ATMEGA8L-8AUR Atmel, ATMEGA8L-8AUR Datasheet - Page 190

• Manufacturer Part Number: ATMEGA8L-8AUR
• Description: MCU AVR 8KB FLASH 8MHZ 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8L-8AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 23
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Package: 32TQFP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 8 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 23
• Interface Type: SPI/TWI/USART
• On-chip Adc: 8-chx10-bit
• Number Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

190
ATmega8(L)
Figure 90. Analog to Digital Converter Block Schematic Operation
The ADC converts an analog input voltage to a 10-bit digital value through successive approxi-
mation. The minimum value represents GND and the maximum value represents the voltage on
the AREF pin minus 1 LSB. Optionally, AV
nected to the AREF pin by writing to the REFSn bits in the ADMUX Register. The internal
voltage reference may thus be decoupled by an external capacitor at the AREF pin to improve
noise immunity.
The analog input channel is selected by writing to the MUX bits in ADMUX. Any of the ADC input
pins, as well as GND and a fixed bandgap voltage reference, can be selected as single ended
inputs to the ADC. The ADC is enabled by setting the ADC Enable bit, ADEN in ADCSRA. Volt-
age reference and input channel selections will not go into effect until ADEN is set. The ADC
does not consume power when ADEN is cleared, so it is recommended to switch off the ADC
before entering power saving sleep modes.
The ADC generates a 10-bit result which is presented in the ADC Data Registers, ADCH and
ADCL. By default, the result is presented right adjusted, but can optionally be presented left
adjusted by setting the ADLAR bit in ADMUX.
AREF
ADC7
ADC6
ADC5
ADC4
ADC3
ADC2
ADC1
ADC0
AVCC
GND
INTERNAL 2.56V
REFERENCE
REFERENCE
BANDGAP
8-BIT DATA BUS
INPUT
MUX
ADC MULTIPLEXER
SELECT (ADMUX)
MUX DECODER
CC
or an internal 2.56V reference voltage may be con-
10-BIT DAC
ADC CTRL. & STATUS
REGISTER (ADCSRA)
ADC CONVERSION
COMPLETE IRQ
CONVERSION LOGIC
PRESCALER
SAMPLE & HOLD
COMPARATOR
15
+
-
ADC DATA REGISTER
(ADCH/ADCL)
ADC MULTIPLEXER
OUTPUT
2486Z–AVR–02/11
0