ADC in ATmega8

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Hello,
I am doing a project using ATmega8. For that we need an ADC of atleast
5Msps. We first thought of using the built in ADC but I want to know
the maximum samples per second for the in built ADC? I guess it is
around 150Ksps but I am not sure. Can I increase this sample rate by
loading the prescalar value like one or 2? Could someone help.
Thanks
with regards


Re: ADC in ATmega8



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Max is about 15 Ksps. The max sample-clock rate is 200 KHz at full
resolution and each conversion requires 13 sample clocks.

Given that the ATmega8 tops out at 16 MHz, trying to handle a 5 Msps
ADC directly might be rather ambitious.

--
Rich Webb   Norfolk, VA

Re: ADC in ATmega8


Would you like to give me any suggestions? What we are planning is that
we will use an adc to sample out the analog signal and then stored into
the memory of the microcontroller. It will then sent to the processor
for display on the screen using VGA programming. Everything is working
fine but we searching for the ADC. Any idea to work this out?
Regards


Re: ADC in ATmega8



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I'd start with Digikey, Mouser, and Newark to see what's actually
available to buy. From Digikey, assuming that 10 bits is enough (based
on your suggestion that the ADC in the ATmega8 was sufficient but slow)
and that you need at least 5 Msps then the answer is: TI's THS10082IDA.

An AVR is a nice processor but it's not really designed to sling data
around at that rate, certainly not on its own. A supporting CPLD or
small FPGA may give you enough throughput. Otherwise, I'd look at one of
the ARM-core processors.

--
Rich Webb   Norfolk, VA

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