Objective Development Forums

HI
I use AVR ATMEGA 16 ADC for 0-5V Voltmeter ! But ADC get me only 0xFF for all Voltage !
i link AREF and AVCC to VCC (5V) and with 1uf to ground !

i use CodevisionAVR for programming !

any body can help me ?

I have the same problem. i use ATmega 32 and 16. Tested with 7 devices on the same bord. 0xFF for all Voltage, for 0V on ADC0 too. I have tested the program on difrent PCB and it works.
I got AVCC linked to VCC. AVCC, AREF and VCC with 100nf to ground.

When I push the VCC from 5V to 5,3V the ADC starts to work. I got 0x00 with 0V on ADC0.

PS. Sorry for my english.

To high clock speed. You have to change ADPS bits in ADCSRA register. The ADC clock speed must be less then 200khz to work right.