atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 324

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

324
ATmega32U4
where V
Table 25-3 on page 326
0x3FF represents the selected reference voltage minus one LSB.
If differential channels are used, the result is:
where V
GAIN the selected gain factor and V
in two’s complement form, from 0x200 (-512d) through 0x1FF (+511d). Note that if the user
wants to perform a quick polarity check of the result, it is sufficient to read the MSB of the result
(ADC9 in ADCH). If the bit is one, the result is negative, and if this bit is zero, the result is posi-
tive.
Table 82 shows the resulting output codes if the differential input channel pair (ADCn - ADCm) is
selected with a reference voltage of V
Figure 25-15. Differential Measurement Range
Figure 25-15
IN
POS
- V
is the voltage on the selected input pin and V
REF
is the voltage on the positive input pin, V
shows the decoding of the differential input range.
and
Table 25-4 on page
ADC
REF
Output Code
REF
0x3FF
ADC
=
the selected voltage reference. The result is presented
.
0x1FF
0x000
0x200
(
----------------------------------------------------------------------- -
V
=
POS
0
V
--------------------------
IN
V
–
⋅
REF
326). 0x000 represents analog ground, and
V
1023
NEG
NEG
V
REF
REF
) GAIN 512
⋅
the voltage on the negative input pin,
the selected voltage reference (see
⋅
V
REF
7766A–AVR–03/08
Differential Input
Voltage (Volts)