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Atmel | SMART SAM D20 [DATASHEET]
Atmel-42129K–SAM-D20_datasheet–06/2014
32.8.8 Temperature Sensor Characteristics
32.8.8.1 Temperature Sensor Characteristics
Table 32-27. Temperature Sensor Characteristics
(1))
Note: 1. These values are based on characterization. These values are not covered by test limits in production.
2. See also rev C errata concerning the temperature sensor.
32.8.8.2 Software-based Refinement of the Actual Temperature
The temperature sensor behavior is linear but it depends on several parameters such as the internal voltage reference
which itself depends on the temperature. To take this into account, each device contains a Temperature Log row with
data measured and written during the production tests. These calibration values should be read by software to infer the
most accurate temperature readings possible.
This Software Temperature Log row can be read at address 0x00806030. The Software Temperature Log row cannot be
written.
This section specifies the Temperature Log row content and explains how to refine the temperature sensor output using
the values in the Temperature Log row.
Temperature Log Row
All values in this row were measured in the following conditions:
z V
DDIN
= V
DDIO
= V
DDANA
= 3.3V
z ADC Clock speed = 1MHz
z ADC mode: Free running mode, ADC averaging mode with 4 averaged samples
z ADC voltage reference = 1.0V internal reference (aka INT1V)
z ADC input = temperature sensor
Table 32-28. Temperature Log Row Content
Symbol Parameter Conditions Min. Typ. Max. Units
I
Temperature sensor output
voltage
T= 25°C, V
DDANA
= 3.3V - 0.667 - V
I
Temperature sensor slope 2.3 2.4 2.5 mV/°C
I
Variation over V
DDANA
voltage V
DDANA
=1.62V to 3.6V -1.7 1 3.7 mV/V
Bit Position Name Description
7:0 ROOM_TEMP_VAL_INT Integer part of room temperature in °C
11:8 ROOM_TEMP_VAL_DEC Decimal part of room temperature
19:12 HOT_TEMP_VAL_INT Integer part of hot temperature in °C
23:20 HOT_TEMP_VAL_DEC Decimal part of hot temperature
31:24 ROOM_INT1V_VAL
2’s complement of the internal 1V reference drift at room
temperature (versus a 1.0 centered value)