ATmega128A Atmel Corporation, ATmega128A Datasheet - Page 248

• Manufacturer Part Number: ATmega128A
• Manufacturer: Atmel Corporation

Specifications of ATmega128A

• Flash (kbytes): 128 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 53
• Ext Interrupts: 8
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Uart: 2
• 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): 4
• Eeprom (bytes): 4096
• 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: 4
• Output Compare Channels: 8
• Input Capture Channels: 2
• Pwm Channels: 7
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

23.9.3
23.9.3.1
23.9.3.2
8151H–AVR–02/11
ADCL and ADCH - The ADC Data Register
ADLAR = 0:
ADLAR = 1:
• 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 23-5.
When an ADC conversion is complete, the result is found in these two registers. If differential
channels are used, the result is presented in two’s complement form.
When ADCL is read, the ADC Data Register is not updated until ADCH is read. Consequently, if
the result is left adjusted and no more than 8-bit precision is required, it is sufficient to read
ADCH. Otherwise, ADCL must be read first, then ADCH.
The ADLAR bit in ADMUX, and the MUXn bits in ADMUX affect the way the result is read from
the registers. If ADLAR is set, the result is left adjusted. If ADLAR is cleared (default), the result
is right adjusted.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
ADPS2
0
0
0
0
1
1
1
1
ADC Prescaler Selections
ADC7
ADC9
ADC1
15
15
R
R
R
R
–
7
0
0
7
0
0
ADC6
ADC8
ADC0
14
14
R
R
R
R
ADPS1
–
6
0
0
6
0
0
0
0
1
1
0
0
1
1
ADC5
ADC7
13
13
R
R
–
5
0
0
R
R
–
5
0
0
ADC4
ADC6
12
12
R
R
–
4
0
0
R
R
–
4
0
0
ADPS0
0
1
0
1
0
1
0
1
ADC3
ADC5
11
11
R
R
–
3
0
0
R
R
–
3
0
0
ADC2
ADC4
10
10
R
R
–
2
0
0
R
R
–
2
0
0
ADC9
ADC1
ADC3
ATmega128A
Division Factor
R
R
9
1
0
0
R
R
9
–
1
0
0
128
16
32
64
2
2
4
8
ADC0
ADC8
ADC2
R
R
8
0
0
0
R
R
8
–
0
0
0
ADCH
ADCL
ADCH
ADCL
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