Multiple ADC Channel Reading in using MSP430G2335

Indeed there are examples. Check your chip product page, look for source code examples, there are plenty of ADC examples. One using multiple inputs: msp430g2x33_adc10_10.c

Asokfair,

I don't think a MSP430G2335 exists at all. Typo in the name?
But Ilmars already searched for the most likely derivate for you - the MSP430G2333. Or maybe a MSP430G2353.

Dennis

Thank you Dennis!

I tried to read the 3 ADC values in a array but it doesn't works any idea?
my code/

unsigned int read_adc[3];

ADC10CTL0 &= ~ENC;
while (ADC10CTL1 & BUSY); // Wait if ADC10 core is active
ADC10SA = read_adc; // Data buffer start
P1OUT |= 0x01; // P1.0 = 1
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0, ADC10_ISR will force exit
P1OUT &= ~0x01;


Thanks,
Ashok r

Asokfair,

Please show your complete code including the initialization.

You should not disable the conversions and then wait for the ADC core to have finished conversions on his own. That does not make much sense.

Dennis

The complete code is here,

*****************************************************************************
#include <msp430.h>

unsigned int read_val[3];

int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
ADC10CTL1 = INCH_3 + CONSEQ_1; // A3/A2/A1, single sequence
ADC10CTL0 = ADC10SHT_2 + MSC + ADC10ON + ADC10IE;
ADC10DTC1 = 0x03; // 3 conversions
ADC10AE0 |= 0x0E; // P1.3,2,1 ADC10 option select
P1DIR |= 0x01; // Set P1.0 output

for (;;)
{
ADC10CTL0 &= ~ENC;
while (ADC10CTL1 & BUSY); // Wait if ADC10 core is active
ADC10SA = read_val; // Data buffer start
P1OUT |= 0x01; // P1.0 = 1
ADC10CTL0 |= ENC + ADC10SC; // Sampling and conversion start
__bis_SR_register(CPUOFF + GIE); // LPM0, ADC10_ISR will force exit
P1OUT &= ~0x01; // P1.0 = 0
}
}

// ADC10 interrupt service routine
#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector=ADC10_VECTOR
__interrupt void ADC10_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(ADC10_VECTOR))) ADC10_ISR (void)
#else
#error Compiler not supported!
#endif
{
__bic_SR_register_on_exit(CPUOFF); // Clear CPUOFF bit from 0(SR)
}

Asokfair,

Is that 1:1 the sample program from the code examples? Or did you change something?

It looks like msp430g2x33_adc10_10.c which Ilmars has mentioned. But I did not compare every line. Which processor are you using? Is it the LaunchPad with the MSP430G2553?

Dennis

Hi Dennis,

I didn't make any changes in the code. Only the byte array is introduced.

Yes i am using MSP430G2335 with launchpad

Thanks,

Ashok r

OK, then what does not work in detail?

I am not able to get the ADC outputs in a 3 byte array

Does the example code that puts the values into RAM work on your board?

i checked 0x200 ,0x202 and 0x204 but the value not changing for variation in the input.

I have tested your program and it works fine.

I connected all analog inputs to Vcc.

Dennis

can you ground the signal and check each pins?

Resistor divider:

3.3V - 20k5 - 10k5 - GND

Should give about 1.118V.

Or in ADC result: 1.118V / 3.3V * 1023 = 346

There it is:

Dennis

Btw.: I said clearing ENC and then waiting for the ADC to have finished does not make sense. Forget that. In a sequence it is OK to clear ENC since the running sequence is completed. In single channel single conversion mode it would stop the currently running conversion.

Thanks Dennis,

Don't know what was the problem , now started working

Thanks,

Ashok r

Glad it now works!

Dennis