Hi,I need to use all of the 8-bit ADC channels of the LPC935/6. Right now it is working fine with 3 of them. Channels AD10, AD11, AD12. But when I select the last channel AD13 it (AD13, P0.4) does not give me a result. It gives a negative number. I have tried using only AD13 and does not work. I am using the same power supply for all ADC channel inputs, but I use different multipliers to get different results. I am using several peripherals in this program. (Timer & UART)
However, I have a pilot program where I am only using the ADC peripheral and all of them work fine (give me an expected result) ADC10-3.
I have tested these programs with different chips, EMP900 and the result is the same.
What could be wrong?
Can anyone help me? Erik?

I have selected AutoScan, Single conversion mode.

Here is copy of the program I am using:

        // channel 0
  	P0M1 |= 0x02;
  	P0M2 &= ~0x02;
	// channel 1
	P0M1 |= 0x04;
	P0M2 &= ~0x04;
	// channel 2
	P0M1 |= 0x08;
	P0M2 &= ~0x08;
	// channel 3
	P0M1 |= 0x10;
	P0M2 &= ~0x10;

:
'Call ADC1 to convert
void ConvertVal (void)
{
ADMODB |= 0x40;  // configure clock divider 3.3 MHZ or less
  	ADMODB &= ~0x08; // disable dac1
  	ADCON1 |= 0x04; // configure adc1 and enable 
	ADCON1 &= 0x8C;  // disable all triggers
  	ADINS |= 0xF0;   // Select all channels
	ADMODA |= 0x10;	 // select mode
  	ADCON1 |= 0x01;	 // select trigger
	while ((ADCON1 &0x08) == 0);
	V0 = AD1DAT0;
	V1 = AD1DAT1;
	V2 = AD1DAT2; 
	V3 = AD1DAT3;   // Not working, Not converting

	ADCON1 &= 0x8C;  // disable all triggers
	V1 = ((((V1/(255/5))*100)/91))*9;
	V0 = ((((V0/(255/5))*100)/91))*17;  
	V3 = ((((V3/(255/5))*100)/91))*3;//Gives Zero or -number
	V2 = ((((V2/(255/5))*100)/91))*50;// 250/5 
}