第18章 DAC介绍及应用
第十八章 DAC介绍及应用
1. DAC简介
TM32F407 的 DAC 模块（数字/模拟转换模块） 是 12 位数字输入，电压输出型的 DAC。DAC 可以配置为 8 位或 12 位模式，也可以与 DMA 控制器配合使用。 DAC 工作在 12 位模式时，数据可以设置成左对齐或右对齐。 DAC 模块有 2 个输出通道，每个通道都有单独的转换器。在双 DAC 模式下， 2 个通道可以独立地进行转换，也可以同时进行转换并同步地更新 2 个通道的输出。 DAC 可以通过引脚输入参考电压 Vref+（通 ADC 共用） 以获得更精确的转换结果。
图中 VDDA 和 VSSA 为 DAC 模块模拟部分的供电，而 VREF+则是 DAC 模块的参考电压。DAC_OUT1/2 就是 DAC 的两个输出通道了（对应 PA4 或者 PA5 引脚）。 ADC 的这些输入/输出引脚信息如下表所示：
2. DAC应用示例
2.1 DAC输出指定电压
2.1.1 DAC初始化
void dac_init(uint8_t outx)
{
__HAL_RCC_DAC_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
GPIO_InitTypeDef GPIO_InitStruct;
GPIO_InitStruct.Pin = (outx==1)? GPIO_PIN_4 : GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
dac_handle.Instance = DAC;
HAL_DAC_Init(&dac_handle);
DAC_ChannelConfTypeDef dac_ch_handle;
dac_ch_handle.DAC_Trigger = DAC_TRIGGER_NONE;
dac_ch_handle.DAC_OutputBuffer = DAC_OUTPUTBUFFER_DISABLE;
switch (outx)
{
case 1:
HAL_DAC_ConfigChannel(&dac_handle, &dac_ch_handle, DAC_CHANNEL_1);
HAL_DAC_Start(&dac_handle, DAC_CHANNEL_1);
break;
case 2:
HAL_DAC_ConfigChannel(&dac_handle, &dac_ch_handle, DAC_CHANNEL_2);
HAL_DAC_Start(&dac_handle, DAC_CHANNEL_2);
break;
default:
break;
}
}
2.1.2 DAC设置电压
// 设置输出通道电压
void dac_set_voltage(uint8_t outx, uint16_t voltage)
{
double temp = voltage;
temp /= 1000;
temp = temp*4095/3.3;
if(temp > 4095)
temp = 4095;
if(outx)
{
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, temp); // 设置DAC输出值
}
else
{
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_2, DAC_ALIGN_12B_R, temp);
}
}
2.1.3 主函数测试
#include "bsp_init.h"
#include "stdio.h"
#include "adc.h"
#include "dac.h"
extern DAC_HandleTypeDef dac_handle;
int main(void)
{
uint16_t adc_value;
float temp;
uint8_t i =0;
uint16_t dac_value = 0;
uint8_t key_value = 0;
bsp_init();
adc_init();
dac_init(1); // 初始化DAC1_OUT1通道 1:DAC_OUT_1-PA4 2:DAC_OUT_2-PA5
LCD_ShowString(30,50,200,16,16,"STM32F4 DAC Test");
LCD_ShowString(30,110,200,16,16,"WK_UP:+ KEY1:-");
LCD_ShowString(30,130,200,16,16,"DAC VAL:");
LCD_ShowString(30,150,200,16,16,"DAC VOL:0.000V");
LCD_ShowString(30,170,200,16,16,"ADC VOL:0.000V");
while(1)
{
i++;
key_value = key_scan(0);
if(key_value == WKUP_Press)
{
if(dac_value < 4095)
{
dac_value += 200;
}
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, dac_value);
}
else if(key_value == KEY1_Press)
{
if(dac_value > 0)
{
dac_value -= 200;
}
else
{
dac_value = 0;
}
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, dac_value);
}
if(i == 0 || key_value == KEY1_Press || key_value == WKUP_Press) // WKUP/KEY1按下了,或者定时时间到了
{
adc_value = HAL_DAC_GetValue(&dac_handle, DAC_CHANNEL_1); // 获取DAC输出值
