3.3 ADC Single Conversion
In this use case, the ADC runs in Single Conversion mode. It runs by
configuring the EXAMPLE_CODE definition to
SINGLE_CONVERSION in main.c
as:
#define EXAMPLE_CODE SINGLE_CONVERSIONThe conversion starts after the
‘read_adc_single_conversion()’ function is called.
The ‘ADC_0_get_conversion()’ function is then called, in
which ADC_COMMAND.STCONV is written to '1'. When the
conversion cycle is completed, the ADC data is converted to voltage format
which is printed through the USART to the terminal. One can choose to use
the terminal like the one already embedded in Data Visualizer in Atmel
Studio.
Since the ‘read_adc_single_conversion()’ function
is called continuously in the while(1) loop in the
‘main()’ function, a single conversion is manually
configured to start after the previous one is completed. This is why one can
observe that the calculated voltage is continuously printed to the terminal,
same behavior as in the Free-Running mode. The difference is that, in the
Free-Running mode, ADC_COMMAND.STCONV is only written to
'1' once when the
‘ADC_0_start_conversion()’ function is called
before the while(1) loop starts.
ADC_0_get_conversion(ADC_CHANNEL)’ function, which
reads the ADC data, is defined in adc_basics.c. It will be
redefined in the adc_windows.c file when the ADC Window
Compare mode is used and all related drivers will be updated in the
corresponding driver file adc_windows.c instead of
adc_basics.c.