I need to take very fast ADC measurements. Reading the datasheet of the ATmega48PA I see that the ADC measurement needs 13 CPU clock to be executed. Also for 10bits measurements the ADC peripheral clock must be in the range of 50 to 200KHz and for 8bit measurements it can be more than 200KHz.
Having a crystal of 8MHz the minimum time for 10bit measurements is 8MHz / 64 (prescaller) = 125KHz, 1 / 125KHz = 8usec and 8usec * 13 (clocks) = 104usec
Is there any mistake on my calculations?
To be faster, I could switch to 8 bit measurements, but there is no definitions in the datasheet of which could be the Maximum ADC peripheral clock? The only thing I see is that it can be >200KHz