ATMEGA644PA-MU Atmel, ATMEGA644PA-MU Datasheet - Page 61

• Manufacturer Part Number: ATMEGA644PA-MU
• Description: IC MCU 8BIT 64KB FLASH 44VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644PA-MU

• 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: 44-VQFN Exposed Pad
• Processor Series: ATMEGA64x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, TWI, UART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 32
• Operating Supply Voltage: 1.8 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8272A–AVR–01/10
• Bit 5, 2:0 - WDP3:0: Watchdog Timer Prescaler 3, 2, 1 and 0
The WDP3:0 bits determine the Watchdog Timer prescaling when the Watchdog Timer is run-
ning. The different prescaling values and their corresponding time-out periods are shown in
Table 10-2 on page
.
Table 10-2.
164A/164PA/324A/324PA/644A/644PA/1284/1284P
WDP3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
WDP2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Watchdog Timer Prescale Select
61.
WDP1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
WDP0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Number of WDT Oscillator
1024K (1048576) cycles
128K (131072) cycles
256K (262144) cycles
512K (524288) cycles
16K (16384) cycles
32K (32768) cycles
64K (65536) cycles
2K (2048) cycles
4K (4096) cycles
8K (8192) cycles
Cycles
Reserved
Typical Time-out at
V
CC
0.125 s
16 ms
32 ms
64 ms
0.25 s
0.5 s
1.0 s
2.0 s
4.0 s
8.0 s
= 5.0V
61