Voltage display

[Michael]

My first post, and greetings to all at his site,
I have been stuck on what may be an easy problem, but I haven't thus far found a good solution.

I am making a circuit , which most of is controlled by a ATmega32 chip. I realize there is a forum for chips, but this is more concerned with the surrounding circuity. The chip has 8 ports which can be used as ADC with 8 bit resolution. All I want to do is measure the voltage level on two lines.

Sounds easy you might say. However I have two problems. One I dont really want to sample at a very high rate which uses up much of the micro resources. And secondly the resolution I would like would be from around 15 - 20 dB to -40 or -50 dB .

OK, so what I thought was use two ADC for each line, one with an amplifier at the begining the other with reduction so the two ports would give a better range, each with with a sample and hold circuit leading into the ADC.

My problem is the circuit doesn't work to well, and well...any suggestions?

[MP]

Hi Michael, and welcome to the forum.

The code in the AtMega determines the rate of sample. I do not think there is a way to do this in hardware. Are you trying to get 20 bit resolution from a 10 bit ADC? It would be very helpful if you could post your circuit since it is a hardware question. With the limited understanding of your circuit, my first guess is that you need a faster clock on the micro.
Also, you would do much better posting in the micro area for this type of question. It is not only about firmware and chips, but hardware also.

MP