EasyManuals Logo

ST STM32L4x6 User Manual

ST STM32L4x6
1693 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #501 background imageLoading...
Page #501 background image
DocID024597 Rev 3 501/1693
RM0351 Analog-to-digital converters (ADC)
540
16.3.33 Monitoring the internal voltage reference
It is possible to monitor the internal voltage reference (V
REFINT
) to have a reference point for
evaluating the ADC V
REF+
voltage level.
The internal voltage reference is internally connected to the input channel 0 of the ADC1
(ADC1_IN0).
Refer to the electrical characteristics section of the STM32L4x6 datasheet for the sampling
time value to be applied when converting the internal voltage reference voltage.
Figure 127 shows the block diagram of the V
REFINT
sensing feature.
Figure 128. V
REFINT
channel block diagram
Note: The VREFEN bit into ADCx_CCR register must be set to enable the conversion of internal
channels ADC1_IN0 (V
REFINT
).
Calculating the actual V
DDA
voltage using the internal reference voltage
The V
DDA
power supply voltage applied to the microcontroller may be subject to variation or
not precisely known. The embedded internal voltage reference (V
REFINT
) and its calibration
data acquired by the ADC during the manufacturing process at V
DDA
= 3.3 V can be used to
evaluate the actual V
DDA
voltage level.
The following formula gives the actual V
DDA
voltage supplying the device:
V
DDA
= 3.0 V x VREFINT_CAL / VREFINT_DATA
Where:
VREFINT_CAL is the VREFINT calibration value
VREFINT_DATA is the actual VREFINT output value converted by ADC
Converting a supply-relative ADC measurement to an absolute voltage value
The ADC is designed to deliver a digital value corresponding to the ratio between the analog
power supply and the voltage applied on the converted channel. For most application use
cases, it is necessary to convert this ratio into a voltage independent of V
DDA
. For
applications where V
DDA
is known and ADC converted values are right-aligned you can use
the following formula to get this absolute value:
For applications where V
DDA
value is not known, you must use the internal voltage
reference and V
DDA
can be replaced by the expression provided in Section : Calculating the
069
9
5(),17
$'&
$'&B,1
$'&B95()(1
FRQWUROELW
,QWHUQDO
SRZHUEORFN
V
CHANNELx
V
DDA
FULL_SCALE
-------------------------------------
ADCx_DATA×=

Table of Contents

Questions and Answers:

Question and Answer IconNeed help?

Do you have a question about the ST STM32L4x6 and is the answer not in the manual?

ST STM32L4x6 Specifications

General IconGeneral
BrandST
ModelSTM32L4x6
CategoryMicrocontrollers
LanguageEnglish

Related product manuals