atmega48 adc at faster than best clock speeds
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From: Hul Tytus on 4 Feb 2010 16:57 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
From: Vladimir Vassilevsky on 4 Feb 2010 17:24 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
From: dbr on 5 Feb 2010 12:19
Thanks. That info should speed the testing. Hul Vladimir Vassilevsky <nospam(a)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 |