请教：ADC12 模块的问题，急！！！

小李啧

请教：ADC12 模块的问题，急！！！ [复制链接]

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; Set Breakpoint here

这些指令是什么意思啊？我C学的不是很好，请各位高手指点一二！跪谢啊！

wstt

不用谢，共同学习

wstt

没有完整的代码，根据以上这些代码我是这样理解的。
首先我猜测该ADC12模块使用了CONSEQx = 11的模式（A sequence of channels is converted repeatedly），也就是对多个通道连续采样。
就以上代码来看应该是4个通道，数组Axresults(x = 0,1,2,3)是用来存储每个通道的采样的数据。

[ 本帖最后由 wstt 于 2011-3-24 10:48 编辑 ]

wstt

Num_of_Results看不大清楚是什么意思,根据后面说的increment results index来看，那就是用来递增Index的，那我可以认为是采样的输出的通道数目即Num_of_Results = 4，当Index = 1的时候，进行index = (index+1)%Num_of_Results后Index=2（（1+1）%4=2），
以此类推Index最大可递增到3，然后又变为0。所以可能该数组大小为4个你所定义的类型（unsigned int？）

fxw451

楼上分析的不错。

小李啧

#include "MSP430x14x.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 they are not used

void main(void)
{
WDTCTL = WDTPW+WDTHOLD; // Stop watchdog timer
P6SEL = 0x0F; // Enable A/D channel inputs
ADC12CTL0 = ADC12ON+MSC+SHT0_8; // Turn on ADC12, extend sampling time
// to avoid overflow of results
ADC12CTL1 = SHP+CONSEQ_3; // Use sampling timer, repeated sequence
ADC12MCTL0 = INCH_0; // ref+=AVcc, channel = A0
ADC12MCTL1 = INCH_1; // ref+=AVcc, channel = A1
ADC12MCTL2 = INCH_2+EOS; // ref+=AVcc, channel = A2, end seq.

ADC12IE = 0x08; // Enable ADC12IFG.3
ADC12CTL0 |= ENC; // Enable conversions
_EINT(); // Enable interrupts
ADC12CTL0 |= ADC12SC; // Start conversion
_BIS_SR(LPM0_bits); // Enter and stay in LPM0
}

#pragma vector=ADC_VECTOR
__interrupt 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
index = (index+1)%Num_of_Results; // Increment results index, modulo; Set Breakpoint here
}


谢谢啊！帮我看看，那几句我看了好多天....

小李啧

真的很谢谢你的回复，听君一句话，胜看十天书啊！感恩！

xiaoxiaox

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