atmega32c1 ATMEL Corporation, atmega32c1 Datasheet - Page 239

• Manufacturer Part Number: atmega32c1
• Description: Atmega32m1 Automotive 8-bit Avr Microcontroller With 32k/64k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

7647A–AVR–02/08
Table 82 shows the resulting output codes if the differential input channel pair (ADCn - ADCm) is
selected with a reference voltage of V
Figure 18-14. Differential Measurement Range
Table 18-2.
Example 1:
V
V
V
...
V
V
V
...
V
V
V
ADCn
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
–
–
–
+ 0.999 V
+ 0.998 V
+ 0.001 V
- 0.001 V
- 0.999 V
- V
+ V
ADMUX = 0xED (ADC3 - ADC2, 10x gain, 2.56V reference, left adjusted result)
Voltage on ADC3 is 300 mV, voltage on ADC2 is 500 mV.
ADCR = 512 * 10 * (300 - 500) / 2560 = -400 = 0x270
- V
REF
REF
REF
/Gain
/GAIN
/GAIN
Correlation Between Input Voltage and Output Codes
REF
REF
REF
REF
REF
/GAIN
/GAIN
/GAIN
/GAIN
/GAIN
Read code
Output Code
0x3FF
0x1FF
0x1FF
0x1FE
0x3FF
0x001
0x000
0x201
0x200
REF
0x1FF
0x000
0x200
...
...
.
0
Corresponding decimal value
511
511
510
...
1
0
-1
...
-511
-512
ATmega32/64/M1/C1
V
REF
/Gain
Differential Input
Voltage (Volts)
239