lord loh.
Member
I am new to AVR and would like to use the AVR's ADc fecility. I am using the ATmega8535.
I do not follow the AVcc and AREF concepts.
The AVcc seems to be just as a feature to provide a seperate supply for the ADC. Altough, the ADC also requires 5V. The same as the AVR. So it is alright if I connect the AVcc to the Vcc and decouple it to the GND?
The Aref seems the ADC reference voltage. The datasheet mentions that there is an internal reference voltage of 2.56v. So If I do not bother with the Vref, is it okay? Should I decouple it to the ground?
I need to measure the temperature using an LM35 sensor. I am supplying the LM35 with 5v as well... So my output voltage can be around from -1v to 5v according to the datasheet of LM35. So I guess my Aref should be +5v and I cannot simply decouple it to the ground and forget all about it.
Am I correct?
I was also wondering what values shall I obtain the ADC registers if
I do not follow the AVcc and AREF concepts.
The AVcc seems to be just as a feature to provide a seperate supply for the ADC. Altough, the ADC also requires 5V. The same as the AVR. So it is alright if I connect the AVcc to the Vcc and decouple it to the GND?
The Aref seems the ADC reference voltage. The datasheet mentions that there is an internal reference voltage of 2.56v. So If I do not bother with the Vref, is it okay? Should I decouple it to the ground?
I need to measure the temperature using an LM35 sensor. I am supplying the LM35 with 5v as well... So my output voltage can be around from -1v to 5v according to the datasheet of LM35. So I guess my Aref should be +5v and I cannot simply decouple it to the ground and forget all about it.
Am I correct?
I was also wondering what values shall I obtain the ADC registers if
- Analog voltage is below GND?
- Analog voltage is above Aref?