LCD_ShowxNum(94,130,adc_value,4,16,0);
temp = (float)adc_value*(3.3/4095); // 计算ADC电压值
adc_value = temp;
LCD_ShowxNum(94,150,temp,1,16,0); // 显示电压整数值
temp -= adc_value;
temp *= 1000;
LCD_ShowxNum(110,150,temp,3,16,0x80);
adc_value = adc_get_result_average(ADC_CHANNEL_5, 20); // 获取ADC电压值
temp = (float)adc_value*(3.3/4095); // 计算ADC电压值
adc_value = temp;
LCD_ShowxNum(94,170,temp,1,16,0); // 显示电压整数值
temp -= adc_value;
temp *= 1000;
LCD_ShowxNum(110,170,temp,3,16,0x80);
LED_TOGGLE(LED0_GPIO_Pin);
i = 0;
}
delay_ms(10);
}
}
2.2 PWM模拟DAC
2.2.1 定时器配置
#include "dac.h"
// 定时器PWM模拟DAC
TIM_HandleTypeDef tim_handle;
TIM_OC_InitTypeDef tim_oc_init;
void pwmdac_init(uint16_t arr, uint16_t psc)
{
tim_handle.Instance = TIM9;
tim_handle.Init.Prescaler = psc;
tim_handle.Init.Period = arr;
tim_handle.Init.CounterMode = TIM_COUNTERMODE_UP;
HAL_TIM_PWM_Init(&tim_handle);
tim_oc_init.OCMode = TIM_OCMODE_PWM1;
tim_oc_init.Pulse = arr/2;
tim_oc_init.OCPolarity = TIM_OCPOLARITY_HIGH;
HAL_TIM_PWM_ConfigChannel(&tim_handle, &tim_oc_init, TIM_CHANNEL_2);
HAL_TIM_PWM_Start(&tim_handle, TIM_CHANNEL_2);
}
void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef *htim)
{
GPIO_InitTypeDef gpio_init;
if(htim->Instance == TIM9)
{
__HAL_RCC_TIM9_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
gpio_init.Pin = GPIO_PIN_3;
gpio_init.Mode = GPIO_MODE_AF_PP;
gpio_init.Pull = GPIO_PULLUP;
gpio_init.Speed = GPIO_SPEED_FREQ_HIGH;
gpio_init.Alternate = GPIO_AF3_TIM9;
HAL_GPIO_Init(GPIOA, &gpio_init);
}
}
2.2.2 设置输出电压
void pwmdac_set_value(uint16_t value)
{
float temp = value;
temp /= 100;
temp = temp*256/3.3f;
__HAL_TIM_SET_COMPARE(&tim_handle, TIM_CHANNEL_4, temp);
}
2.2.3 主函数测试
#include "bsp_init.h"
#include "stdio.h"
#include "adc.h"
#include "dac.h"
extern TIM_HandleTypeDef tim_handle;
int main(void)
{
uint16_t adc_value = 0;
float temp;
uint8_t i = 0;
uint8_t key_value = 0;
uint16_t dac_value;
bsp_init();
adc_init();
pwmdac_init(256-1,0); // PWM DAC初始化,Fpwm = 84 / 256 =328.125Khz
LCD_ShowString(30,130,200,16,16,"PWM VAL:");
LCD_ShowString(30,150,200,16,16,"DAC VOL:0.000V");
LCD_ShowString(30,170,200,16,16,"ADC VAL:0.000V");
__HAL_TIM_SET_COMPARE(&tim_handle, TIM_CHANNEL_2, dac_value);
while(1)
{
i++;
key_value = key_scan(0);
if(key_value == WKUP_Press)
{
if(dac_value < 250)
{
dac_value += 10;
}
__HAL_TIM_SET_COMPARE(&tim_handle, TIM_CHANNEL_2, dac_value);
}
else if(key_value == KEY1_Press)
{
if(dac_value > 10)
{
dac_value -= 10;
}
else
{
dac_value = 0;
}
__HAL_TIM_SET_COMPARE(&tim_handle, TIM_CHANNEL_2, dac_value);
}
if(i == 10||key_value == WKUP_Press||key_value == KEY1_Press)
