If I'm limited to circa 200us per sample I may be as well using a ...
An ADC conversion takes 104 uS, and you can do it asynchronously. That is, do other stuff in the meantime.
If I run async what am I going to get?
If I'm working out how fast I can sample a obviously need to take the worst case figure, where did you get 104?
Is that an empirical result?
What is the accuracy of the result when running async ?
I doubt that they would have provided separate clocks and means to shut down the rest of the chip if it did not make a significant difference.
Now the ADC is 10b with 2LSB of error in quiet mode. That's 9 bit accuracy ADC. If I run async what am I going to get?
13/125000*1000000 ...13 clock cycles / 125000 clock cycles per second * 1000000 microseconds per second.
So why does the atmel spec sheet say 35 to 250 us, are you saying they are incorrect?
Are you being serious??
So why does the atmel spec sheet say 35 to 250 us
Where do you get your stated 13 cycles from?
A normal conversion takes 13 ADC clock cycles. The first conversion after the ADC is switchedon (ADEN in ADCSRA is set) takes 25 ADC clock cycles in order to initialize the analog circuitry.
ADC on these chips is succ. approx, the time to convert depends upon the data.
A normal conversion takes 13 ADC clock cycles.
Since the ADC cct has its own clock this conversion time probably does not even depend on what the main clock rate is set to.
Bits 2:0 - ADPS2:0: ADC Prescaler Select BitsThese bits determine the division factor between the system clock frequency and the input clock to the ADC.
I strongly suggest you read the data sheet before insulting people here, lest trouble falls.
QuoteAre you being serious??Are you being a troll?RTFM.QuoteSo why does the atmel spec sheet say 35 to 250 usIt doesn't; it says 13 to 260us
@OP, a successive approximation A-to-D consists of a D-to-A and a comparator.The conversion is essentially a binary chop, starting with the MSB, and it necessarily has to perform at least as many comparison cycles as there are bits to be converted.
That's complete nonsense. Read the datasheet: