AN1711 datasheet(7/40 Pages) STMICROELECTRONICS

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SOFTWARE TECHNIQUES FOR COMPENSATING ST7 ADC ERRORS

1.8 USING A 10-BIT ADC AS AN 8-BIT ADC

The EOC bit is cleared only when you read the ADCDRH. You can use the ADC in 8-bit mode

if you do not need 10-bit ADC resolution. Thus there is no need to read the ADCDRL register.

Here is the software flow:

1. Check for EOC

2. If EOC is set, read the ADCDRH. This clears the EOC bit.

3. Do not read the ADCDRL. It is not mandatory to read this register.

1.9 COMBINED REGISTER FOR CONTROL BITS AND LSB OF CONVERSION RESULT

Some ST7 devices have a single register containing both the 2 least significant bits of the con-

version result and by some control bits in the rest of the register. In this case you need to mask

the control bits to filter the 2 bits of the ADC conversion result.

1.10 ZOOMING TO LOW VOLTAGE SIGNALS

Some the ST7 devices (for example ST7LITE) have a built-in amplifier to amplify the input

signal. A control bit is available to switch the amplifier ON.

It is thus possible to zoom for lower voltages by switching the ADC amplifier ON and then

switching it OFF for higher voltages.

This is very useful for interfacing sensors directly connected to the ADC inputs.

AN1711 Scheda tecnica(PDF) 7 Page - STMicroelectronics