Hi, ive been trying to trigger an adc12 repeat sequence of channels conversion from timer A1 (because these are the pin outputs i can verify on the launchpad board). The timer runs of an 32 kHz external crystal oscillator and i desire the ADC to sample at 8 kHz. I've looked at several forum posts but none have answered my questions and the data sheet/ user guide is vague on the relationships between the timer and ADC12 trigger.
I set P3.6 to toggle to view timings on an oscilloscope. The PWM triggers correctly however the ADC triggers at around 600 kHz with the MCLK (still active. I have tried the setup from triggering a timer interrupt and starting the ADC via a software however I cannot get this to work.
Please find my code attached and any help would be very much appreciated.
#include <msp430.h>
int main(void)
{
WDTCTL = WDTPW | WDTHOLD; // Stop WDT
// GPIO Setup // Configure GPIO for timer, set all registers to output to reduce current leaks
P1OUT &= ~BIT0; // Clear LED to start
P1DIR |= 0xFF; // Set P1.0/LED to output
P4DIR |= 0xFF;
P3DIR |= 0xFF;
P2DIR |= 0xFF;
PJDIR |= 0xFF;
P1OUT &= ~BIT0; // Clear LED to start
P1DIR |= BIT0; // Set P1.0/LED to output
P1SEL1 |= BIT1; // Configure P1.1 for ADC
P1SEL0 |= BIT1;
P3OUT |= BIT6;
P1SEL0 |= BIT2; // P1.2 options select
//configure gpio for adc
P1SEL1 |= BIT3 | BIT4 | BIT5; // Configure ADC inputs A1, A2 and A3
P1SEL0 |= BIT3 | BIT4 | BIT5;
//enable XTLFO gpio
PJSEL0 |= BIT4 | BIT5;
// Disable the GPIO power-on default high-impedance mode to activate
// previously configured port settings
PM5CTL0 &= ~LOCKLPM5;
FRCTL0 = FRCTLPW | NWAITS0;
// Setup XT1 crystal.Set the Master and SM (16 MHz) and ACLK (XT1)
CSCTL0_H = CSKEY >> 8; // Unlock CS registers
CSCTL1 = DCORSEL | DCOFSEL_4; // Set DCO to 16MHz
CSCTL2 = SELA__LFXTCLK | SELS__DCOCLK | SELM__DCOCLK; // set ACLK = XT1; MCLK = SMCLK = DCO
CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1; // Set all dividers
CSCTL4 &= ~LFXTOFF;
//Wait for the oscilator to settle
do
{
CSCTL5 &= ~LFXTOFFG; // Clear XT1 fault flag
SFRIFG1 &= ~OFIFG;
}while (SFRIFG1&OFIFG); // Test oscillator fault flag
CSCTL0_H = 0; // Lock CS registers
ADC12CTL0 = ADC12MSC | ADC12ON; // Sampling time, ADC12 on
ADC12CTL1 = ADC12CONSEQ1 | ADC12CONSEQ0 | ADC12SHP | ADC12SHS_4; // repeat sequence of channels, triggers from TA1
ADC12CTL2 |= ADC12RES_2; // 12-bit conversion results
ADC12MCTL0 |= ADC12INCH_3; // Channel2 ADC input select; Vref=AVCC
ADC12MCTL1 |= ADC12INCH_4; // Channel2 ADC input select; Vref=AVCC
ADC12MCTL2 |= ADC12INCH_5 | ADC12EOS; // Channel2 ADC input select; Vref=AVCC
ADC12IER0 |= ADC12IE2;
ADC12CTL0 |= ADC12ENC;
//configure timer A1 for puslse width toggle option
TA1CCTL1 = OUTMOD_4; // CCR1 toggle and interrupt enabled
TA1CCR0 = 4-1;
TA1CCR1 = 0;
TA1CTL = TASSEL__ACLK | MC__UP | TACLR; // ACLK, up countmode, clear TAR
__bis_SR_register(LPM3_bits | GIE); // LPM0, ADC12_ISR will force exit
}
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = ADC12_VECTOR
__interrupt void ADC12_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC12_VECTOR))) ADC12_ISR (void)
#else
#error Compiler not supported!
#endif
{
switch(__even_in_range(ADC12IV, ADC12IV_ADC12RDYIFG))
{
case ADC12IV_ADC12IFG2:
P3OUT ^= BIT6;
break; // Vector 16: ADC12MEM2
default: break;
}
}
