ATMEGA8L ATMEL [ATMEL Corporation], ATMEGA8L Datasheet - Page 205

• Manufacturer Part Number: ATMEGA8L
• Description: 8-bit AVR with 8K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

The ADC Data Register – ADCL and ADCH
ADLAR = 0
ADLAR = 1
2486M–AVR–12/03
• 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 76. ADC Prescaler Selections
When an ADC conversion is complete, the result is found in these two registers.
When ADCL is read, the ADC Data Register is not updated until ADCH is read. Conse-
quently, 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.
• ADC9:0: ADC Conversion result
These bits represent the result from the conversion, as detailed in “ADC Conversion
Result” on page 202.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
ADPS2
0
0
0
0
1
1
1
1
ADC7
ADC9
ADC1
15
15
R
R
R
R
–
7
0
0
7
0
0
ADC6
ADC8
ADC0
14
14
ADPS1
R
R
R
R
–
6
0
0
6
0
0
0
0
1
1
0
0
1
1
ADC5
ADC7
13
13
R
R
R
R
–
5
0
0
–
5
0
0
ADC4
ADC6
12
12
–
4
R
R
0
0
–
4
R
R
0
0
ADPS0
0
1
0
1
0
1
0
1
ADC3
ADC5
11
11
R
R
R
R
–
3
0
0
–
3
0
0
ADC2
ADC4
10
10
R
R
R
R
–
2
0
0
–
2
0
0
ADC9
ADC1
ADC3
Division Factor
ATmega8(L)
R
R
R
R
9
1
0
0
9
–
1
0
0
128
16
32
64
2
2
4
8
ADC8
ADC0
ADC2
R
R
R
R
8
0
0
0
8
–
0
0
0
ADCH
ADCH
ADCL
ADCL
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