//******************************************************************************
// MSP430F21x2 Demo - ADC10, Sample A0, 1.5V Ref, Set P1.0 if A0 > 0.2V
//
// Description: A single sample is made on A0 with reference to internal
// 1.5V Vref. Software sets ADC10SC to start sample and conversion - ADC10SC
// automatically cleared at EOC. ADC10 internal oscillator times sample (16x)
// and conversion. In Mainloop MSP430 waits in LPM0 to save power until ADC10
// conversion complete, ADC10_ISR will force exit from LPM0 in Mainloop on
// reti. If A0 > 0.2V, P1.0 set, else reset.
//
// MSP430F21x2
// -----------------
// /|\| XIN|-
// | | |
// --|RST XOUT|-
// | |
// >---|P2.0/A0 P1.0|-->LED
//
// A. Dannenberg
// Texas Instruments Inc.
// December 2007
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.41A
//******************************************************************************
#include "msp430x21x2.h"
void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE;
TACCR0 = 30; // Delay to allow Ref to settle
TACCTL0 |= CCIE; // Compare-mode interrupt.
TACTL = TASSEL_2 + MC_1; // TACLK = SMCLK, Up mode.
__bis_SR_register(CPUOFF + GIE); // LPM0, TA0_ISR will force exit
TACCTL0 &= ~CCIE; // Disable timer Interrupt
ADC10AE0 |= 0x01; // P2.0 ADC option select
P1DIR |= 0x01; // Set P1.0 to output direction
for (;;)
{
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0, ADC10_ISR will force exit
if (ADC10MEM < 0x88) // ADC10MEM = A0 > 0.2V?
P1OUT &= ~0x01; // Clear P1.0 LED off
else
P1OUT |= 0x01; // Set P1.0 LED on
}
}
// ADC10 interrupt service routine
#pragma vector=ADC10_VECTOR
__interrupt void ADC10_ISR(void)
{
__bic_SR_register_on_exit(CPUOFF); // Clear CPUOFF bit from 0(SR)
}
#pragma vector=TIMERA0_VECTOR
__interrupt void TA0_ISR(void)
{
TACTL = 0;
LPM0_EXIT; // Exit LPM0 on return
} |
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