C8051F93X Datasheet, PDF (86/330 Pages) Silicon Laboratories – Pipelined intstruction architecture executes 70 of instruction in 1 or 2 system clocks

C8051F93x-C8051F92x
5.6. Temperature Sensor
An on-chip temperature sensor is included on the C8051F93x-C8051F92x which can be directly accessed
via the ADC multiplexer in single-ended configuration. To use the ADC to measure the temperature sensor,
the ADC mux channel should select the temperature sensor. The temperature sensor transfer function is
shown in Figure 5.8. The output voltage (V_TEMP) is the positive ADC input when the ADC multiplexer is set
correctly. The TEMPE bit in register REF0CN enables/disables the temperature sensor, as described in
SFR Definition 5.15. 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 4.9 for the
slope and offset parameters of the temperature sensor.
Important Note: Before switching the ADC multiplexer from another channel to the temperature sensor,
the ADC mux should select the 'Ground' channel as an intermediate step. The intermediate 'Ground'
channel selection step will discharge any voltage on the ADC sampling capacitor from the previous
channel selection. This will prevent the possibility of a high voltage (> 2V) being presented to the
temperature sensor circuit, which can otherwise impact its long-term reliability.
V_TEMP = Slope x (Temp_C - 25) +Offset
Temp_C = 25 + (V_TEMP - Offset) / Slope
Slope ( V / deg C)
Offset ( V at 25 Celsius)
Temperature
Figure 5.8. Temperature Sensor Transfer Function
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Rev. 1.3