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258
8210C–AVR–09/11
Atmel AVR XMEGA D
• Bit 4 – CONVMODE: Conversion Mode
This bit controls whether the ADC will work in signed or unsigned mode. By default, this bit is
cleared and the ADC is configured for unsigned mode. When this bit is set, the ADC is config-
ured for signed mode.
• Bit 3 – FREERUN: Free Running Mode
This bit controls the free running mode for the ADC. Once a conversion is finished, the next input
will be sampled and converted.
• Bit 2:1 – RESOLUTION[1:0]: Conversion Result Resolution
These bits define whether the ADC completes the conversion at 12- or 8-bit result resolution.
They also define whether the 12-bit result is left or right adjusted within the 16-bit result regis-
ters. See
for possible settings.
• Bit 0 – Reserved
This bit is unused and reserved for future use. For compatibility with future devices, always write
this bit to zero when this register is written.
21.14.3
REFCTRL – Reference Control register
• Bit 7 – Reserved
This bit is unused and reserved for future use. For compatibility with future devices, always write
this bit to zero when this register is written.
Table 21-1.
ADC current limitations.
CURRLIMIT[1:0]
Group Configuration
Description
00
NO
No limit
01
LOW
Low current limit, max. sampling rate 1.5MSPS
10
MED
Medium current limit, max. sampling rate 1MSPS
11
HIGH
High current limit, max. sampling rate 0.5MSPS
Table 21-2.
ADC conversion result resolution.
RESOLUTION[1:0]
Group Configuration
Description
00
12BIT
12-bit result, right adjusted
01
Reserved
10
8BIT
8-bit result, right adjusted
11
LEFT12BIT
12-bit result, left adjusted
Bit
7
6
5
4
3
2
1
0
–
REFSEL[2:0]
–
–
BANDGAP
TEMPREF
REFCTRL
Read/Write
R
R/W
R/W
R/W
R
R
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0