ATA6613 ATMEL Corporation, ATA6613 Datasheet - Page 277

• Manufacturer Part Number: ATA6613
• Description: Ata6613
• Manufacturer: ATMEL Corporation

6.21.6
6.21.6.1
9111C–AUTO–02/08
ADC Conversion Result
ADC Multiplexer Selection Register – ADMUX
After the conversion is complete (ADIF is high), the conversion result can be found in the ADC
Result Registers (ADCL, ADCH).
For single ended conversion, the result is
where V
Table 6-98 on page 277
0x3FF represents the selected reference voltage minus one LSB.
Table 6-98.
ADC
• Bit 7:6 – REFS1:0: Reference Selection Bits
• Bit 5 – ADLAR: ADC Left Adjust Result
• Bit 4 – Res: Reserved Bit
• Bits 3:0 – MUX3:0: Analog Channel Selection Bits
REFS1
Initial Value
Read/Write
These bits select the voltage reference for the ADC, as shown in
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.
The ADLAR bit affects the presentation of the ADC conversion result in the ADC Data Reg-
ister. Write one to ADLAR to left adjust the result. Otherwise, the result is right 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” on page
This bit is an unused bit in the ATA6612/ATA6613, and will always read as zero.
The value of these bits selects which analog inputs are connected to the ADC. See
6-99 on page 278
not go in effect until this conversion is complete (ADIF in ADCSRA is set).
0
0
1
1
Bit
=
IN
V
---------------------------- -
IN
is the voltage on the selected input pin and V
V
REFS0
REF
Voltage Reference Selections for ADC
1024
REFS1
0
1
0
1
R/W
7
0
Voltage Reference Selection
AREF, Internal V
AV
Reserved
Internal 1.1V Voltage Reference with external capacitor at AREF pin
for details. If these bits are changed during a conversion, the change will
REFS0
CC
R/W
and
6
0
with external capacitor at AREF pin
Table 6-99 on page
280).
ADLAR
R/W
5
0
ref
turned off
R
4
–
0
278). 0x000 represents analog ground, and
MUX3
R/W
3
0
REF
ATA6612/ATA6613
the selected voltage reference (see
MUX2
R/W
2
0
Table
“The ADC Data Register –
MUX1
R/W
1
0
6-98. If these bits are
MUX0
R/W
0
0
ADMUX
Table
277