{
/* DAC值读取计算 */
adc_value = __HAL_TIM_GET_COMPARE(&tim_handle, TIM_CHANNEL_2);
LCD_ShowxNum(94,130,adc_value,3,16,0);
temp = (float)adc_value*(3.3/256);
adc_value = temp;
LCD_ShowxNum(94,150,temp,1,16,0);
temp -= adc_value;
temp *= 1000;
LCD_ShowxNum(110,150,temp,3,16,0x80);
/* ADC值读取计算 */
adc_value = adc_get_result_average(ADC_CHANNEL_5, 10);
temp = (float)adc_value*(3.3/4096);
adc_value = temp;
LCD_ShowxNum(94,170,temp,1,16,0);
temp -= adc_value;
temp *= 1000;
LCD_ShowxNum(110,170,temp,3,16,0x80);
LED_TOGGLE(LED0_GPIO_Pin);
i = 0;
}
delay_ms(5);
}
}
2.3 DAC输出三角波
2.3.1 DAC初始化
#include "dac.h"
#include "delay.h"
DAC_HandleTypeDef dac_handle;
void dac_init(uint8_t outx)
{
__HAL_RCC_DAC_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
GPIO_InitTypeDef GPIO_InitStruct;
GPIO_InitStruct.Pin = (outx==1)? GPIO_PIN_4 : GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
dac_handle.Instance = DAC;
HAL_DAC_Init(&dac_handle);
DAC_ChannelConfTypeDef dac_ch_handle;
dac_ch_handle.DAC_Trigger = DAC_TRIGGER_NONE;
dac_ch_handle.DAC_OutputBuffer = DAC_OUTPUTBUFFER_DISABLE;
switch (outx)
{
case 1:
HAL_DAC_ConfigChannel(&dac_handle, &dac_ch_handle, DAC_CHANNEL_1);
HAL_DAC_Start(&dac_handle, DAC_CHANNEL_1);
break;
case 2:
HAL_DAC_ConfigChannel(&dac_handle, &dac_ch_handle, DAC_CHANNEL_2);
HAL_DAC_Start(&dac_handle, DAC_CHANNEL_2);
break;
default:
break;
}
}
// 设置输出通道电压
void dac_set_voltage(uint8_t outx, uint16_t voltage)
{
double temp = voltage;
temp /= 1000;
temp = temp*4095/3.3;
if(temp > 4095)
temp = 4095;
if(outx)
{
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, temp); // 设置DAC输出值
}
else
{
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_2, DAC_ALIGN_12B_R, temp);
}
}
2.3.2 输出三角波
/**
* @brief 设置DAC_OUT1输出三角波
* @note 输出频率 ≈ 1000 / (dt * samples) Khz, 不过在dt较小的时候,比如小于5us时, 由于delay_us
* 本身就不准了(调用函数,计算等都需要时间,延时很小的时候,这些时间会影响到延时), 频率会偏小.
*
* @param maxval : 最大值(0 < maxval < 4096), (maxval + 1)必须大于等于samples/2
* @param dt : 每个采样点的延时时间(单位: us)
* @param samples: 采样点的个数, samples必须小于等于(maxval + 1) * 2 , 且maxval不能等于0
* @param n : 输出波形个数,0~65535
*
* @retval 无
*/
void dac_triangular_wave(uint16_t maxval, uint16_t dt, uint16_t samples, uint16_t n)
{
uint16_t i, j;
float incval; // 递增量
float Curval; // 当前值
if((maxval + 1) <= samples) return ; // 数据不合法
incval = (maxval + 1) / (samples / 2); // 计算递增量
for(j = 0; j < n; j++)
{
Curval = 0;
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, Curval); // 先输出0
for(i = 0; i < (samples / 2); i++) // 输出上升沿
{
Curval += incval; // 新的输出值
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, Curval);
delay_us(dt);
