1、简介
FM33LG0带有最高采样率达到2Msps的12bit SAR-ADC，支持单端输入和差分输入，可以自由选择VREFP或者VDDA作为REF+参考电压，方便灵活；带有一个最高输出率为1Msps，12位的电压输出型数模转换器，需要注意的是DAC使用VREF+作为参考基准，所以在开发板上需要将J40的VP与V用跳帽进行短接！
2、实现功能
使用板载的ADC和DAC扩展接口进行功能验证，ADC使用单通道采集的方式，依次对CH15、CH16、CH17进行采样，计算并打印出电压值；DAC输出通道使用软件写入数据的方式实现正弦波形的输出；最后通过接线的方式，将CH15接VCC、CH16接DAC输出、CH17接GND，来测试在相邻通道的电压值快速变化的情况下，是否会对相邻通道的采样值产生影响。
3、代码实现
/*******************************************************************************
* @file ADC.c
* @author King
* [url=home.php?mod=space&uid=252314]@version[/url] V1.00
* [url=home.php?mod=space&uid=311857]@date[/url] 27-Nov-2021
* [url=home.php?mod=space&uid=159083]@brief[/url] ......
*******************************************************************************/
/* Define to prevent recursive inclusion -------------------------------------*/
#define __ADC_C__
/* Includes ------------------------------------------------------------------*/
#include "ADC.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
/* Exported variables --------------------------------------------------------*/
/* Exported function prototypes ----------------------------------------------*/
/*******************************************************************************
* @brief
* @param
* @retval
* [url=home.php?mod=space&uid=1020061]@attention[/url] *******************************************************************************/
void ADC_Configure(void)
{
FL_GPIO_InitTypeDef GPIO_InitStruct;
FL_ADC_CommonInitTypeDef ADC_CommonInitStruct;
FL_ADC_InitTypeDef ADC_InitStruct ;
FL_GPIO_StructInit(&GPIO_InitStruct);
GPIO_InitStruct.pin = FL_GPIO_PIN_10 | FL_GPIO_PIN_11 | FL_GPIO_PIN_12;
GPIO_InitStruct.mode = FL_GPIO_MODE_ANALOG;
GPIO_InitStruct.outputType = FL_GPIO_OUTPUT_PUSHPULL;
FL_GPIO_Init(GPIOC, &GPIO_InitStruct);
FL_ADC_CommonStructInit(&ADC_CommonInitStruct);
ADC_CommonInitStruct.operationSource = FL_ADC_CLK_SOURCE_ADCCLK;
ADC_CommonInitStruct.clockSource = FL_CMU_ADC_CLK_SOURCE_RCHF;
ADC_CommonInitStruct.clockPrescaler = FL_CMU_ADC_PSC_DIV8;
ADC_CommonInitStruct.APBClockPrescaler = FL_ADC_APBCLK_PSC_DIV1;
ADC_CommonInitStruct.referenceSource = FL_ADC_REF_SOURCE_VDDA;
ADC_CommonInitStruct.bitWidth = FL_ADC_BIT_WIDTH_12B;
FL_ADC_CommonInit(&ADC_CommonInitStruct);
FL_ADC_StructInit(&ADC_InitStruct);
ADC_InitStruct.conversionMode = FL_ADC_CONV_MODE_SINGLE;
ADC_InitStruct.autoMode = FL_ADC_SINGLE_CONV_MODE_AUTO;
ADC_InitStruct.waitMode = FL_ENABLE;
ADC_InitStruct.overrunMode = FL_ENABLE;
ADC_InitStruct.scanDirection = FL_ADC_SEQ_SCAN_DIR_FORWARD;
ADC_InitStruct.externalTrigConv = FL_ADC_TRIGGER_EDGE_NONE;
ADC_InitStruct.triggerSource = FL_ADC_TRGI_LUT0;
ADC_InitStruct.fastChannelTime = FL_ADC_FAST_CH_SAMPLING_TIME_2_ADCCLK;
ADC_InitStruct.lowChannelTime = FL_ADC_SLOW_CH_SAMPLING_TIME_192_ADCCLK;
ADC_InitStruct.oversamplingMode = FL_ENABLE;
ADC_InitStruct.overSampingMultiplier = FL_ADC_OVERSAMPLING_MUL_8X;
ADC_InitStruct.oversamplingShift = FL_ADC_OVERSAMPLING_SHIFT_3B;
FL_ADC_Init(ADC, &ADC_InitStruct);
TASK_Append(TASK_ID_ADC, ADC_Handler, 500);
}
/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
uint32_t ADC_GetSingleChannelSample(uint32_t Channel)
{
uint16_t Data = 0;
FL_CMU_SetADCPrescaler(FL_CMU_ADC_PSC_DIV1);
FL_ADC_EnableSequencerChannel(ADC, Channel);
FL_ADC_ClearFlag_EndOfConversion(ADC);
FL_ADC_Enable(ADC);
FL_ADC_EnableSWConversion(ADC);
while(FL_ADC_IsActiveFlag_EndOfConversion(ADC) == FL_RESET);
FL_ADC_ClearFlag_EndOfConversion(ADC);
Data = FL_ADC_ReadConversionData(ADC);
FL_ADC_Disable(ADC);
FL_ADC_DisableSequencerChannel(ADC, Channel);
return Data;
}
/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void ADC_Handler(void)
{
uint32_t CH15_Data = 0, CH16_Data = 0, CH17_Data = 0;
CH15_Data = ADC_GetSingleChannelSample(FL_ADC_EXTERNAL_CH15);
CH16_Data = ADC_GetSingleChannelSample(FL_ADC_EXTERNAL_CH16);
CH17_Data = ADC_GetSingleChannelSample(FL_ADC_EXTERNAL_CH17);
printf("\r\nCH15 : %0.1fV, CH16 : %0.1fV, CH17 : %0.1fV",
(float)CH15_Data / 4095 * 3.3,
(float)CH16_Data / 4095 * 3.3,
(float)CH17_Data / 4095 * 3.3);
}
/******************* (C) COPYRIGHT 2021 *************************END OF FILE***/
/*******************************************************************************
* @file DAC.c
* @author King
* @version V1.00
* @date 27-Nov-2021
* @brief ......
