ATMEGA48-20AI Atmel, ATMEGA48-20AI Datasheet - Page 54

• Manufacturer Part Number: ATMEGA48-20AI
• Description: IC AVR MCU 4K 5V 20MHZ 32-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA48-20AI

• 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: 23
• Program Memory Size: 4KB (2K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: ATMEGA48-24AI; ATMEGA48-24AI

54
ATmega48/88/168
• 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.
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
54.
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
2545S–AVR–07/10