}
for(i = 0; i < (samples / 2); i++) // 输出下降沿
{
Curval -= incval; // 新的输出值
HAL_DAC_SetValue(&dac_handle, DAC_CHANNEL_1, DAC_ALIGN_12B_R, Curval);
delay_us(dt);
}
}
}
2.3.3 主函数测试
#include "bsp_init.h"
#include "stdio.h"
#include "adc.h"
#include "dac.h"
extern DAC_HandleTypeDef dac_handle;
int main(void)
{
uint8_t i = 0;
uint8_t key_value = 0;
bsp_init();
adc_init();
dac_init(1); // 初始化DAC1_OUT1通道 1:DAC_OUT_1-PA4 2:DAC_OUT_2-PA5
LCD_ShowString(30,50,200,16,16,"STM32F4 DAC Triangular Test");
LCD_ShowString(30,110,200,16,16,"KEY0:Wave1 WKUP:Wave2");
LCD_ShowString(30,130,200,16,16,"DAC None");
while(1)
{
i++;
key_value = key_scan(0);
if(key_value == KEY0_Press)
{
LCD_ShowString(30,130,200,16,16,"DAC Wave1");
dac_triangular_wave(4095,5,2000,100); /* 幅值4095, 采样点间隔5us, 2000个采样点, 100个波形 */
LCD_ShowString(30,130,200,16,16,"DAC None ");
}
else if(key_value == WKUP_Press)
{
LCD_ShowString(30,130,200,16,16,"DAC Wave2");
dac_triangular_wave(4095,500,20,100); /* 幅值4095, 采样点间隔500us, 20个采样点, 100个波形 */
LCD_ShowString(30,130,200,16,16,"DAC None ");
}
if(i == 10)
{
LED_TOGGLE(LED0_GPIO_Pin);
i = 0;
}
delay_ms(10);
}
}
2.4 DAC输出正弦波
2.4.1 DAC-DMA初始化
void dac_dma_init(uint8_t outx)
{
DAC_ChannelConfTypeDef dac_ch_handle;
GPIO_InitTypeDef GPIO_InitStruct;
__HAL_RCC_GPIOA_CLK_ENABLE();
__HAL_RCC_DAC_CLK_ENABLE();
__HAL_RCC_DMA1_CLK_ENABLE();
GPIO_InitStruct.Pin = (outx==1)? GPIO_PIN_4 : GPIO_PIN_5;
GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
GPIO_InitStruct.Pull = GPIO_NOPULL;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
dac_handle.Instance = DAC;
HAL_DAC_Init(&dac_handle);
dac_dma_handle.Instance = (outx==1)?DMA1_Stream5:DMA1_Stream6; // DMA1_Stream5/6
dac_dma_handle.Init.Channel = DMA_CHANNEL_7;
dac_dma_handle.Init.Direction = DMA_MEMORY_TO_PERIPH; // 存储器到外设
dac_dma_handle.Init.PeriphInc = DMA_PINC_DISABLE; // 外设地址不增长
dac_dma_handle.Init.MemInc = DMA_MINC_ENABLE; // 存储器地址增长
dac_dma_handle.Init.PeriphDataAlignment = DMA_PDATAALIGN_HALFWORD;
dac_dma_handle.Init.MemDataAlignment = DMA_MDATAALIGN_HALFWORD;
dac_dma_handle.Init.Mode = DMA_CIRCULAR; // 循环模式
dac_dma_handle.Init.Priority = DMA_PRIORITY_MEDIUM;
dac_dma_handle.Init.FIFOMode = DMA_FIFOMODE_DISABLE; // 禁用FIFO
HAL_DMA_Init(&dac_dma_handle);
__HAL_LINKDMA(&dac_handle, DMA_Handle1, dac_dma_handle); // 链接DMA
dac_ch_handle.DAC_Trigger = DAC_TRIGGER_T7_TRGO; // 定时器7触发
dac_ch_handle.DAC_OutputBuffer = DAC_OUTPUTBUFFER_ENABLE; // 使能输出缓冲
HAL_DAC_ConfigChannel(&dac_handle, &dac_ch_handle, DAC_CHANNEL_1); // 配置通道1
}
2.4.2 使能波形输出
/**
* @brief DAC DMA使能波形输出
* @note TIM7的输入时钟频率(f)来自APB1, f = 42 * 2 = 84Mhz.
