CH32V003使用ADC八通道转换注意事项

本文以CH32V003_F4P6(20Pin)为模板

　1、PA1、PA2为外部晶振输入引脚，同时也是ADC的CH1与CH0，所以需要先在system_ch32v00x.c文件中更改为内部48M的宏即可。

注：CH32V003的ADC数据寄存器为10，通道转换值为[0-1024],精度为VCC/1024,VCC与外部参考电压相同[2.8-5.5]

2、ADC初始化与通道配置。

void ADC_Function_Init(void)
{
ADC_InitTypeDef ADC_InitStructure = {0};
GPIO_InitTypeDef GPIO_InitStructure = {0};

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA |RCC_APB2Periph_GPIOC |RCC_APB2Periph_GPIOD, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
RCC_ADCCLKConfig(RCC_PCLK2_Div8);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1|GPIO_Pin_2;//ch0 ch1
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOA, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;//ch2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOC, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3 | GPIO_Pin_5 |GPIO_Pin_6|GPIO_Pin_4;//ch3 ch4 ch5 ch6 ch7
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOD, &GPIO_InitStructure);

ADC_DeInit(ADC1);
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = ENABLE;
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 8;//此处为8个待转换的ADC规则组通道
ADC_Init(ADC1, &ADC_InitStructure);

ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 2, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_2, 3, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_3, 4, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_4, 5, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_5, 6, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_6, 7, ADC_SampleTime_241Cycles);
ADC_RegularChannelConfig(ADC1, ADC_Channel_7, 8, ADC_SampleTime_241Cycles);
ADC_DMACmd(ADC1, ENABLE);
ADC_Cmd(ADC1, ENABLE);

ADC_ResetCalibration(ADC1);
while(ADC_GetResetCalibrationStatus(ADC1));
ADC_StartCalibration(ADC1);
while(ADC_GetCalibrationStatus(ADC1));
}

3、DMA配置.

void DMA_Tx_Init(DMA_Channel_TypeDef *DMA_CHx, u32 ppadr, u32 memadr, u16 bufsize)
{
DMA_InitTypeDef DMA_InitStructure = {0};

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);

DMA_DeInit(DMA_CHx);
DMA_InitStructure.DMA_PeripheralBaseAddr = ppadr;
DMA_InitStructure.DMA_MemoryBaseAddr = memadr;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = bufsize;
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_Normal;//单次扫描转换，可以开启DMA中断，此处改为循环模式
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
DMA_Init(DMA_CHx, &DMA_InitStructure);
}

4、mian函数中需要在开启ADC开始转换之前调用DMA通道初始化与使能，否则ADC_ValueBuf中的数据与通道会不对应（ADC_ValueBuf[0]-ADC_ValueBuf[7]对应ADC通道的0-7的采样值）

int main(void)
{
u16 i;

Delay_Init();
USART_Printf_Init(115200);
printf("SystemClk:%d\r\n", SystemCoreClock);

ADC_Function_Init();

DMA_Tx_Init(DMA1_Channel1, (u32)&ADC1->RDATAR, (u32)ADC_ValueBuf, 8);
DMA_Cmd(DMA1_Channel1, ENABLE);

ADC_SoftwareStartConvCmd(ADC1, ENABLE);
Delay_Ms(50);
ADC_SoftwareStartConvCmd(ADC1, DISABLE);//若DMA工作在循环模式，此处不需要关闭触发。

for(i = 0; i < 8; i++){
printf("%04d\r\n", ADC_ValueBuf[i]);
Delay_Ms(10);
}

while(1);
}