Back
//******************************************************************************
// MSP430x24x Demo - ADC12, Sequence of Conversions (non-repeated)
//
// Description: This example shows how to perform A/D conversions on a sequence
// of channels. A single sequence of conversions is performed - one conversion
// each on channels A0, A1, A2, and A3. Each conversion uses AVcc and AVss for
// the references. The conversion results are stored in ADC12MEM0, ADC12MEM1,
// ADC12MEM2, and ADC12MEM3 respectively and are moved to 'results[]' upon
// completion of the sequence. Test by applying voltages to pins A0, A1, A2,
// and A3, then setting and running to a break point at the "_BIC..."
// instruction in the ISR. To view the conversion results, open a watch window
// in debugger and view 'results' or view ADC12MEM0, ADC12MEM1, ADC12MEM2, and
// ADC12MEM3 in an ADC12 SFR window.
// This can run even in LPM4 mode as ADC has its own clock
// 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.
//
// MSP430F249
// -----------------
// | |
// Vin0 -->|P6.0/A0 |
// Vin1 -->|P6.1/A1 |
// Vin2 -->|P6.2/A2 |
// Vin3 -->|P6.3/A3 |
// | |
//
// B. Nisarga
// Texas Instruments Inc.
// September 2007
// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.42A
//******************************************************************************
#include <msp430x24x.h>
volatile unsigned int results[4]; // Needs to be global in this example
// Otherwise, the compiler removes it
// because it is not used for anything.
void main(void)
{
WDTCTL = WDTPW+WDTHOLD; // Stop watchdog timer
P6SEL = 0x0F; // Enable A/D channel inputs
ADC12CTL0 = ADC12ON+MSC+SHT0_2; // Turn on ADC12, set sampling time
ADC12CTL1 = SHP+CONSEQ_1; // Use sampling timer, single 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
while(1)
{
ADC12CTL0 |= ADC12SC; // Start convn - software trigger
_BIS_SR(LPM0_bits + GIE); // Enter LPM0, Enable interrupts
}
}
#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR (void)
{
results[0] = ADC12MEM0; // Move results, IFG is cleared
results[1] = ADC12MEM1; // Move results, IFG is cleared
results[2] = ADC12MEM2; // Move results, IFG is cleared
results[3] = ADC12MEM3; // Move results, IFG is cleared
_BIC_SR_IRQ(LPM0_bits); // Clear LPM0, SET BREAKPOINT HERE
}
|