msp430x20x2 adc10 12

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 co

//****************************************************************************** // 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

//

-// /|\|

XIN|-// | | | 32kHz

// |RST

XOUT|-// | |

// > -|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; // Stop WDT

ADC10CTL1 = INCH_7 + SHS_1; // P1.7, TA1 trigger sample start

ADC10AE0 = 0x80; // 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 set/reset

TACCR1 = 2; // TACCR1 PWM Duty Cycle

TACTL = TASSEL_1 + MC_1; // 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; // ADC10 disabled

ADC10CTL0 = 0; // ADC10, Vref disabled completely

if (ADC10MEM < 0x88) // ADC10MEM = A7 > 0.2V?

P1OUT &= ~0x01; // 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

}