
/* TIM6 TRGO selection */
TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_Update);
/* TIM6 enable counter */
TIM_Cmd(TIM6, ENABLE);
}
/**
* @brief DAC Channel2 SineWave Configuration
* @param None
* @retval None
*/
static void DAC_Ch2_SineWaveConfig(void)
{
DMA_InitTypeDef DMA_InitStructure;
/* DAC channel2 Configuration */
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_2, &DAC_InitStructure);
/* DMA1_Stream6 channel7 configuration **************************************/
DMA_DeInit(DMA1_Stream6);
DMA_InitStructure.DMA_Channel = DMA_Channel_7;
DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)DAC_DHR12R2_ADDRESS;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&aSine12bit;
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
DMA_InitStructure.DMA_BufferSize = 32;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA1_Stream6, &DMA_InitStructure);
/* Enable DMA1_Stream6 */
DMA_Cmd(DMA1_Stream6, ENABLE);
/* Enable DAC Channel2 */
DAC_Cmd(DAC_Channel_2, ENABLE);
/* Enable DMA for DAC Channel2 */
DAC_DMACmd(DAC_Channel_2, ENABLE);
}
/**
* @brief DAC Channel1 Escalator Configuration
* @param None
* @retval None
*/
static void DAC_Ch1_EscalatorConfig(void)
{
DMA_InitTypeDef DMA_InitStructure;
/* DAC channel1 Configuration */
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_1, &DAC_InitStructure);
/* DMA1_Stream5 channel7 configuration **************************************/
DMA_DeInit(DMA1_Stream5);
DMA_InitStructure.DMA_Channel = DMA_Channel_7;
DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR8R1_ADDRESS;
DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&aEscalator8bit;
DMA_InitStructure.DMA_BufferSize = 6;
DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
DMA_InitStructure.DMA_Priority = DMA_Priority_High;
DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;
DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
DMA_Init(DMA1_Stream5, &DMA_InitStructure);
/* Enable DMA1_Stream5 */
DMA_Cmd(DMA1_Stream5, ENABLE);
/* Enable DAC Channel1 */
DAC_Cmd(DAC_Channel_1, ENABLE);
/* Enable DMA for DAC Channel1 */
DAC_DMACmd(DAC_Channel_1, ENABLE);
}
/**
* @brief DAC Channel2 Triangle Configuration
* @param None
* @retval None
*/
static void DAC_Ch2_TriangleConfig(void)
{
/* DAC channel2 Configuration */
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Triangle;
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_1023;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_2, &DAC_InitStructure);
/* Enable DAC Channel2 */
DAC_Cmd(DAC_Channel_2, ENABLE);
/* Set DAC channel2 DHR12RD register */
DAC_SetChannel2Data(DAC_Align_12b_R, 0x100);
}
/**
* @brief DAC Channel1 Noise Configuration
* @param None
* @retval None
*/
static void DAC_Ch1_NoiseConfig(void)
{
/* DAC channel1 Configuration */
DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Noise;
DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits10_0;
DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_1, &DAC_InitStructure);
/* Enable DAC Channel1 */
DAC_Cmd(DAC_Channel_1, ENABLE);
/* Set DAC Channel1 DHR12L register */
DAC_SetChannel1Data(DAC_Align_12b_L, 0x7FF0);
}
#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 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) */
/* Infinite loop */
while (1)
{
}
}
#endif
