c - Atmel AVR ADMUX 寄存器未分配值

Question

我有以下枚举和结构:

typedef enum reference{
    AREF = 0, //External on AREF pin
    AVCC = true << REFS0, //Analogue supply voltage
    I11 = true << REFS1, //Internal 1.1V reference
    I256 = true << REFS1 | true <<REFS0 //Internal 2.56 reference
} Reference;

typedef enum channel{
    ADC0 = 0,
    ADC1 = true << MUX0,
    ADC2 = true << MUX1,
    ADC3 = true << MUX0 | true << MUX1,
    ADC4 = true << MUX2,
    ADC5 = true << MUX2 | true << MUX0,
    ADC6 = true << MUX2 | true << MUX1,
    ADC7 = true << MUX2 | true << MUX1 | true << MUX0
    //If higher channels are needed continue using MUXn for n = 0-> 4 in a binary count.
} Channel;

typedef enum leftadjust{
    LADisabled = 0,
    LAEnabled = true << ADLAR
} LeftAdjust;

//Enums for ADCSRA
typedef enum adcenable{
    ADCDisabled = 0,
    ADCEnabled = true << ADEN
} ADCEnable;

typedef enum adcautotriggerenable{
    AutoTriggerDisabled = 0,
    AutoTriggerEnabled = true << ADATE
} ADCAutoTriggerEnable;

typedef enum adcinterruptenable{
    ADCIntteruptDisabled = 0,
    ADCInterruptEnabled = true << ADIE,
} ADCInterruptEnable;

typedef enum adcclockdivider{
    CDHalf = 0,
    CDQuarter = true << ADPS1,
    CDEighth = true << ADPS1 | true << ADPS0,
    CDSixteenth = true << ADPS2,
    CDThirtySecond = true << ADPS2 | true << ADPS0,
    CDSixtyFourth = true << ADPS2 | true << ADPS1,
    CDOneTwoEighth = true << ADPS2 | true << ADPS1| true << ADPS0
} ADCClockDivider;

///structs
typedef struct ADCSettings{
    Reference ref;
    LeftAdjust leftAdjust;
    Channel channel;
    ADCAutoTriggerEnable autoTrigger;
    ADCInterruptEnable interruptEnable;
    ADCClockDivider clockDivider;
    } ADCSettings;

这个构造函数:

ADCSettings* NewADCSettings()
{
    return (ADCSettings*)malloc(sizeof(ADCSettings));
}

然后用这个函数来设置我的 ADC:

void InitialiseADC(ADCSettings* settings)
{
    /*
        13CCs for a conversion. 50ns/cc therefore 0 clock division conversion time is 13 * 50ns =650ns.
        for 50us; 50us/950ns = 77.
        We have 16,32,64 and 128, 64 gives a time of 61us which is in range.
    */
    ADMUX = (settings->ref | settings ->leftAdjust | settings->channel);
    //ADMUX = true << REFS0 | true << MUX1 | true << MUX0; //REFSn sets voltage ref source, MUXn sets channel

    DIDR0 = true << ADC3D; //DIDR is digital input disable (makes a pin analogue)
    ADCSRA = true << ADEN | settings ->autoTrigger | settings ->interruptEnable | settings ->leftAdjust | settings->clockDivider;
    //ADCSRA = true << ADEN | true << ADPS2 | true << ADPS1; //ADPS1 & ADPS2 gives 64 scale

}

正如你所看到的，我正在重构它，尝试使其成为一个很好的库函数，而不是仅仅按照我需要的方式设置它一次。注释掉的行工作得很好。

当我运行这个时，我相信ADMUX应该被分配67，但它取而代之的是64的值，如果我是没有错误的是只是 REFS0 被设置，而 MUX0 和 MUX1 都没有设置。

寄存器是 8 位的，因此它应该能够保存高达 255 的值。

为了完整性，这是我的 main.c:

#include "misc/utilities.h"
#include <avr/io.h>
#include <util/delay.h>
#include <stdbool.h>
#include "USART/USART.h"
#include "ADC/ADC.h"

int main()
{
    ADCSettings* settings = NewADCSettings();
    settings->autoTrigger = false;
    settings->channel=ADC3;
    settings->clockDivider=CDSixtyFourth;
    settings->interruptEnable=false;
    settings->leftAdjust=false;
    settings->ref=AVCC;
    InitialiseADC(settings);
    while (true) 
    {
        int adcReading = GetADCConversion();
        Tx_Line(IntToString(adcReading));
        _delay_ms(100);
    }
}

USART 库和实用程序库之前已经使用过，所以我很确定它们没问题。

有什么想法我哪里出错了吗？

Answer 1

事实证明我的 ADC 设置根本没有问题。

寄存器的问题似乎只是模拟器更新监 window 口中的值的延迟。

我无法获取值的原因是我忘记从库中运行 InitialiseUART() 命令。

这个故事的寓意是，确保初始化所有外围设备。

<小时/>

评论中的其他建议:

1. 不要在小型 uC 上使用动态内存分配。
2. 不要依赖枚举的数值，使用#define