【LaunchPad学习】 MSP430G2452电容测量问题

littleshrimp

【LaunchPad学习】 MSP430G2452电容测量问题 [复制链接]

 

想通过P1.1测量电容量，可是代码跑起来后，在不同时刻meas_cnt的值却始终为0。

使用官方的msp430g2xx2_pinosc_01.c代码测量到的meas_cnt也始终为0.p1.0,p1.6的LED不断闪烁。

上面是修改后的代码，在meas_cnt处设置了断点。

2. //******************************************************************************
   //  MSP430G2xx2 Demo - Capacitive Touch, Pin Oscillator Method, 1 button
   //
   //  Description: Basic 1-button input using the built-in pin oscillation feature
   //  on GPIO input structure. PinOsc signal feed into TA0CLK. WDT interval is used
   //  to gate the measurements. Difference in measurements indicate button touch.
   //  LEDs flash if input is touched.
   // 
   //  ACLK = VLO = 12kHz, MCLK = SMCLK = 1MHz DCO
   //
   //               MSP430G2xx2
   //             -----------------
   //         /|\|              XIN|-
   //          | |                 |
   //          --|RST          XOUT|-
   //            |                 |
   //            |             P1.1|<--Capacitive Touch Input 1
   //            |                 |
   //
   //  Brandon Elliott/D. Dang
   //  Texas Instruments Inc.
   //  November 2010
   //  Built with IAR Embedded Workbench Version: 5.10
   //******************************************************************************

3. 
   #include  "msp430g2452.h"
   unsigned int meas_cnt;
   void measure_count(void)
   {
                 
     TA0CTL = TASSEL_3+MC_2;                   // TACLK, cont mode
     TA0CCTL1 = CM_3+CCIS_2+CAP;               // Pos&Neg,GND,Cap
   }
   void main(void)
   {
     WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog timer
     BCSCTL1 = CALBC1_1MHZ;                    // Set DCO to 1MHz
     DCOCTL =  CALDCO_1MHZ;
     BCSCTL3 |= LFXT1S_2;                    // LFXT1 = VLO
     P2SEL = 0x00;                             // No XTAL
     measure_count();   
     P1DIR &= ~ BIT1;                        // P1.1 is the input used here
     P1SEL &= ~ BIT1;
     P1SEL2 |= BIT1;
     TA0CTL |= TACLR;                        // Clear Timer_A TAR
     while(1)
     {
         meas_cnt = TACCR0;                      // Save result
     }
   }                                           // End Main

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[ 本帖最后由 littleshrimp 于 2012-6-16 13:43 编辑 ]

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