8.12 Internal Temperature Sensor
The internal temperature sensor measures the junction temperature of the device. The sensor output can
be sampled with the ADC on channel A5 using a switch controlled by the ADCCTL1.TEMPCONV bit. The
switch allows A5 to be used both as an external ADC input pin and the temperature sensor access point.
When sampling the temperature sensor, the external circuitry on ADCINA5 has no affect on the sample. Refer
to
for information about switching between the external ADCINA5 input pin and the internal
temperature sensor.
8.12.1 Transfer Function
The temperature sensor output and the resulting ADC values increase with increasing junction temperature. The
offset is defined as the 0 °C LSB crossing as illustrated in
. This information can be used to convert
the ADC sensor sample into a temperature unit.
The transfer function to determine a temperature is defined as:
Temperature = (
sensor
- Offset) * Slope
Slope (°C/LSB)
LSB
Offset (0°C LSB value)
T
emperature
Figure 8-13. Temperature Sensor Transfer Function
Refer to the electrical characteristics section in the
TMS320F2806x Real-Time Microcontrollers Data Manual
the slope and offset, or use the stored slope and offset calibrated per device in the factory that can be extracted
by a function at the following locations.
For F2806x:
• 0x3D7E82 - Slope (°C / LSB, fixed-point Q15 format)
• 0x3D7E85 - Offset (0 °C LSB value)
The values listed are assuming a 3.3-V full-scale range. Using the internal reference mode automatically
achieves this fixed range, but if using the external mode, the temperature sensor values must be adjusted
accordingly to the external reference voltages.
Analog-to-Digital Converter (ADC)
532
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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