MSP430F149单片机初学者常用到的程序代码ADC部分

//****************************************************************************** // 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 IAR Embedded Workbench Version: 3.21A //****************************************************************************** #include <msp430x14x.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 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; // 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(LPM0_bits + GIE); // Enter LPM0, Enable interrupts } #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 A3results[index] = ADC12MEM3; // Move A3 results, IFG is cleared index = (index+1)%Num_of_Results; // Increment results index, modulo; Set Breakpoint here }