为什么ADC12设置为多次转换模式时只能进行一次转换

Hi xiaolong,

   你需要配置是基于sequence的采样吗？是单次的还是多次循环的采样？

在我们的CCS里面有相关的例程，可以供你参考。

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//******************************************************************************
// MSP-FET430P140 Demo - ADC12, Repeated Sequence of Conversions
//
// Description: This example shows how to perform a repeated sequence of
// conversions using "repeat sequence-of-channels" mode. AVcc is used for the
// reference and repeated sequence of conversions is performed on Channels A0,
// A1, A2, and A3. Each conversion result is stored in ADC12MEM0, ADC12MEM1,
// ADC12MEM2, and ADC12MEM3 respectively. After each sequence, the 4 conversion
// results are moved to A0results[], A1results[], A2results[], and A3results[].
// Test by applying voltages to channels A0 - A3. Open a watch window in
// debugger and view the results. Set a breakpoint in the last line to see the
// array values change sequentially.
//
// Note that a sequence has no restrictions on which channels are converted.
// For example, a valid sequence could be A0, A3, A2, A4, A2, A1, A0, and A7.
// See the MSP430x1xx User's Guide for instructions on using the ADC12.
//
//
// MSP430F149
// -----------------
// | |
// Vin0 -->|P6.0/A0 |
// Vin1 -->|P6.1/A1 |
// Vin2 -->|P6.2/A2 |
// Vin3 -->|P6.3/A3 |
// | |
//
//
// M. Mitchell
// Texas Instruments Inc.
// Feb 2005
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.21A
//******************************************************************************

#include <msp430.h>

#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

int 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; // ref+=AVcc, channel = A2
ADC12MCTL3 = INCH_3+EOS; // ref+=AVcc, channel = A3, end seq.
ADC12IE = 0x08; // Enable ADC12IFG.3
ADC12CTL0 |= ENC; // Enable conversions
ADC12CTL0 |= ADC12SC; // Start conversion
__bis_SR_register(LPM0_bits + GIE); // Enter LPM0, Enable interrupts
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR (void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC12_VECTOR))) ADC12ISR (void)
#else
#error Compiler not supported!
#endif
{
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; Set Breakpoint here
}

谢谢

ken