一、硬件连接:
1. +3.3V 串3个10k电阻到地 取中间电阻电压(1.10V)送AD 得到码数为:2610
2. +5V 串3个10k电阻到地 取中间电阻电压(1.66V)送AD 得到码数为:2915
3. ADC1_IN1->PA0 接信号+
ADC1_IN2->PA1 接信号-
二、问题:为何电压和码数无法对应呢?
三、代码:(cube生成)
/** System Clock Configura
tion
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInit;
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSICalibrationValue = 16;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL16;
HAL_RCC_OscConfig(&RCC_OscInitStruct);
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2);
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_HRTIM1|RCC_PERIPHCLK_USART1
|RCC_PERIPHCLK_ADC12;
PeriphClkInit.Usart1ClockSelection = RCC_USART1CLKSOURCE_PCLK1;
PeriphClkInit.Adc12ClockSelection = RCC_ADC12PLLCLK_DIV1;
PeriphClkInit.Hrtim1ClockSelection = RCC_HRTIM1CLK_PLLCLK;
HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit);
__SYSCFG_CLK_ENABLE();
}
*******************************************************
/* ADC1 init function */
void MX_ADC1_Init(void)
{
ADC_ChannelConfTypeDef sConfig;
/**Common config
*/
hadc1.Instance = ADC1;
hadc1.Init.ClockPrescaler = ADC_CLOCK_ASYNC;
hadc1.Init.Resolution = ADC_RESOLUTION12b;
hadc1.Init.ScanConvMode = ADC_SCAN_DISABLE;
hadc1.Init.ContinuousConvMode = ENABLE;
hadc1.Init.DiscontinuousConvMode = DISABLE;
hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
hadc1.Init.NbrOfConversion = 1;
hadc1.Init.DMAContinuousRequests = DISABLE;
hadc1.Init.EOCSelection = EOC_SINGLE_CONV;
hadc1.Init.LowPowerAutoWait = DISABLE;
hadc1.Init.Overrun = OVR_DATA_OVERWRITTEN;
HAL_ADC_Init(&hadc1);
/**Configure Regular Channel
*/
sConfig.Channel = ADC_CHANNEL_1;
sConfig.Rank = 1;
sConfig.SingleDiff = ADC_DIFFERENTIAL_ENDED;
sConfig.SamplingTime = ADC_SAMPLETIME_1CYCLE_5;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
sConfig.Offset = 0;
HAL_ADC_ConfigChannel(&hadc1, &sConfig);
}
*******************************************************
HAL_ADC_Start(&hadc1);
while (1)
{
ADC_GetValue=HAL_ADC_GetValue(&hadc1);
printf("%d
", ADC_GetValue);
}
满码:4096
差分信号输入
1.10V送AD 得到码数为:2610
1.66V送AD 得到码数为:2915
请教码数和电压的换算关系?是不是选择了差分输入则AD自动为双极性?
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