ATMEGA649 datasheet(215/375 Pages) ATMEL

215 / 375 page

215

ATmega329/3290/649/6490

2552H–AVR–11/06

ADMUX – ADC Multiplexer

Selection Register

• Bit 7:6 – REFS1:0: Reference Selection Bits

These bits select the voltage reference for the ADC, as shown in Table 95. If these bits

are changed during a conversion, the change will not go in effect until this conversion is

complete (ADIF in ADCSRA is set). The internal voltage reference options may not be

used if an external reference voltage is being applied to the AREF pin.

•

Bit 5 – ADLAR: ADC Left Adjust Result

The ADLAR bit affects the presentation of the ADC conversion result in the ADC Data

adjusted. Changing the ADLAR bit will affect the ADC Data Register immediately,

regardless of any ongoing conversions. For a complete description of this bit, see

“ADCL and ADCH – The ADC Data Register” on page 218.

• Bits 4:0 – MUX4:0: Analog Channel Selection Bits

The value of these bits selects which combination of analog inputs are connected to the

ADC. See Table 96 for details. If these bits are changed during a conversion, the

change will not go in effect until this conversion is complete (ADIF in ADCSRA is set).

Bit

7654

321

(0x7C)

REFS1

REFS0

ADLAR

MUX4

MUX3

MUX2

MUX1

MUX0

ADMUX

Read/Write

R/W

Initial Value

0000

000

Table 95. Voltage Reference Selections for ADC

REFS1

REFS0

Voltage Reference Selection

AREF, Internal Vref turned off

AVCC with external capacitor at AREF pin

Reserved

Internal 1.1V Voltage Reference with external capacitor at AREF pin

ATMEGA649 Datasheet(PDF) 215 Page - ATMEL Corporation

ATMEGA649 Datasheet(HTML) 215 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL