Hello all,
On a model with separate analog gnd, analog power supply pins, i would expect from a chip proper operation for the stated ADC resolution. why there is a need for such a mode, if it is inevitable to enter such a mode for real 10bit, it is still fare to call the ADC peripheral 10bit?
Also I find something strange in the datasheet of the new ATmega164/324/644 devices, it is stated that, if the differential inputs with gain block are used, and 1x or 10x gain is selected, 8bit resolution can be expected and if 200x gain is selected, 7bit resolution can be expexted.
My question is then what will be the advantage of using the analog gain block???
While working with atmega48 device, i detected that when the ADC port is configured for IO operation, this ports use the analog vcc rail to push the pin to high level, which will surely effect analog measurements. So you better put high activity digital pins not on this port.
Regards
Murat Karadeniz
Thomas Keller wrote:
On Sat, 2005-10-22 at 10:22 -0700, Larry Barello wrote:
> That brings up a question: Does anyone use the noise cancelling mode
> and
> does it make a significant difference? How much of a difference?
I cannot claim to have actuallyused the mode, but as I understand the
literature, I would expect it to maske a fairly significant difference
for fine measurements. It essentially shuts down the remainder of the
digital circutiry on the chip, reducing the switching noise on the
internal Vcc bus (as well as on the reference voltage).
Tom
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