ATTINY261A-XUR Atmel, ATTINY261A-XUR Datasheet - Page 151

• Manufacturer Part Number: ATTINY261A-XUR
• Description: MCU AVR 2KB FLASH 20MHZ 20TSSOP
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY261A-XUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

15.11 ADC Conversion Result
15.11.1
15.11.2
15.11.3
8197B–AVR–01/10
Single Ended Conversion
Unipolar Differential Conversion
Bipolar Differential Conversion
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 15-4 on page 155
0x3FF represents the selected voltage reference 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
156). The voltage on the positive pin must always be larger than the voltage on the negative pin
or otherwise the voltage difference is saturated to zero. The result is presented in one-sided
form, from 0x000 (0d) to 0x3FF (+1023d). The GAIN is either 1x, 8x, 20x or 32x.
As default the ADC converter operates in the unipolar input mode, but the bipolar input mode
can be selected by writting the BIN bit in the ADCSRB to one. In the bipolar input mode two-
sided voltage differences are allowed and thus the voltage on the negative input pin can also be
larger than the voltage on the positive input pin. If differential channels and a bipolar input mode
are used, the result is
• Quantization Error: Due to the quantization of the input voltage into a finite number of codes,
• Absolute Accuracy: The maximum deviation of an actual (unadjusted) transition compared to
a 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 (see
is the voltage on the selected input pin and V
is the voltage on the positive input pin, V
and
ADC
Table 15-5 on page
=
(
------------------------------------------------------- - GAIN
ADC
V
POS
–
=
V
V
V
--------------------------
REF
Table 15-4 on page 155
NEG
IN
V
⋅
REF
) 1024
1024
156). 0x000 represents analog ground, and
⋅
NEG
REF
the voltage on the negative input pin,
⋅
the selected voltage reference (see
and
Table 15-5 on page
151