* DAC触发频率 ftrgo = f / ((psc + 1) * (arr + 1))
* 波形频率 = ftrgo / ndtr;
* @param outx : DAC通道1/2
* @param ndtr : DMA通道单次传输数据量
* @param arr : TIM7的自动重装载值
* @param psc : TIM7的分频系数
* @retval 无
*/
void dac_dma_wave_enable(uint8_t outx, uint16_t ndtr, uint16_t arr, uint16_t psc)
{
TIM_HandleTypeDef tim7_handle = {0};
TIM_MasterConfigTypeDef master_config = {0};
__HAL_RCC_TIM7_CLK_ENABLE();
tim7_handle.Instance = TIM7;
tim7_handle.Init.Prescaler = psc;
tim7_handle.Init.CounterMode = TIM_COUNTERMODE_UP;
tim7_handle.Init.Period = arr;
tim7_handle.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_ENABLE;
HAL_TIM_Base_Init(&tim7_handle); // TIM7初始化
master_config.MasterOutputTrigger = TIM_TRGO_UPDATE; // 定时器7更新触发
master_config.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE; // 禁止同步模式
HAL_TIMEx_MasterConfigSynchronization(&tim7_handle, &master_config); // 配置TIM7 TRGO
HAL_TIM_Base_Start(&tim7_handle);
HAL_DAC_Stop_DMA(&dac_handle, (outx == 1) ? DAC_CHANNEL_1 : DAC_CHANNEL_2); // 先停止之前的传输
HAL_DAC_Start_DMA(&dac_handle, (outx == 1) ? DAC_CHANNEL_1 : DAC_CHANNEL_2, (uint32_t*)dac_sin_buf, ndtr, DAC_ALIGN_12B_R); // 启动DMA传输
}
2.4.3 产生正弦波函序列
/**
* @brief 产生正弦波函序列
* @note 需保证 : maxval > samples/2
* @param maxval : 最大值(0 < maxval < 2048)
* @param samples: 采样点的个数
* @retval 无
*/
void dac_creat_sin_buf(uint16_t maxval, uint16_t samples)
{
uint8_t i;
float inc = (2 * 3.1415962) / samples; // 计算增量（一个周期DAC_SIN_BUF个点）
float outdata = 0;
for (i = 0; i < samples; i++)
{
outdata = maxval * (1 + sin(inc * i)); // 计算以dots个点为周期的每个点的值，放大maxval倍，并偏移到正数区域
if (outdata > 4095)
outdata = 4095;
//printf("%f\r\n", outdata);
dac_sin_buf[i] = outdata;
}
}
// 设置正弦波输出参数
void dac_dma_sin_set(uint16_t arr, uint16_t psc)
{
dac_dma_wave_enable(1,100,arr,psc);
}
2.4.4 主函数测试
int main(void)
{
uint8_t i = 0;
uint8_t key_value = 0;
float temp = 0;
uint16_t adc_value = 0;
bsp_init();
adc_init();
dac_dma_init(1);
LCD_ShowString(30,50,200,16,16,"STM32F4 DAC SineWave");
LCD_ShowString(30,110,200,16,16,"KEY0:3KHZ KEY1:30KHZ");
LCD_ShowString(30,130,200,16,16,"DAC VAL:");
LCD_ShowString(30,150,200,16,16,"DAC VOL:0.000V");
LCD_ShowString(30,170,200,16,16,"ADC VAL:0.000V");
dac_creat_sin_buf(2048,100);
dac_dma_wave_enable(1,100,10-1,84-1);
while(1)
{
i++;
key_value = key_scan(0);
if(key_value == KEY0_Press)
{
dac_creat_sin_buf(2048,100);
dac_dma_wave_enable(1,100,10-1,28-1);/* 300Khz触发频率, 100个点, 可以得到最高3KHz的正弦波. */
}
else if(key_value == KEY1_Press)
{
dac_creat_sin_buf(2048,10);
dac_dma_wave_enable(1,10,10-1,28-1);/* 300Khz触发频率, 10个点, 可以得到最高30KHz的正弦波. */
}
// 显示DAC输出值
adc_value = DAC1->DHR12R1;
LCD_ShowxNum(94,130,adc_value,4,16,0);
temp = (float)adc_value*(3.3/4095);
adc_value = temp;
LCD_ShowxNum(94,150,temp,1,16,0);
temp -= adc_value;
temp *= 1000;
