Overclocked
Member
Ive been trying to wrap my head around this, and for all intensive purposes I'll keep it generalized. All Micro's have some sort of internal ADC, and they all need a voltage reference in order to get the correct approximation of the voltage measured, ie
Vmeasured = (readvalue *500)/1024
For a 10Bit ADC and a Vref of 5V. However, what happens if you dont Know your voltage reference point? How would you calibrate it? If you only have the 10 bit number you read from the ADC, can you get the voltage reference? You can assume a ideal voltage reference of 5.00v, but whos to say it doesnt vary to 4.95 or 5.05V (without measuring-some micro's have a internal voltage reference).
Hopefully my question is clear, as the micro Im using has a internal voltage reference, but it ranges from -6% to +8%. The nominal voltage is 2.048V. Ive tried to come up with a ton of formula, but the closest Ive gotten only compensates if its less than the ideal, not more.
Vmeasured = (readvalue *500)/1024
For a 10Bit ADC and a Vref of 5V. However, what happens if you dont Know your voltage reference point? How would you calibrate it? If you only have the 10 bit number you read from the ADC, can you get the voltage reference? You can assume a ideal voltage reference of 5.00v, but whos to say it doesnt vary to 4.95 or 5.05V (without measuring-some micro's have a internal voltage reference).
Hopefully my question is clear, as the micro Im using has a internal voltage reference, but it ranges from -6% to +8%. The nominal voltage is 2.048V. Ive tried to come up with a ton of formula, but the closest Ive gotten only compensates if its less than the ideal, not more.