ATA5771_09 ATMEL [ATMEL Corporation], ATA5771_09 Datasheet - Page 201

• Manufacturer Part Number: ATA5771_09
• Description: Microcontroller with UHF ASK/FSK Transmitter
• Manufacturer: ATMEL [ATMEL Corporation]

18.8
18.8.1
18.8.2
148
ADC Conversion Result
ATtiny24/44/84
Single Ended Conversion
Unipolar Differential Conversion
Figure 18-12. Differential Non-linearity (DNL)
• Quantization Error: Due to the quantization of the input voltage into a finite number of codes, a
• Absolute Accuracy: The maximum deviation of an actual (unadjusted) transition compared to
After the conversion is complete (ADIF is high), the conversion result can be found in the ADC
Result Registers (ADCL, ADCH). The form of the conversion result depends on the type of the
conversio as there are three types of conversions: single ended conversion, unipolar differential
conversion and bipolar differential conversion.
For single ended conversion, the result is
where V
Table 18-3 on page 150
0x3FF represents the selected reference voltage minus one LSB. The result is presented in one-
sided form, from 0x3FF to 0x000.
If differential channels and an unipolar input mode are used, the result is
where V
and V
range of input voltages (1 LSB wide) will code to the same value. Always ± 0.5 LSB.
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.
REF
IN
POS
the selected voltage reference. The voltage of the positive pin must always be larger
is the voltage on the selected input pin and V
is the voltage on the positive input pin, V
Output Code
0x000
0x3FF
and
ADC
0
Table 18-4 on page
=
1 LSB
---------------------------------------------------------- -
V
ADC
POS
–
=
V
V
V
---------------------------- -
NEG
REF
IN
V
REF
151). 0x000 represents analog ground, and
1024
1024
NEG
REF
the voltage on the negative input pin,
the selected voltage reference (see
GAIN
V
REF
Input Voltage
7701C–AVR–12/08