ATtiny461A Atmel Corporation, ATtiny461A Datasheet - Page 152

• Manufacturer Part Number: ATtiny461A
• Manufacturer: Atmel Corporation

Specifications of ATtiny461A

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.25
• Eeprom (bytes): 256
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

15.11 ADC Conversion Result
15.11.1
15.11.2
15.11.3
152
ATtiny261A/461A/861A
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 156
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
157). 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 156
NEG
IN
V
⋅
REF
) 1024
1024
157). 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
8197C–AVR–05/11