Content originally posted in LPCWare by alexxx on Tue Jun 25 23:31:01 MST 2013Hi!
I read ADC every 10ms, inside systick interrupt. It is ADC 0. The problem is that every now and then (something like once or twice in a minute), the ADC returns 0xFFF. I investigated with the oscilloscope, but there is nothing wrong with hardware line on ADC0. Has anyone experienced a similar problem? I am using LPC1763, IAR compiler. My code is:
void initialize_adc (void)
{
ADC_Init(LPC_ADC, 100000); //100KHz
ADC_IntConfig(LPC_ADC,ADC_ADINTEN0,DISABLE);
ADC_ChannelCmd(LPC_ADC,ADC_CHANNEL_0,ENABLE);
}
unsigned int return_adc_channel ( const unsigned char CHANNEL_SETUP ) //CHANNEL_SETUP is always 0 for this project
{
_UINT temp;<span class="Apple-tab-span" style="white-space: pre;"> </span>//this is a union
// Start conversion
ADC_StartCmd(LPC_ADC,ADC_START_NOW);
//Wait conversion complete
while (!(ADC_ChannelGetStatus(LPC_ADC,CHANNEL_SETUP,ADC_DATA_DONE)));
//get ADC data
temp.ivalue = ADC_ChannelGetData(LPC_ADC,CHANNEL_SETUP);
return temp.ivalue;
}
So the problem is that this temp.ivalue returns a 0xFFF, but the voltage on ADC0 doesn't change. After this faulty measurement in the next ADC conversion, the returned value is again OK.
