f2272用内部2.5V基准测量单片机供电电压问题

发表于 2015-4-27 18:22

我在这个循环中来测量单片机的供电电压，发现第一次运行时的q的值是340多，第二次及就是200多，发现严重不准，基准电压2.5v，内部通道，采样时64个时钟周期，我用官方的例程也是同样的问题。
测试程序如下：
#include <msp430.h>
int main(void)
{
  unsigned int q;
  WDTCTL = WDTPW + WDTHOLD;                // Stop WDT

  for (;;)
  {
ADC10CTL0 &= ~ENC;                         //ADC10 disabled
ADC10CTL0 &= ~ADC10ON;                //OFF the ADC10
ADC10CTL0 |= SREF_1 + ADC10SHT_0 + REFON + ADC10ON+REF2_5V;
ADC10CTL1 |= INCH_12 + CONSEQ_0 ;
//ADC10CTL0 &= ~ENC;
while(ADC10CTL1 & ADC10BUSY);
ADC10CTL0 |= ENC;
ADC10CTL0 |= ADC10SC; //start convert

while (ADC10CTL1 & ADC10BUSY);//(!(ADC10IFG & ADC10IFG0))

q = ADC10MEM;
ADC10CTL0 &= ~ENC;                         //ADC10 disabled
ADC10CTL0 &= ~ADC10ON;                //OFF the ADC10
  }
}
哪个大神帮我看看什么问题。不胜感激。

发表于 2015-4-27 18:23

顶起！不要沉了！

发表于 2015-4-27 21:34

kanta 发表于 2015-4-27 18:23
顶起！不要沉了！

采集一次间隔一段时间试试

发表于 2015-4-28 00:30

~ENC
~ADC10ON
这两个放到循环体外试试看，循环体内只要ADC10SC

另外，ADC10SHT_0是64个时钟周期？

发表于 2015-4-28 00:38

再有核对一下 <msp430.h> 中被引用的各寄存器和宏定义的值是否正确，尽量使用具体型号的头文件，比如 <msp430x24x.h> 。

发表于 2015-4-28 10:12

感谢各位的回复，我核对了寄存器，寄存器名称正确，hanzhenfei 的回复我试过，在 q = ADC10MEM;设置断点，只有第一次的运行时的值比较接近电源电压。
各位大神有时间再帮我看看是什么问题？
以下是2272的ADC寄存器。
/* ADC10CTL0 */
#define ADC10SC          (0x001)    /* ADC10 Start Conversion */
#define ENC                (0x002)    /* ADC10 Enable Conversion */
#define ADC10IFG          (0x004)    /* ADC10 Interrupt Flag */
#define ADC10IE          (0x008)    /* ADC10 Interrupt Enalbe */
#define ADC10ON          (0x010)    /* ADC10 On/Enable */
#define REFON             (0x020)    /* ADC10 Reference on */
#define REF2_5V          (0x040)    /* ADC10 Ref 0:1.5V / 1:2.5V */
#define MSC                (0x080)    /* ADC10 Multiple SampleConversion */
#define REFBURST          (0x100)    /* ADC10 Reference Burst Mode */
#define REFOUT             (0x200)    /* ADC10 Enalbe output of Ref. */
#define ADC10SR          (0x400)    /* ADC10 Sampling Rate 0:200ksps / 1:50ksps */
#define ADC10SHT0          (0x800)    /* ADC10 Sample Hold Select Bit: 0 */
#define ADC10SHT1          (0x1000u) /* ADC10 Sample Hold Select Bit: 1 */
#define SREF0             (0x2000u) /* ADC10 Reference Select Bit: 0 */
#define SREF1             (0x4000u) /* ADC10 Reference Select Bit: 1 */
#define SREF2             (0x8000u) /* ADC10 Reference Select Bit: 2 */
#define ADC10SHT_0       (0*0x800u) /* 4 x ADC10CLKs */
#define ADC10SHT_1       (1*0x800u) /* 8 x ADC10CLKs */
#define ADC10SHT_2       (2*0x800u) /* 16 x ADC10CLKs */
#define ADC10SHT_3       (3*0x800u) /* 64 x ADC10CLKs */

