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RM0351 Analog-to-digital converters (ADC)
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The data format must be 16-bit signed:
ADC_DR[15:12] = sign extended
ADC_DR[11] = sign
ADC_DR[10:0] = data
To obtain 16-bit signed format, the software needs to configure OFFSETy[11:0] bits to 0x800
after having set OFFSETy_EN to 1.
Only right aligned data can be provided to the DFSDM input format. (see Figure 97: Right
alignment (offset enabled, signed value))
DFSDM mode in dual ADC simultaneous mode
The dual mode is not required to use DFSDM in dual ADC simultaneous mode since
conversion data will be treated by each individual channel. Single mode with same trigger
source results in simultaneous conversion with DFSDM interface.
18.4.32 Temperature sensor
The temperature sensor can be used to measure the junction temperature (Tj) of the device.
The temperature sensor is internally connected to the ADC1_IN17 and ADC3_IN17 input
channels which are used to convert the sensor output voltage to a digital value. When not in
use, the sensor can be put in power down mode.
Figure 134 shows the block diagram of connections between the temperature sensor and
the ADC.
The temperature sensor output voltage changes linearly with temperature. The offset of this
line varies from chip to chip due to process variation (up to 45 °C from one chip to another).
The uncalibrated internal temperature sensor is more suited for applications that detect
temperature variations instead of absolute temperatures. To improve the accuracy of the
temperature sensor measurement, calibration values are stored in system memory for each
device by ST during production.
During the manufacturing process, the calibration data of the temperature sensor and the
internal voltage reference are stored in the system memory area. The user application can
then read them and use them to improve the accuracy of the temperature sensor or the
internal reference. Refer to the STM32L4x5/STM32L4x6 datasheet for additional
information.
Main features
• Supported temperature range: –40 to 125 °C
• Precision: ±2 °C
The temperature sensor is internally connected to the ADC1_IN17 and ADC3_IN17 input
channel which is used to convert the sensor’s output voltage to a digital value. Refer to the
electrical characteristics section of the device datasheet for the sampling time value to be
applied when converting the internal temperature sensor.
When not in use, the sensor can be put in power-down mode.
Figure 134 shows the block diagram of the temperature sensor.
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