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atmega48 adc at faster than best clock speeds

Started by Hul Tytus February 4, 2010
comp.arch.embedded
atmega48 adc at faster than best clock speeds

	Atmel's atmega48 manual states the adc clock should run between 100 
kcs & 200 kcs for best, most accurate conversions. They also state that higher 
clock rates can be used, presumably when a higher sampling rate is to greater 
advantage than best accuracy.
	Has anyone checked the accuracy of these converters when used with 
higher clock rates? If so, could you show the results here?

Hul

Hul Tytus wrote:

> comp.arch.embedded > atmega48 adc at faster than best clock speeds > > Atmel's atmega48 manual states the adc clock should run between 100 > kcs & 200 kcs for best, most accurate conversions. They also state that higher > clock rates can be used, presumably when a higher sampling rate is to greater > advantage than best accuracy. > Has anyone checked the accuracy of these converters when used with > higher clock rates? If so, could you show the results here?
According to the datasheet, the max. clock rate for AVR ADC is 1 MHz, although they recommend 100-200KHz for best results, as you noted. I have actually used ADC at 625 KHz clock in a single channel mode. I didn't check the accuracy or SNR specifically, however it looked like it worked no different from usual. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Thanks.  That info should speed the testing.

Hul

Vladimir Vassilevsky <nospam@nowhere.com> wrote:
> Hul Tytus wrote: > > comp.arch.embedded > > atmega48 adc at faster than best clock speeds > > > > Atmel's atmega48 manual states the adc clock should run between 100 > > kcs & 200 kcs for best, most accurate conversions. They also state that higher > > clock rates can be used, presumably when a higher sampling rate is to greater > > advantage than best accuracy. > > Has anyone checked the accuracy of these converters when used with > > higher clock rates? If so, could you show the results here?
> According to the datasheet, the max. clock rate for AVR ADC is 1 MHz, > although they recommend 100-200KHz for best results, as you noted. I > have actually used ADC at 625 KHz clock in a single channel mode. I > didn't check the accuracy or SNR specifically, however it looked like it > worked no different from usual.
> Vladimir Vassilevsky > DSP and Mixed Signal Design Consultant > http://www.abvolt.com