多个IO口采ADC的问题

2019-03-24 08:58发布

请教各位：使用MSP430FR5969

我使用P3.0 （A12）、 P3.2 (A14)、P3.3 (A15 ) 三个IO口，分别采三个ADC，但是都是以第一个采到的ADC的值为准，不会变化

P3.0采2.0V的电压，P3.2采0.5V的电压 P3.3采1.0V的电压，最后得到的结果总是以P3.0的值为准

但是单次分别采各自的电压是正确的，就是3个IO口一起采的时候，会出现这种情况。

请问是通道没有转换所以一直以第一个通道来采电压吗？还是有其他可能？

请教大家，谢谢！

下面是ADC的初始化和采ADC函数代码

void init_adc()
{
//Initialize the ADC12B Module
/*
* Base address of ADC12B Module
* Use internal ADC12B bit as sample/hold signal to start conversion
* USE MODOSC 5MHZ Digital Oscillator as clock source
* Use default clock divider/pre-divider of 1
* Not use internal channel
*/
ADC12_B_initParam initParam = {0};
initParam.sampleHoldSignalSourceSelect = ADC12_B_SAMPLEHOLDSOURCE_SC;
initParam.clockSourceSelect = ADC12_B_CLOCKSOURCE_ADC12OSC;
initParam.clockSourceDivider = ADC12_B_CLOCKDIVIDER_1;
initParam.clockSourcePredivider = ADC12_B_CLOCKPREDIVIDER__1;
initParam.internalChannelMap = ADC12_B_NOINTCH;
ADC12_B_init(ADC12_B_BASE, &initParam);
//Enable the ADC12B module
ADC12_B_enable(ADC12_B_BASE);
/*
* Base address of ADC12B Module
* For memory buffers 0-7 sample/hold for 64 clock cycles
* For memory buffers 8-15 sample/hold for 4 clock cycles (default)
* Disable Multiple Sampling
*/
ADC12_B_setupSamplingTimer(ADC12_B_BASE, ADC12_B_CYCLEHOLD_16_CYCLES,
ADC12_B_CYCLEHOLD_4_CYCLES, ADC12_B_MULTIPLESAMPLESDISABLE);
//Configure Memory Buffer
/*
* Base address of the ADC12B Module
* Configure memory buffer 0
* Map input A3 to memory buffer 0
* Vref+ = AVcc
* Vref- = AVss
* Memory buffer 0 is not the end of a sequence
*/
ADC12_B_configureMemoryParam configureMemoryParam = {0};
configureMemoryParam.memoryBufferControlIndex = ADC12_B_MEMORY_0;
// configureMemoryParam.inputSourceSelect = ADC12_B_INPUT_A3;
configureMemoryParam.refVoltageSourceSelect =
ADC12_B_VREFPOS_AVCC_VREFNEG_VSS;
configureMemoryParam.endOfSequence = ADC12_B_NOTENDOFSEQUENCE;
configureMemoryParam.windowComparatorSelect =
ADC12_B_WINDOW_COMPARATOR_DISABLE;
configureMemoryParam.differentialModeSelect =
ADC12_B_DIFFERENTIAL_MODE_DISABLE;
ADC12_B_configureMemory(ADC12_B_BASE, &configureMemoryParam);
ADC12_B_clearInterrupt(ADC12_B_BASE, 0, ADC12_B_IFG0);
//Enable memory buffer 0 interrupt
ADC12_B_enableInterrupt(ADC12_B_BASE, ADC12_B_IE0, 0, 0);
}

复制代码

uint16_t ADC12_B_Sampling(uint16_t GpioPort, uint16_t GpioPin, uint16_t InputSource)
{
int16_t i16Adcdata[16];
int16_t i16swap = 0;
int16_t i16_temp = 0, i16_temp1 = 0;
GPIO_setAsPeripheralModuleFunctionOutputPin(GpioPort, GpioPin,
GPIO_TERNARY_MODULE_FUNCTION);
HWREG16(ADC12_B_BASE + OFS_ADC12MCTL0 + ADC12_B_MEMORY_0) = InputSource; //Set Input Source
// __bic_SR_register(GIE);
_disable_interrupts();
for (i = 0; i < 16; i++)
{
// 开始采样和转化，在memory buffer 0 ，单通道单次转化
ADC12_B_startConversion(ADC12_B_BASE, ADC12_B_MEMORY_0,
ADC12_B_SINGLECHANNEL);
while (!(HWREG8(ADC12_B_BASE + OFS_ADC12IFGR0) & ADC12IFG0));
ADC_Get_Value = ADC12_B_getResults(ADC12_B_BASE, ADC12_B_MEMORY_0);
HWREG16(ADC12_B_BASE + (OFS_ADC12MEM0 + ADC12_B_MEMORY_0)) = 0;
i16Adcdata[i] = ADC_Get_Value;
__no_operation();
__delay_cycles(5000);
}
// __bis_SR_register(GIE);
_enable_interrupts();
for (i16_temp = 0; i16_temp < 16; i16_temp++)
{
for (i16_temp1 = i16_temp + 1; i16_temp1 < 16; i16_temp1++)
{
if (i16Adcdata[i16_temp] < i16Adcdata[i16_temp1])
{
i16swap = i16Adcdata[i16_temp];
i16Adcdata[i16_temp] = i16Adcdata[i16_temp1];
i16Adcdata[i16_temp1] = i16swap;
}
}
}
for (i16_temp = 5; i16_temp < 12; i16_temp++)
i16Adcdata[4] += i16Adcdata[i16_temp];
i16Adcdata[4] += 8;
i16Adcdata[4] = i16Adcdata[4] >> 3;
ADV_Get_Aver_Value = i16Adcdata[4];
// DEBUG_PRINT(MSG_ALWAYS, "ADV_Get_Aver_Value=====%d ", ADV_Get_Aver_Value);
return ADV_Get_Aver_Value;
}