atmega323l ATMEL Corporation, atmega323l Datasheet - Page 134

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

The ADC Data Register –
ADCL and ADCH
ADLAR = 0
ADLAR = 1
134
ATmega323(L)
• 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 47. 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 affects 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. $000 represents analog ground,
and $3FF represents the selected reference voltage minus one LSB.
Bit
$05 ($25)
$04 ($24)
Read/Write
Initial Value
Bit
$05 ($25)
$04 ($24)
Read/Write
Initial Value
ADPS2
0
0
0
0
1
1
1
1
ADC7
ADC9
ADC1
SIGN
15
15
R
R
R
R
7
0
0
7
0
0
ADC6
ADC8
ADC0
14
14
R
R
R
R
–
6
0
0
6
0
0
ADPS1
ADC5
ADC7
13
13
R
R
R
R
–
5
0
0
–
5
0
0
0
0
1
1
0
0
1
1
ADC4
ADC6
12
12
R
R
R
R
–
4
0
0
–
4
0
0
ADC3
ADC5
11
11
R
R
R
R
–
3
0
0
–
3
0
0
ADPS0
0
1
0
1
0
1
0
1
ADC2
ADC4
10
10
R
R
R
R
–
2
0
0
–
2
0
0
ADC9
ADC1
ADC3
R
R
R
R
9
1
0
0
9
–
1
0
0
Division Factor
ADC8
ADC0
ADC2
1457G–AVR–09/03
R
R
R
R
8
0
0
0
8
–
0
0
0
128
16
32
64
2
2
4
8
ADCH
ADCH
ADCL
ADCL