adc polling method with single channel in LPC1788

Hello everyone,

I am working with ADC Polling method in LPC1788 and I am using 16*2 LCD for displaying the converted value.

I did all settings as mentioned in user manual and readed the channel 0 as mentioned below.But my LCD is flooding with unmatched values.

my adc settings and reading procedure is as follows,

void adc_init()
{ LPC_SC->PCONP |= (1<<12); //Power up for ADC

LPC_IOCON->P0_23 &= ~(0x07<<0); //clearing the function of ADC0 pin

LPC_IOCON->P0_23 |= (0x01 & (0x07<<0)); //Selecting func for P0_23 as adc

LPC_GPIO0->DIR |= (0<<23); //Making ADC0[0]-P0.23 as input

LPC_ADC->CR = (1<<0) |(0<<8) | (1<<21); //ADC0[0],so SEL=0x01,clkdiv_ADC=0,PDN=1
}

int adc_read()
{ unsigned int adc_result,ADC_Data;

LPC_ADC->CR &= ~(0xFF<<0); //clearing the Channel already used ADC0 in SEL bit of CR

LPC_ADC->CR |= (1 << 24) | (1 << channelNum); // switch channel using SEL,start A/D convert */

do { adc_result = LPC_ADC->DR[channelNum]; //Getting channel0's data register value in adc_result variable

/* read result of A/D conversion */

//Note:-Here the ADC_DONE macro value is 0x80000000

}while((adc_result & ADC_DONE)==0); //Waiting for ADC_DONE=1.[i.e DR value to become 0x8]

LPC_ADC->CR &= ~(7<<24); // stop ADC now (i.e.)CR[26:24]=000

ADC_Data = ( adc_result >> 4 ) & 0xFFF; //Getting adc converted result from 4th to 15th bit of DR

return ( ADC_Data );

}

Reading friends help me to clear the bug and execute as well.

Thanks in advance.