*******************************************************************************/
/* Define to prevent recursive inclusion -------------------------------------*/
#define __DAC_C__
/* Includes ------------------------------------------------------------------*/
#include "DAC.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
/* Private functions ---------------------------------------------------------*/
/* Exported variables --------------------------------------------------------*/
/* Exported function prototypes ----------------------------------------------*/
/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void DAC_Configure(void)
{
FL_GPIO_InitTypeDef GPIO_InitStruct;
FL_DAC_InitTypeDef DAC_InitStruct;
FL_GPIO_StructInit(&GPIO_InitStruct);
GPIO_InitStruct.pin = FL_GPIO_PIN_5;
GPIO_InitStruct.mode = FL_GPIO_MODE_ANALOG;
GPIO_InitStruct.outputType = FL_GPIO_OUTPUT_PUSHPULL;
FL_GPIO_Init(GPIOC, &GPIO_InitStruct);
FL_DAC_StructInit(&DAC_InitStruct);
DAC_InitStruct.sampleHoldMode = FL_DISABLE;
DAC_InitStruct.sampleTime = 0xFF;
DAC_InitStruct.holdTime = 0x00;
DAC_InitStruct.triggerMode = FL_DISABLE;
DAC_InitStruct.triggerSource = FL_DAC_TRGI_SOFTWARE;
DAC_InitStruct.bufferMode = FL_DISABLE;
DAC_InitStruct.switchMode = FL_ENABLE;
FL_DAC_Init(DAC, &DAC_InitStruct);
FL_DAC_Enable(DAC);
FL_DAC_WriteData(DAC, 2047);
TASK_Append(TASK_ID_DAC, DAC_Handler, 1);
}
/*******************************************************************************
* @brief
* @param
* @retval
* @attention
*******************************************************************************/
void DAC_Handler(void)
{
uint16_t WaveData[1284] =
{
2047,2147,2248,2347,2446,2545,2641,2737,2831,2922,
3012,3100,3185,3267,3346,3422,3495,3564,3630,3692,
3749,3803,3853,3898,3939,3975,4006,4033,4055,4072,
4085,4092,4095,4092,4085,4072,4055,4033,4006,3975,
3939,3898,3853,3803,3749,3692,3630,3564,3495,3422,
3346,3267,3185,3100,3012,2922,2831,2737,2641,2545,
2446,2347,2248,2147,2047,1947,1846,1747,1648,1549,
1453,1357,1263,1172,1082, 994, 909, 827, 748, 672,
599, 530, 464, 402, 345, 291, 241, 196, 155, 119,
88, 61, 39, 22, 9, 2, 0, 2, 9, 22,
39, 61, 88, 119, 155, 196, 241, 291, 345, 402,
464, 530, 599, 672, 748, 827, 909, 994,1082,1172,
1263,1357,1453,1549,1648,1747,1846,1947
};
static uint8_t WaveIndex = 0;
FL_DAC_WriteData(DAC, WaveData[WaveIndex]);
WaveIndex = (WaveIndex + 1) % 128;
}
/******************* (C) COPYRIGHT 2021 *************************END OF FILE***/
4、测试数据
DAC初始化完成后，设定输出VREF+一半的电压值：
软件方式实现正弦波输出：
各个通道采样稳定，没有受到相邻通道的影响：
5、工程源码
引用: Jacktang 发表于 2021-12-5 20:40 软件方式实现输出的正弦波还挺正确 想问一下将J40的VP与V用跳帽进行短接时，这个电压多少V
理论上是3.3V，我这个板子用万用表实测是3.271V
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