//****************************************************************************** // MSP430F20x2 Demo - ADC10, Sample A7, 1.5V, TA1 Trig, Ultra-Low Pwr // // Description: A7 is sampled 1024/second (32xACLK)with reference to 1.5V All // activity is interrupt driven with proper usage of MSP430 low-power modes, // ADC10 and Vref demonstrated Timer_A with both TA1/TA0 used in upmode to // drive ADC10 conversion (continuous mode can also be used) Inside // of TA0_ISR software will enable ADC10 and internal reference and // allow > 30us delay for Vref to stabilize prior to sample start Sample // start is automatically triggered by TA1 every 32 ACLK cycles ADC10_ISR // will disable ADC10 and Vref and compare ADC10 conversion code Internal // oscillator times sample (16x) and conversion (13x) If A7 > 0.2Vcc, // P1.0 is set, else reset Normal Mode is LPM3 // //* An external watch crystal on XIN XOUT is required for ACLK *// // // + -(0.9766us) -\\ >+ // TA0_ISR TA1 ADC10_ISR TA0_ISR TA1 // -+ + + -\\ + + -> // Enable ADC Trigger ADC Disable ADC // and Vref // Compare +-( >30us ->+ // // // // MSP430F20x2 - // /|\| // || | 32kHz // |RST XOUT|- // // XIN|- | | > -|P1.7/A7 P1.0 | > LED // // L Westlund // Texas Instruments Inc // May 2006 // Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.41A //****************************************************************************** #include "msp430x20x2.h" void main(void) { WDTCTL = WDTPW + WDTHOLD; ADC10CTL1 = INCH_7 + SHS_1; ADC10AE0 = 0x80; // Stop WDT // P1.7, TA1 trigger sample start // P1.7 ADC10 option select P1DIR |= 0x01; // Set P1.0 to output direction TACCTL0 = CCIE; // Enable interrupt TACCR0 = 32-1; // PWM Period TACCTL1 = OUTMOD_3; TACCR1 = 2; TACTL = TASSEL_1 + MC_1; // TACCR1 set/reset // TACCR1 PWM Duty Cycle // ACLK, up mode bis_SR_register(LPM3_bits + GIE); // Enter LPM3, enable interrupts } // ADC10 interrupt service routine #pragma vector=ADC10_VECTOR interrupt void ADC10_ISR(void) { ADC10CTL0 &= ~ENC; ADC10CTL0 = 0; // ADC10 disabled // ADC10, Vref disabled completely if (ADC10MEM < 0x88) P1OUT &= ~0x01; // ADC10MEM = A7 > 0.2V? // Clear P1.0 LED of else P1OUT |= 0x01; // Set P1.0 LED on } // Timer A0 interrupt service routine #pragma vector=TIMERA0_VECTOR interrupt void Timer_A(void) { ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE; ADC10CTL0 |= ENC; } // ADC10 enable set