DocID022945 Rev 5

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AN4073

Firmware techniques for improving the conversion accuracy

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Figure 3. Averaging of N-X ADC sample algorithm

Total conversion time = (number of samples * ADC conversion time) + computation time.

Computation time = time taken to read the results, sort the N ADC samples, delete the X

most dispersed samples, add the rest of the ADC samples together and calculate the

average by dividing the total by N-X.

Note:

Refer to Appendix B for more details about the code source used.

MS31177V1

Start

Initialize ADC, variables, I/O and select the

analog channel to be used, (Buff[N])

Configure the ADC to convert

once after each trigger

Set the ADC Start of Conversion bit

Read the ADC output registers after End of Conversion

Add read value to Buff[++]

No. of

conversions

= N?

Sort the N ADC sample

(sort Buff[N])

End

Yes

No

Delete X/2 sample from the top of Buff[N]

And X/2 sample from the bottom of Buff[N]

N-

_

2

X

-1

()

_

2

X

Buff[i]

()

N - X

1

Average =