ATMEGA2561V ATMEL [ATMEL Corporation], ATMEGA2561V Datasheet - Page 293

• Manufacturer Part Number: ATMEGA2561V
• Description: 8-bit Microcontroller with 64K/128K/256K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

2549K–AVR–01/07
Table 127. Correlation Between Input Voltage and Output Codes
Example:
ADMUX = 0xFB (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.
ADCL will thus read 0x00, and ADCH will read 0x9C. Writing zero to ADLAR right
adjusts the result: ADCL = 0x70, ADCH = 0x02.
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
REF
REF
/ GAIN
/ GAIN
REF
REF
REF
REF
REF
/ GAIN
/ GAIN
/ GAIN
/ GAIN
/ GAIN
ATmega640/1280/1281/2560/2561
Read Code
0x1FF
0x1FF
0x1FE
...
0x001
0x000
0x3FF
...
0x201
0x200
Corresponding Decimal Value
-511
-512
511
511
510
-1
...
...
1
0
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