AT90PWM216-16SE ATMEL [ATMEL Corporation], AT90PWM216-16SE Datasheet - Page 250

• Manufacturer Part Number: AT90PWM216-16SE
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable flash
• Manufacturer: ATMEL [ATMEL Corporation]

250
AT90PWM216/316
These 2 bits determine the voltage reference for the ADC.
The different setting are shown in
Table 21-3.
If these bits are changed during a conversion, the change will not take effect until this conversion
is complete (it means while the ADIF bit in ADCSRA register is set).
In case the internal Vref is selected, it is turned ON as soon as an analog feature needed it is
set.
• Bit 5 – ADLAR: ADC Left Adjust Result
Set this bit to left adjust the ADC result.
Clear it to right adjust the ADC result.
The ADLAR bit affects the configuration of the ADC result data registers. Changing this bit
affects the ADC data registers immediately regardless of any on going conversion. For a com-
plete description of this bit, see Section “ADC Result Data Registers – ADCH and ADCL”,
page 253.
• Bit 3, 2, 1, 0 – MUX3, MUX2, MUX1, MUX0: ADC Channel Selection Bits
These 4 bits determine which analog inputs are connected to the ADC input. The different set-
ting are shown in
Table 21-4.
REFS1
0
0
1
1
MUX3
0
0
0
0
0
0
0
0
1
1
1
1
1
ADC Voltage Reference Selection
ADC Input Channel Selection
REFS0
0
1
0
1
MUX2
0
0
0
0
1
1
1
1
0
0
0
0
1
Table
21-4.
Description
External Vref on AREF pin, Internal Vref is switched off
AVcc with external capacitor connected on the AREF pin
Reserved
Internal 2.56V Reference voltage with external capacitor connected on
the AREF pin
MUX1
0
0
1
1
0
0
1
1
0
0
1
1
0
Table
21-3.
MUX0
0
1
0
1
0
1
0
1
0
1
0
1
0
Description
ADC0
ADC1
ADC2
ADC3
ADC4
ADC5
ADC6
ADC7
ADC8
ADC9
ADC10
AMP0
AMP1 (- is ADC8, + is ADC9)
7710D–AVR–08/09