2008-04-13 09:15 AM
ADC conversion time
2011-05-17 03:29 AM
Dear Friends,
How to caculate ADC conversion time based upon clock.Because conversion time differed by clk.It was mentioned in datasheet for Example Freq: 56 MHZ -1 us 72 MHZ -1.17us pls explain and give the formula for this calculation Thank you2011-05-17 03:29 AM
This is very easy. One channel ADC conversion time takes APB 14 cycles,
with a maximum clock entry of 14MHz to the analog part. so depending on your ADC prescaler then APB to CPU clock ratio you will get the formula. 56 is a multiple of 14 so the calculation is easy and you get 1µs. You can also use both ADCs and you can reduce this conversion time to 500ns only. I suggest you to get a look on RM0008 document , then ADC section for more details. Cheers, STOne-32.2011-05-17 03:29 AM
Thank you for your immediate reply
your point is If we are working on 56MHZ Adc clock =56MHz(CPU clock)/((ADC Prescalar)4)=14MHz But If we are working on 72MHz Adc clock =72MHz(CPU clock)/(((ADC Prescalar)6)=12MHz Because of changes in ADC clock frequency differences are there in ADC conversion time. Note: 1.ADC prescalar dividers values are ->2,4,6,8 2.500ns conversion time is possible only in if we have two ADC's using the method of Dual sampling. Pls check this and let me know if i made any mistake in this. Thank you Warm Regards, Jeyakumar.R2011-05-17 03:29 AM
I believe that you find it out :) this time.