ATmega8A Atmel Corporation, ATmega8A Datasheet - Page 210

• Manufacturer Part Number: ATmega8A
• Manufacturer: Atmel Corporation

Specifications of ATmega8A

• Flash (kbytes): 8 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 23
• Ext Interrupts: 2
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Pwm Channels: 3
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

22.8.3
22.8.3.1
8159D–AVR–02/11
ADCL and ADCH – The ADC Data Register
ADLAR = 0
• Bit 5 – ADFR: ADC Free Running Select
When this bit is set (one) the ADC operates in Free Running mode. In this mode, the ADC sam-
ples and updates the Data Registers continuously. Clearing this bit (zero) will terminate Free
Running mode.
• Bit 4 – ADIF: ADC Interrupt Flag
This bit is set when an ADC conversion completes and the Data Registers are updated. The
ADC Conversion Complete Interrupt is executed if the ADIE bit and the I-bit in SREG are set.
ADIF is cleared by hardware when executing the corresponding interrupt Handling Vector. Alter-
natively, ADIF is cleared by writing a logical one to the flag. Beware that if doing a Read-Modify-
Write on ADCSRA, a pending interrupt can be disabled. This also applies if the SBI and CBI
instructions are used.
• Bit 3 – ADIE: ADC Interrupt Enable
When this bit is written to one and the I-bit in SREG is set, the ADC Conversion Complete Inter-
rupt is activated.
• Bits 2:0 – ADPS2:0: ADC Prescaler Select Bits
These bits determine the division factor between the XTAL frequency and the input clock to the
ADC.
Table 22-4.
Bit
Read/Write
Initial Value
ADPS2
0
0
0
0
1
1
1
1
ADC7
ADC Prescaler Selections
15
R
R
–
7
0
0
ADC6
14
R
R
–
6
0
0
ADPS1
0
0
1
1
0
0
1
1
ADC5
13
R
R
–
5
0
0
ADC4
12
R
R
–
4
0
0
ADPS0
0
1
0
1
0
1
0
1
ADC3
11
R
R
–
3
0
0
ADC2
10
R
R
–
2
0
0
ADC9
ADC1
Division Factor
R
R
9
1
0
0
ATmega8A
128
16
32
64
2
2
4
8
ADC8
ADC0
R
R
8
0
0
0
ADCH
ADCL
210