STM32F103CBT6的ADC输出值非线性跳跃问题，请大侠们帮忙。

mikeliran · 发表于 2014-10-18 22:37:04

搞了一天的ADC DMA单通道模式数据采集，最后才发现一个致命的问题，两块板子都是一模一样的问题，简单的电阻分压送给ADC采集，，更换元件参数问题依旧，至此基本排除硬件电路的问题。
测试方法输入一个线性电压经过电阻分压送给ADC，0-4V步进0.1V，得到一个对应的ADC输出值。
可以观察到，7x 17x 27x 等输出值都是一下子跳到100 200 300的。

[mw_shl_code=c,true]#include "stm32f10x.h" #define ADC1_DR_Address ((uint32_t)0x4001244C) ADC_InitTypeDef ADC_InitStructure; DMA_InitTypeDef DMA_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; __IO u16 AD_Value[30] = {0}; //AD采样值 __IO u16 After_filter[1] = {0}; //AD滤波后 void gpio_cfg(void) { GPIO_InitTypeDef GPIO_InitStructure; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5; //GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN; GPIO_Init(GPIOA, &GPIO_InitStructure); } void rcc_cfg(void) { RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOA, ENABLE); } void delay(unsigned int t) { while( t>0 ) t--; } int GetVolt(u16 advalue) { return (advalue * 50 / 4096); } int x,y; int main(void) { rcc_cfg(); gpio_cfg(); /* DMA1 channel1 configuration ----------------------------------------------*/ DMA_DeInit(DMA1_Channel1); DMA_InitStructure.DMA_PeripheralBaseAddr = ADC1_DR_Address; DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&AD_Value; DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC; DMA_InitStructure.DMA_BufferSize = 30; 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_M2M = DMA_M2M_Disable; DMA_Init(DMA1_Channel1, &DMA_InitStructure); /* Enable DMA1 channel1 */ DMA_Cmd(DMA1_Channel1, ENABLE); DMA_ITConfig(DMA1_Channel1, DMA_IT_TC, ENABLE); //使能DMA传输完成中断 /* ADC1 configuration ------------------------------------------------------*/ ADC_InitStructure.ADC_Mode = ADC_Mode_Independent; ADC_InitStructure.ADC_ScanConvMode = DISABLE; ADC_InitStructure.ADC_ContinuousConvMode = ENABLE; ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None; ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right; ADC_InitStructure.ADC_NbrOfChannel = 1; ADC_Init(ADC1, &ADC_InitStructure); RCC_ADCCLKConfig(RCC_PCLK2_Div8); /* ADC1 regular channel14 configuration */ ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 1, ADC_SampleTime_239Cycles5); /* Enable ADC1 */ ADC_Cmd(ADC1, ENABLE); /* Enable ADC1 DMA */ ADC_DMACmd(ADC1, ENABLE); /* Enable ADC1 reset calibration register */ ADC_ResetCalibration(ADC1); /* Check the end of ADC1 reset calibration register */ while(ADC_GetResetCalibrationStatus(ADC1)); /* Start ADC1 calibration */ ADC_StartCalibration(ADC1); /* Check the end of ADC1 calibration */ while(ADC_GetCalibrationStatus(ADC1)); /* Start ADC1 Software Conversion */ ADC_SoftwareStartConvCmd(ADC1, ENABLE); NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel1_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; NVIC_Init(&NVIC_InitStructure);// Enable the DMA Interrupt while (1) { x = GetVolt(After_filter[0]); y = AD_Value[0]; } } [/mw_shl_code]

现在怀疑两个方向可能出现问题，程序和芯片本身，程序是按照固件库例程修改的，多次查找未找到可能引起这种现象的代码，难道单片机本身有缺陷？