Rainbow Electronics ATmega64M1 - Manual (Page 237)

237
8209A–AVR–08/09
ATmega16M1/32M1/64M1
(ADC9 in ADCH). If the bit is one, the result is negative, and if this bit is zero, the result is posi-
tive.
Figure 22-14 shows the decoding of the differential input range.
Table 22-2 shows the resulting output codes if the differential input channel pair (ADCn - ADCm)
is selected with a reference voltage of V
REF
.
Figure 22-14. Differential Measurement Range
Table 22-2. Correlation Between Input Voltage and Output Codes
V
ADCn
Read code Corresponding decimal value
V
ADCm
+ V
REF
/GAIN 0x1FF 511
V
ADCm
+ 0.999 V
REF
/GAIN 0x1FF 511
V
ADCm
+ 0.998 V
REF
/GAIN 0x1FE 510
... ... ...
V
ADCm
+ 0.001 V
REF
/GAIN 0x001 1
V
ADCm
0x000 0
V
ADCm
- 0.001 V
REF
/GAIN 0x3FF -1
... ... ...
V
ADCm
- 0.999 V
REF
/GAIN 0x201 -511
V
ADCm
- V
REF
/GAIN 0x200 -512
0
Output Code
0x1FF
0x000
V
REF
Differential Input
Voltage (Volts)
0x3FF
0x200
- V
REF
/Gain /Gain