LCD_ShowxNum(110,150,temp,3,16,0x80);
// 显示ADC输入值
adc_value = adc_get_result_average(ADC_CHANNEL_5 ,20);
temp = (float)adc_value*(3.3/4095);
adc_value = temp;
LCD_ShowxNum(94,170,temp,1,16,0);
temp -= adc_value;
temp *= 1000;
LCD_ShowxNum(110,170,temp,3,16,0x80);
if(i == 10)
{
LED_TOGGLE(LED0_GPIO_Pin);
i = 0;
}
delay_ms(5);
}
}
3. DAC常见函数（HAL库）
3.1 DAC 初始化与配置
3.1.1 HAL_DAC_Init()
函数原型:
HAL_StatusTypeDef HAL_DAC_Init(DAC_HandleTypeDef *hdac)
参数:
hdac: DAC 句柄指针
配置结构体:
typedef struct {
DAC_TypeDef *Instance; // DAC实例 (DAC)
__IO HAL_DAC_StateTypeDef State; // DAC状态
HAL_LockTypeDef Lock; // 锁定对象
} DAC_HandleTypeDef;
功能: 初始化 DAC 外设
示例配置:
DAC_HandleTypeDef hdac1;
void DAC_Init(void) {
__HAL_RCC_DAC_CLK_ENABLE();
hdac1.Instance = DAC;
if (HAL_DAC_Init(&hdac1) != HAL_OK) {
Error_Handler();
}
}
3.2 DAC 通道配置
3.2.1 HAL_DAC_ConfigChannel()
函数原型:
HAL_StatusTypeDef HAL_DAC_ConfigChannel(
DAC_HandleTypeDef *hdac,
DAC_ChannelConfTypeDef *sConfig,
uint32_t Channel)
参数:
-
Channel: 通道选择:DAC_CHANNEL_1或DAC_CHANNEL_2 -
sConfig: 通道配置结构体指针
通道配置结构体:
typedef struct {
uint32_t DAC_Trigger; // 触发源:
// DAC_TRIGGER_NONE (软件触发)
// DAC_TRIGGER_T2_TRGO
// DAC_TRIGGER_T4_TRGO
// DAC_TRIGGER_T5_TRGO
// DAC_TRIGGER_T6_TRGO
// DAC_TRIGGER_T7_TRGO
// DAC_TRIGGER_T8_TRGO
// DAC_TRIGGER_EXT_IT9
// DAC_TRIGGER_SOFTWARE
uint32_t DAC_OutputBuffer; // 输出缓冲:
// DAC_OUTPUTBUFFER_ENABLE/DISABLE
uint32_t DAC_ConnectOnChipPeripheral; // 保留参数 (设为0)
uint32_t DAC_UserTrimming; // 修整模式:
// DAC_TRIMMING_FACTORY (出厂修整)
// DAC_TRIMMING_USER (用户修整)
} DAC_ChannelConfTypeDef;
示例配置:
DAC_ChannelConfTypeDef sConfig = {0};
// 配置DAC通道1
sConfig.DAC_Trigger = DAC_TRIGGER_T6_TRGO; // TIM6触发
sConfig.DAC_OutputBuffer = DAC_OUTPUTBUFFER_DISABLE; // 禁用输出缓冲
sConfig.DAC_UserTrimming = DAC_TRIMMING_FACTORY; // 使用出厂修整值
if (HAL_DAC_ConfigChannel(&hdac1, &sConfig, DAC_CHANNEL_1) != HAL_OK) {
Error_Handler();
}
3.3 DAC 输出控制
3.3.1 设置 DAC 值
// 设置DAC通道值
HAL_StatusTypeDef HAL_DAC_SetValue(
DAC_HandleTypeDef *hdac,
uint32_t Channel,
uint32_t Alignment,
uint32_t Data)
参数:
-
Alignment: 数据对齐方式-
DAC_ALIGN_12B_R: 12位右对齐 -
DAC_ALIGN_12B_L: 12位左对齐 -
DAC_ALIGN_8B_R: 8位右对齐
-
-
Data: 要转换的数字值 (0-4095 或 0-255)
3.3.2 启动/停止 DAC 转换
// 启动DAC转换
HAL_StatusTypeDef HAL_DAC_Start(
DAC_HandleTypeDef *hdac,
uint32_t Channel)
// 停止DAC转换
HAL_StatusTypeDef HAL_DAC_Stop(
DAC_HandleTypeDef *hdac,
uint32_t Channel)
示例 (输出1.65V):
// 设置DAC值 (3.3V参考电压下1.65V对应2048)
HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, 2048);
// 启动DAC转换 (软件触发)
HAL_DAC_Start(&hdac1, DAC_CHANNEL_1);
3.4 DAC 波形生成
3.4.1 三角波生成
HAL_StatusTypeDef HAL_DACEx_TriangleWaveGenerate(
DAC_HandleTypeDef *hdac,
uint32_t Channel,
uint32_t Amplitude)
参数:
-
Amplitude: 三角波幅度-
DAC_TRIANGLEAMPLITUDE_1: 1 -
DAC_TRIANGLEAMPLITUDE_3: 3 -
...
