ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 255

• Manufacturer Part Number: ATMEGA644A-PU
• Description: IC MCU AVR 64K FLASH 40PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644A-PU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• 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: 40-DIP (0.600", 15.24mm)
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: JTAG, TWI, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8272A–AVR–01/10
Figure 22-14. Differential Measurement Range
Table 22-2.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
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
+ 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
0x1FF
0x1FF
0x1FE
...
0x001
0x000
0x3FF
...
0x201
0x200
Output Code
0x3FF
0x1FF
0x000
0
0x200
Corresponding Decimal Value
511
511
510
...
1
0
-1
...
-511
-512
V
REF
/GAIN Differential Input
Voltage (Volts)
255