CC2540 ADC conversion sequence

Checking ADCCON2[3:0] will only tell you which channel the conversion is currently at, not which is currently done.

It seems you will miss the first read-out of channel 1 and might end up with swapped storage of the data.

Using DMA is the cleanest way to do this, optionally you can skip the if() checking of channels and disable interrupts while doing measurements to ensure you read out the correct channel.

Regards,
Svend

Hi , Svend, thanks for your answer.

The EOC flag in ADCCON1  means the end of the one channle's conversion or  the end of the sequence's ( two channles) conversion ? 

When the ADCCON2.SCH bits are read, they indicate the channel on which conversion is ongoing. The
results in ADCL and ADCH normally apply to the previous conversion. If the conversion sequence has
ended, ADCCON2.SCH has a value of one more than the last channel number.

The result should be read  like this ?

while (!(ADCCON1 & 0x80));

if (ADCCON2 & 0x0F == 0x01) //AN0 result
{
adc_v0 = (int16) (ADCL);
adc_v0 |= (int16) (ADCH << 8);
}
else if (ADCCON2 & 0x0F == 0x02) //AN1 result
adc_v1 = (int16) (ADCL);
adc_v1 |= (int16) (ADCH << 8);
}

while (!(ADCCON1 & 0x80));

if (ADCCON2 & 0x0F == 0x02) //AN1 result
{
adc_v2 = (int16) (ADCL);
adc_v2 |= (int16) (ADCH << 8);

}
else if (ADCCON2 & 0x0F == 0x01) //AN0 result
{
adc_v3 = (int16) (ADCL);
adc_v3 |= (int16) (ADCH << 8);
adc =  (uint32)adc_v1 << 16 | adc_v3;
}

adc = (uint32)adc_v2 << 16 | adc_v0;

}

return adc;

Using DMA is  a good way. But i want to using ADC triggered by a timer (timer1 channle compare event), not the full speed conversion.  

ADCCON1[5:4] need to select 10 as timer 1 channel 0 compare event.

Then initial timer1, in this step, it should enable timer1 interrupt , if so, and what should be handle in the ISR ?

The question is some more .

Thank you for your patient reading.

BR,

Key

Thank you so much, Svend ! That's really helpful for me. I am trying to slove it.

Thanks !

BR,

Key