-
DAC_TRIANGLEAMPLITUDE_4095: 4095
-
3.4.2 噪声波生成
HAL_StatusTypeDef HAL_DACEx_NoiseWaveGenerate(
DAC_HandleTypeDef *hdac,
uint32_t Channel,
uint32_t Amplitude)
参数: 同三角波
3.4.3 双通道同步
// 同时启动两个通道
HAL_DAC_Start(&hdac1, DAC_CHANNEL_1 | DAC_CHANNEL_2);
// 同时设置两个通道的值
HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, value1);
HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_2, DAC_ALIGN_12B_R, value2);
3.5 DAC DMA 传输
3.5.1 启动 DMA 传输
HAL_StatusTypeDef HAL_DAC_Start_DMA(
DAC_HandleTypeDef *hdac,
uint32_t Channel,
uint32_t *pData,
uint32_t Length,
uint32_t Alignment)
功能: 通过 DMA 连续输出数据流
示例 (正弦波生成):
#define SINE_WAVE_SAMPLES 128
uint32_t sine_wave[SINE_WAVE_SAMPLES];
// 生成正弦波表
void Generate_Sine_Wave(void) {
for (int i = 0; i < SINE_WAVE_SAMPLES; i++) {
sine_wave[i] = (uint32_t)(2047.5 * (1 + sin(2 * M_PI * i / SINE_WAVE_SAMPLES)));
}
}
// 启动DAC DMA传输
HAL_DAC_Start_DMA(&hdac1, DAC_CHANNEL_1, sine_wave, SINE_WAVE_SAMPLES, DAC_ALIGN_12B_R);
3.5.2 停止 DMA 传输
HAL_StatusTypeDef HAL_DAC_Stop_DMA(
DAC_HandleTypeDef *hdac,
uint32_t Channel)
3.6 DAC 校准
3.6.1 修整值设置
HAL_StatusTypeDef HAL_DACEx_SetUserTrimming(
DAC_HandleTypeDef *hdac,
uint32_t Channel,
uint32_t NewTrimming)
3.6.2 获取修整值
uint32_t HAL_DACEx_GetTrimOffset(
DAC_HandleTypeDef *hdac,
uint32_t Channel,
uint32_t Trimming)
3.6.3 自校准
HAL_StatusTypeDef HAL_DACEx_SelfCalibrate(
DAC_HandleTypeDef *hdac,
DAC_ChannelConfTypeDef *sConfig,
uint32_t Channel)
示例:
// 使用出厂修整值
DAC_ChannelConfTypeDef sConfig = {0};
sConfig.DAC_UserTrimming = DAC_TRIMMING_FACTORY;
HAL_DAC_ConfigChannel(&hdac1, &sConfig, DAC_CHANNEL_1);
HAL_DACEx_SelfCalibrate(&hdac1, &sConfig, DAC_CHANNEL_1);
3.7 DAC 中断处理
3.7.1 中断服务函数
// DAC中断服务函数
void DAC_IRQHandler(void) {
HAL_DAC_IRQHandler(&hdac1);
}
3.7.2 回调函数
// DMA传输完成回调
void HAL_DAC_ConvCpltCallbackCh1(DAC_HandleTypeDef *hdac) {
// 处理DMA传输完成事件
}
// DMA半传输完成回调
void HAL_DAC_ConvHalfCpltCallbackCh1(DAC_HandleTypeDef *hdac) {
// 处理半传输完成事件
}
// 错误回调
void HAL_DAC_ErrorCallbackCh1(DAC_HandleTypeDef *hdac) {
// 处理DAC错误
}
3.8 DAC 状态管理
3.8.1 状态获取函数
// 获取DAC状态
HAL_DAC_StateTypeDef HAL_DAC_GetState(DAC_HandleTypeDef *hdac)
// 获取错误代码
uint32_t HAL_DAC_GetError(DAC_HandleTypeDef *hdac)
3.8.2 状态枚举
HAL_DAC_STATE_RESET // 复位状态
HAL_DAC_STATE_READY // 就绪状态
HAL_DAC_STATE_BUSY // 忙状态
HAL_DAC_STATE_TIMEOUT // 超时状态
HAL_DAC_STATE_ERROR // 错误状态
浙公网安备 33010602011771号