多个IO口采ADC的问题

只看该作者 · 2016-9-13 16:38

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

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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);

}

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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\r\n", ADV_Get_Aver_Value);



        return ADV_Get_Aver_Value;



}