C8051T602 View Datasheet(PDF) - Silicon Laboratories
Part Name
Description
MFG CO.
'C8051T602' PDF : 168 Pages View PDF
C8051T600/1/2/3/4/5/6
10. Temperature Sensor (C8051T600/2/4 only)
An on-chip temperature sensor is included on the C8051T600/2/4, which can be directly accessed via the
ADC multiplexer. To use the ADC to measure the temperature sensor, the ADC mux channel should be
configured to connect to the temperature sensor. The temperature sensor transfer function is shown in
Figure 10.1. The output voltage (VTEMP) is the positive ADC input when the ADC multiplexer is set cor-
rectly. The TEMPE bit in register REF0CN enables/disables the temperature sensor, as described in SFR
Definition 11.1. While disabled, the temperature sensor defaults to a high impedance state and any ADC
measurements performed on the sensor will result in meaningless data. Refer to Table 8.8 for the slope
and offset parameters of the temperature sensor.
VTEMP = ( Slope x TempC ) + Offset
TempC = (VTEMP - Offset) / Slope
Slope V/ (° C)
Offset (V at 0° C)
Temperature
Figure 10.1. Temperature Sensor Transfer Function
10.1. Calibration
The uncalibrated temperature sensor output is extremely linear and suitable for relative temperature mea-
surements (see Table 8.8 on page 35 for specifications). For absolute temperature measurements, offset
and/or gain calibration is recommended. A single-point offset measurement of the temperature sensor is
performed on each device during production test. The registers TOFFH and TOFFL, shown in SFR Defini-
tion 10.1 and SFR Definition 10.2 represent the output of the ADC when reading the temperature sensor at
0 °C, and using the internal regulator as a voltage reference.
Figure 10.2 shows the typical temperature sensor error assuming a 1-point calibration at 0 °C. Parame-
ters that affect ADC measurement, in particular the voltage reference value, will also affect temper-
ature measurement.
52
Rev. 1.2
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