#define SREF_0             (0*0x2000u)  /* VR+ = AVCC and VR- = AVSS */
#define SREF_1             (1*0x2000u)  /* VR+ = VREF+ and VR- = AVSS */
#define SREF_2             (2*0x2000u)  /* VR+ = VEREF+ and VR- = AVSS */
#define SREF_3             (3*0x2000u)  /* VR+ = VEREF+ and VR- = AVSS */
#define SREF_4             (4*0x2000u)  /* VR+ = AVCC and VR- = VREF-/VEREF- */
#define SREF_5             (5*0x2000u)  /* VR+ = VREF+ and VR- = VREF-/VEREF- */
#define SREF_6             (6*0x2000u)  /* VR+ = VEREF+ and VR- = VREF-/VEREF- */
#define SREF_7             (7*0x2000u)  /* VR+ = VEREF+ and VR- = VREF-/VEREF- */

/* ADC10CTL1 */
#define ADC10BUSY          (0x0001u) /* ADC10 BUSY */
#define CONSEQ0          (0x0002u) /* ADC10 Conversion Sequence Select 0 */
#define CONSEQ1          (0x0004u) /* ADC10 Conversion Sequence Select 1 */
#define ADC10SSEL0       (0x0008u) /* ADC10 Clock Source Select Bit: 0 */
#define ADC10SSEL1       (0x0010u) /* ADC10 Clock Source Select Bit: 1 */
#define ADC10DIV0          (0x0020u) /* ADC10 Clock Divider Select Bit: 0 */
#define ADC10DIV1          (0x0040u) /* ADC10 Clock Divider Select Bit: 1 */
#define ADC10DIV2          (0x0080u) /* ADC10 Clock Divider Select Bit: 2 */
#define ISSH             (0x0100u) /* ADC10 Invert Sample Hold Signal */
#define ADC10DF          (0x0200u) /* ADC10 Data Format 0:binary 1:2's complement */
#define SHS0             (0x0400u) /* ADC10 Sample/Hold Source Bit: 0 */
#define SHS1             (0x0800u) /* ADC10 Sample/Hold Source Bit: 1 */
#define INCH0             (0x1000u) /* ADC10 Input Channel Select Bit: 0 */
#define INCH1             (0x2000u) /* ADC10 Input Channel Select Bit: 1 */
#define INCH2             (0x4000u) /* ADC10 Input Channel Select Bit: 2 */
#define INCH3             (0x8000u) /* ADC10 Input Channel Select Bit: 3 */

#define CONSEQ_0          (0*2u)    /* Single channel single conversion */
#define CONSEQ_1          (1*2u)    /* Sequence of channels */
#define CONSEQ_2          (2*2u)    /* Repeat single channel */
#define CONSEQ_3          (3*2u)    /* Repeat sequence of channels */

#define ADC10SSEL_0       (0*8u)    /* ADC10OSC */
#define ADC10SSEL_1       (1*8u)    /* ACLK */
#define ADC10SSEL_2       (2*8u)    /* MCLK */
#define ADC10SSEL_3       (3*8u)    /* SMCLK */

#define ADC10DIV_0       (0*0x20u) /* ADC10 Clock Divider Select 0 */
#define ADC10DIV_1       (1*0x20u) /* ADC10 Clock Divider Select 1 */
#define ADC10DIV_2       (2*0x20u) /* ADC10 Clock Divider Select 2 */
#define ADC10DIV_3       (3*0x20u) /* ADC10 Clock Divider Select 3 */
#define ADC10DIV_4       (4*0x20u) /* ADC10 Clock Divider Select 4 */
#define ADC10DIV_5       (5*0x20u) /* ADC10 Clock Divider Select 5 */
#define ADC10DIV_6       (6*0x20u) /* ADC10 Clock Divider Select 6 */
#define ADC10DIV_7       (7*0x20u) /* ADC10 Clock Divider Select 7 */

