C8051F800DK Silicon Laboratories Inc, C8051F800DK Datasheet - Page 58

• Manufacturer Part Number: C8051F800DK
• Description: KIT DEV C8051F800
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F800DK

• Contents: Board, Cables, CD, Debugger, Power Supply
• Processor To Be Evaluated: C8051F800
• Data Bus Width: 16 bit
• Interface Type: USB
• Operating Supply Voltage: 7 V to 15 V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F8xx
• Lead Free Status / Rohs Status: Supplier Unconfirmed
• Other names: 336-1797

C8051F80x-83x
9. Temperature Sensor
An on-chip temperature sensor is included on the C8051F800/1/2/3/4/5, C8051F812/3/4/5/6/7,
C8051F824/5/6, and C8051F830/1/2 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 be
configured to connect to the temperature sensor. The temperature sensor transfer function is shown in
Figure 9.1. The output voltage (V
The TEMPE bit in register REF0CN enables/disables the temperature sensor, as described in SFR Defini-
tion 10.1. While disabled, the temperature sensor defaults to a high impedance state and any ADC mea-
surements performed on the sensor will result in meaningless data. Refer to Table 7.11 for the slope and
offset parameters of the temperature sensor.
9.1. Calibration
The uncalibrated temperature sensor output is extremely linear and suitable for relative temperature mea-
surements (see Table 5.1 for linearity specifications). For absolute temperature measurements, offset
and/or gain calibration is recommended. Typically a 1-point (offset) calibration includes the following steps:
1. Control/measure the ambient temperature (this temperature must be known).
2. Power the device, and delay for a few seconds to allow for self-heating.
3. Perform an ADC conversion with the temperature sensor selected as the ADC’s input.
4. Calculate the offset characteristics, and store this value in non-volatile memory for use with subsequent
Figure 5.3 shows the typical temperature sensor error assuming a 1-point calibration at 0 °C.
Parameters that affect ADC measurement, in particular the voltage reference value, will also affect temper-
ature measurement.
58
temperature sensor measurements.
Figure 9.1. Temperature Sensor Transfer Function
V
Temp
TEMP
TEMP
C
=
) is the positive ADC input when the ADC multiplexer is set correctly.
= (V
(Slope
TEMP
x Temp
- Offset) /
Temperature
Rev. 1.0
C
) +
Offset
Slope
Offset
(V at 0 Celsius)
Slope
(V / deg C)