RM0440 Rev 4 685/2126
RM0440 Analog-to-digital converters (ADC)
724
By replacing V
REF+
by the formula provided above, the absolute voltage value is given by
the following formula
For applications where V
DDA
is known and ADC converted values are right-aligned, the
absolute voltage value can be obtained by using the following formula:
Where:
–V
DDA_Charac
is the value of V
DDA
voltage characterized at V
REFINT
during the
manufacturing process.
– VREFINT_CAL is the V
REFINT
calibration value
– ADC_DATA is the value measured by the ADC on channel x (right-aligned)
– VREFINT_DATA is the actual V
REFINT
output value converted by the ADC
– FULL_SCALE is the maximum digital value of the ADC output. For example with
12-bit resolution, it will be 2
12
- 1 = 4095 or with 8-bit resolution, 2
8
- 1 = 255.
Note: If ADC measurements are done using an output format other than 16-bit right-aligned, all
the parameters must first be converted to a compatible format before the calculation is
done.
21.5 ADC interrupts
For each ADC, an interrupt can be generated:
• After ADC power-up, when the ADC is ready (flag ADRDY)
• On the end of any conversion for regular groups (flag EOC)
• On the end of a sequence of conversion for regular groups (flag EOS)
• On the end of any conversion for injected groups (flag JEOC)
• On the end of a sequence of conversion for injected groups (flag JEOS)
• When an analog watchdog detection occurs (flag AWD1, AWD2 and AWD3)
• When the end of sampling phase occurs (flag EOSMP)
• When the data overrun occurs (flag OVR)
• When the injected sequence context queue overflows (flag JQOVF)
Separate interrupt enable bits are available for flexibility.
V
CHANNELx
V
DDA_Charac
VREFINT_CAL ADC_DATA××
VREFINT_DATA FULL_SCALE×
---------------------------------------------------------------------------------------------------------------------
=
V
CHANNELx
V
DDA
FULL_SCALE
-------------------------------------
ADC_DATA×=
Table 174. ADC interrupts per each ADC
Interrupt event Event flag Enable control bit
ADC ready ADRDY ADRDYIE
End of conversion of a regular group EOC EOCIE
End of sequence of conversions of a regular group EOS EOSIE
End of conversion of a injected group JEOC JEOCIE
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