#define SHS_0             (0*0x400u) /* ADC10SC */
#define SHS_1             (1*0x400u) /* TA3 OUT1 */
#define SHS_2             (2*0x400u) /* TA3 OUT0 */
#define SHS_3             (3*0x400u) /* TA3 OUT2 */

#define INCH_0             (0*0x1000u)  /* Selects Channel 0 */
#define INCH_1             (1*0x1000u)  /* Selects Channel 1 */
#define INCH_2             (2*0x1000u)  /* Selects Channel 2 */
#define INCH_3             (3*0x1000u)  /* Selects Channel 3 */
#define INCH_4             (4*0x1000u)  /* Selects Channel 4 */
#define INCH_5             (5*0x1000u)  /* Selects Channel 5 */
#define INCH_6             (6*0x1000u)  /* Selects Channel 6 */
#define INCH_7             (7*0x1000u)  /* Selects Channel 7 */
#define INCH_8             (8*0x1000u)  /* Selects Channel 8 */
#define INCH_9             (9*0x1000u)  /* Selects Channel 9 */
#define INCH_10          (10*0x1000u) /* Selects Channel 10 */
#define INCH_11          (11*0x1000u) /* Selects Channel 11 */
#define INCH_12          (12*0x1000u) /* Selects Channel 12 */
#define INCH_13          (13*0x1000u) /* Selects Channel 13 */
#define INCH_14          (14*0x1000u) /* Selects Channel 14 */
#define INCH_15          (15*0x1000u) /* Selects Channel 15 */

/* ADC10DTC0 */
#define ADC10FETCH       (0x001)    /* This bit should normally be reset */
#define ADC10B1          (0x002)    /* ADC10 block one */
#define ADC10CT          (0x004)    /* ADC10 continuous transfer */
#define ADC10TB          (0x008)    /* ADC10 two-block mode */
#define ADC10DISABLE       (0x000)    /* ADC10DTC1 */

发表于 2015-4-28 10:15

yirongfu 的方法我也试过，结果一样，郁闷啊

发表于 2015-4-28 12:38

ADC10CTL0 |= SREF_1 + ADC10SHT_0 + REFON + ADC10ON+REF2_5V;
ADC10CTL1 |= INCH_12 + CONSEQ_0 ;这两句放在for循环上面，初始化一次以后不再初始化了。还有ad多关几次看看。

发表于 2015-4-28 12:41

ADC10CTL0 |= ENC;
ADC10CTL0 |= ADC10SC; //start c这两句写成一句看看

发表于 2015-4-28 15:08

hanzhenfei ,我按照你所说的更改，代码如下图，结果跟上次一样不行，还有高招没？
int main(void)
{
  unsigned int q,count;
  WDTCTL = WDTPW + WDTHOLD;                // Stop WDT

  ADC10CTL0 |= SREF_1 + ADC10SHT_3 + REFON + ADC10ON + REF2_5V;
  ADC10CTL1 |= INCH_12 + CONSEQ_0;// + ADC10SSEL_2 +ADC10DIV2 ;
  for (;;)
  {
ADC10CTL0 |= ENC + ADC10SC;

while (ADC10CTL1 & ADC10BUSY);//(!(ADC10IFG & ADC10IFG0))
q = ADC10MEM;
for (count = 0; count< 255; count++);
ADC10CTL0 &= ~ADC10SC; //start convert
ADC10CTL0 &= ~ENC;                         //ADC10 disabled
  }
}

登录 · 发表于 2015-4-28 16:24

改通道 INCH_11试试看？

发表于 2015-4-29 08:24

采集一段时间然后求平均值呢？

发表于 2015-4-30 08:49

采集一段时间做平均试一下呢？

f2272用内部2.5V基准测量单片机供电电压问题

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