Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
248
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
Figure 24-13. Differential Non-linearity (DNL)
Quantization Error: Due to the quantization of the input voltage into a finite number of codes, a range of
input voltages (1 LSB wide) will code to the same value. Always ±0.5 LSB.
input voltages (1 LSB wide) will code to the same value. Always ±0.5 LSB.
Absolute accuracy: The maximum deviation of an actual (unadjusted) transition compared to an ideal
transition for any code. This is the compound effect of offset, gain error, differential error, non-linearity, and
quantization error. Ideal value: ±0.5 LSB.
transition for any code. This is the compound effect of offset, gain error, differential error, non-linearity, and
quantization error. Ideal value: ±0.5 LSB.
24.7
ADC Conversion Result
After the conversion is complete (ADIF is high), the conversion result can be found in the ADC Result Registers
(ADCL, ADCH).
(ADCL, ADCH).
For single ended conversion, the result is
where V
IN
is the voltage on the selected input pin and V
REF
the selected voltage reference (see
and
). 0x000 represents analog ground, and 0x3FF represents the selected
reference voltage minus one LSB.
24.8
Temperature Measurement
The temperature measurement is based on an on-chip temperature sensor that is coupled to a single ended
ADC8 channel. Selecting the ADC8 channel by writing the MUX3...0 bits in ADMUX register to "1000" enables
the temperature sensor. The internal 1.1V voltage reference must also be selected for the ADC voltage
reference source in the temperature sensor measurement. When the temperature sensor is enabled, the ADC
converter can be used in single conversion mode to measure the voltage over the temperature sensor.
ADC8 channel. Selecting the ADC8 channel by writing the MUX3...0 bits in ADMUX register to "1000" enables
the temperature sensor. The internal 1.1V voltage reference must also be selected for the ADC voltage
reference source in the temperature sensor measurement. When the temperature sensor is enabled, the ADC
converter can be used in single conversion mode to measure the voltage over the temperature sensor.
The measured voltage has a linear relationship to the temperature as described in
. The voltage
sensitivity is approximately 1 mV/°C and the accuracy of the temperature measurement is +/- 10°C.
The values described in
are typical values. However, due to the process variation the temperature
sensor output voltage varies from one chip to another. To be capable of achieving more accurate results the
Output Code
0x3FF
0x000
0
V
REF
Input Voltage
DNL
1 LSB
ADC
V
IN
1024
V
REF
--------------------------
=
Table 24-2.
Temperature vs. Sensor Output Voltage (Typical Case)
Temperature /
C
-45
C
+25
C
+85
C
Voltage / mV
242mV
314mV
380mV