ADC conversion time doubts

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ADC conversion time doubts

750 Views
DeepakKukreja
Contributor III

Hi,

I am using Kinetis K12 device MK12DN512VLK5.

I have few doubts regarding the ADC conversion time calculations given in the reference manual.

The reference manual provides the below formula for calculating the conversion time:

pastedImage_5.png

I understand that the above formula gives the total time for conversion and takes into account the

  • sampling time,
  • ADC conversion time as well as the
  • time required for averaging if that is selected.

Is my understanding correct?

My doubt arises because of the example time calculation shown in the reference manual:

pastedImage_8.png

My calculation for the above example (based on the formula given in the reference manual) comes to 1731.625 micro-seconds.

time = "3 ADCK cycles" + "5 bus clock cycles" + (32 x "34+20 ADCK cycles" )

ADCK clock cycle time is 1.000 uSec ( from ADCk freq. = 8 MHz/8 )

Bus  clock cycle time is 0.125 uSec ( from 8 Mhz bus clock frequency)

I am misunderstanding something or is this an issue in the reference manual?

1 Reply

689 Views
nxf56274
NXP Employee
NXP Employee

Hi,

The document has some mistakes. Your calculation is right.

Have a great day,
TIC

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