ATMEGA645A-MUR Atmel, ATMEGA645A-MUR Datasheet - Page 226

• Manufacturer Part Number: ATMEGA645A-MUR
• Description: IC MCU AVR 64K FLASH 64QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA645A-MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/645
Table 22-2.
ADMUX = 0xFB (ADC3 - ADC2, 1.1V reference, left adjusted result)
Voltage on ADC3 is 300 mV, voltage on ADC2 is 500 mV.
ADCR = 512 * (300 - 500) / 1100 = -93 = 0x3A3.
ADCL will thus read 0xC0, and ADCH will read 0xD8. Writing zero to ADLAR right adjusts the
result: ADCL = 0xA3, ADCH = 0x03.
V
V
V
...
V
V
V
...
V
V
V
ADCn
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
ADCm
+
+
+
-
-
- V
+ V
1
511
511
510
1
/
/
512
REF
512
REF
/
/
/
512
512
512
V
V
REF
V
Correlation Between Input Voltage and Output Codes
REF
V
V
REF
REF
REF
Read Code
0x1FF
0x1FF
0x1FE
...
0x001
0x000
0x3FF
...
0x201
0x200
Corresponding Decimal Value
-511
-512
511
511
510
-1
...
...
1
0
8285B–AVR–03/11