AN1711 datasheet(14/40 Pages) STMICROELECTRONICS

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SOFTWARE TECHNIQUES FOR COMPENSATING ST7 ADC ERRORS

Figure 7. Histogram technique Flowchart

Practical measurement

You can test this technique using a hardware setup similar to the one shown in Figure 8. The

eliminated value was also captured on HyperTerminal. Only last eliminated value was dis-

played on HyperTerminal.

A Switch connected at a port pin was used to inform the software to send the data on SCI com-

munication. The port pin was configured as input and when, the switch was pressed ‘0’ is read

on this pin, the ADC readings were then sent to the PC using RS232 communication. These

readings were read on the HyperTerminal and noted.

A function generator is used in lab to introduce noise in the neighbouring pin of analog signal

being converted so as to generate the noisy conversions. This neighbouring pin is also config-

ured as floating input.

yes

Initialise ADC, variables, and select analog

START

Start ADC

Read the ADC output registers after End of Conversion

channel

Store the result in an Array

Array filled

Find the number of occurrences of each digital result

Reject the values occurring less than expected number

Take average

of other values

of times

AN1711 データシート(PDF) 14 Page - STMicroelectronics