【求助】149的AD

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【求助】149的AD [复制链接]

求助一段149的测量（××cc－××ss）/2的一段程序
12位时FFF是否对应着参考电压值？
我用mem0测得值还是比较准的

用mem2 根本没有反应
请高手指点迷津
程序如下
void adc_ini()
{
ADC12CTL0 &=~ENC;
ADC12CTL0=REFON+REF2_5V+SHT0_15+SHT1_15;

ADC12CTL1=CSTARTADD_0+SHP;
ADC12MCTL0=INCH_11+EOS＋SREF_1;
ADC12CTL0|=ADC12ON;
ADC12CTL0|=ENC;
}
main()
{ while(1)
{
int i,result;
adc_ini();
ADC12CTL0|=ADC12SC;
for (i=0;i<1000000;i++);
ADC12CTL0 &=~ENC;
result=ADC12MEM0;

}
}
为什么说result为无效变量 不能获得数值

liuliu987

#include "msp430x44x.h" // Standard Equations

#define Num_of_Results 8

static unsigned int A0results[Num_of_Results]; // These need to be global in
static unsigned int A1results[Num_of_Results]; // this example. Otherwise, the
static unsigned int A2results[Num_of_Results]; // compiler removes them because
static unsigned int A3results[Num_of_Results]; // they are not used

void main(void)
{
WDTCTL = WDTPW+WDTHOLD; // Stop watchdog timer
P6SEL = 0x0F; // Ena××e A/D channel inputs
ADC12CTL0 = ADC12ON+MSC+SHT0_8; // Turn on ADC12, extend sampling time
// to ××oid overflow of results
ADC12CTL1 = SHP+CONSEQ_3; // Use sampling timer, repeated sequence
ADC12MCTL0 = INCH_0; // ref+=××cc, channel = A0
ADC12MCTL1 = INCH_1; // ref+=××cc, channel = A1
ADC12MCTL2 = INCH_2; // ref+=××cc, channel = A2
ADC12MCTL3 = INCH_3+EOS; // ref+=××cc, channel = A3, end seq.
ADC12IE = 0x08; // Ena××e ADC12IFG.3
ADC12CTL0 |= ENC; // Ena××e conversions
_EINT(); // Ena××e interrupts
ADC12CTL0 |= ADC12SC; // Start conversion
_BIS_SR(LPM0_bits); // Enter and stay in LPM0
}

interrupt[ADC_VECTOR] void ADC12ISR (void)
{
static unsigned int index = 0;

A0results[index] = ADC12MEM0; // Move A0 results, IFG is cleared
A1results[index] = ADC12MEM1; // Move A1 results, IFG is cleared
A2results[index] = ADC12MEM2; // Move A2 results, IFG is cleared
A3results[index] = ADC12MEM3; // Move A3 results, IFG is cleared
index = (index+1)%Num_of_Results; // Increment results index, modulo
}
给你个例程吧

bbs_cq

[quote=lsdfae18]

#include "msp430x44x.h" // Standard Equations

#define Num_of_Results 8

static unsigned int A0results[Num_of_Results]; // These need to be global in
static unsigned int A1results[Num_of_Results]; // this example. Otherwise, the
static unsigned int A2results[Num_of_Results]; // compiler removes them because
static unsigned int A3results[Num_of_Results]; // they are not used

void main(void)
{
WDTCTL = WDTPW+WDTHOLD; // Stop watchdog timer
P6SEL = 0x0F; // Ena××e A/D channel inputs
ADC12CTL0 = ADC12ON+MSC+SHT0_8; // Turn on ADC12, extend sampling time
// to ××oid overflow of results
ADC12CTL1 = SHP+CONSEQ_3; // Use sampling timer, repeated sequence
ADC12MCTL0 = INCH_0; // ref+=××cc, channel = A0
ADC12MCTL1 = INCH_1; // ref+=××cc, channel = A1
ADC12MCTL2 = INCH_2; // ref+=××cc, channel = A2
ADC12MCTL3 = INCH_3+EOS; // ref+=××cc, channel = A3, end seq.
ADC12IE = 0x08; // Ena××e ADC12IFG.3
ADC12CTL0 |= ENC; // Ena××e conversions
_EINT(); // Ena××e interrupts
ADC12CTL0 |= ADC12SC; // Start conversion
_BIS_SR(LPM0_bits); // Enter and stay in LPM0
}

interrupt[ADC_VECTOR] void ADC12ISR (void)
{
static unsigned int index = 0;

A0results[index] = ADC12MEM0; // Move A0 results, IFG is cleared
A1results[index] = ADC12MEM1; // Move A1 results, IFG is cleared
A2results[index] = ADC12MEM2; // Move A2 results, IFG is cleared
A3results[index] = ADC12MEM3; // Move A3 results, IFG is cleared
index = (index+1)%Num_of_Results; // Increment results index, modulo
}


版主，你给的这个例程看起来真舒服，不过，有几个地方，我不大理解：
A0results[index] = ADC12MEM0; 这个不仅仅完成了赋值的过程吗，怎么会给相应标志位IFG清零了呢？
ADC12MCTL0 = INCH_0; 这个不仅仅完成通道选择吗，怎么ref+=××cc，是否ADC12MCTLx寄存器默认值就为0x0000h？那么其他的寄存器呢？包括I/O口，其初始值，也就是默认值为什么呢，我找了好久，都没有找到汇总资料，希望版主能够提供，Tks！
还有，我看了很多程序，ISR中都有低功耗唤醒语句，如：LMP4_EXIT语句。这里好像没有看到？

Thanks！ & BestRegards！！谢谢版主。

lightofficer

标志位IFG没有清零啊
不知道是否影响AD转换啊
请高人指点

yuno1

ADC12MEMX被访问过就会清出标志位.

crt689

"A0results[index] = ADC12MEM0; 这个不仅仅完成了赋值的过程吗，怎么会给相应标志位IFG清零了呢？"访问ADC12MEMx后会自动清零的。
“ADC12MCTLx”默认值是POR复位。
所有寄存器的初始状态在USER GUIDE中的每个模块寄存器部分都有。无初始状态的：例如BASIC TIMER的都会单独在NOTE中写明
“LMP4_EXIT语句”是退出低功耗，但AD转换不需要CPU干预，这个程序没有做其他事情所以没有唤醒的语句。

liuwang

那个最后一句怎么理解啊~