ATMEGA64-16AI Atmel, ATMEGA64-16AI Datasheet - Page 57

• Manufacturer Part Number: ATMEGA64-16AI
• Description: IC AVR MCU 64K 16MHZ IND 64-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• 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): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

WDTCR – Watchdog
Timer Control Register
2490Q–AVR–06/10
Table 21. WDT Configuration as a Function of the Fuse Settings of M103C and WDTON
Figure 28. Watchdog Timer
• Bits 7..5 – Res: Reserved Bits
These bits are reserved bits in the ATmega64 and will always read as zero.
• Bit 4 – WDCE: Watchdog Change Enable
This bit must be set when the WDE bit is written to logic zero. Otherwise, the Watchdog will not
be disabled. Once written to one, hardware will clear this bit after four clock cycles. Refer to the
description of the WDE bit for a Watchdog disable procedure. In Safety Level 1 and 2, this bit
must also be set when changing the prescaler bits.
Configuration of the Watchdog Timer” on page 60.
• Bit 3 – WDE: Watchdog Enable
When the WDE is written to logic one, the Watchdog Timer is enabled, and if the WDE is written
to logic zero, the Watchdog Timer function is disabled. WDE can only be cleared if the WDCE bit
Bit
0x21 (0x41)
Read/Write
Initial Value
M103C
Unprogrammed
Unprogrammed
Programmed
Programmed
R
7
–
0
WDTON
Unprogrammed
Programmed
Unprogrammed
Programmed
OSCILLATOR
WATCHDOG
R
6
–
0
R
5
–
0
Safety
Level
1
2
0
2
WDCE
R/W
4
0
WDT
Initial
State
Disabled
Enabled
Disabled
Enabled
WDE
R/W
3
0
See “Timed Sequences for Changing the
WDP2
R/W
Timed
enabled
Timed
sequence
enabled
How to
Disable the
WDT
sequence
Always
Always
2
0
WDP1
R/W
1
0
ATmega64(L)
WDP0
R/W
How to
Change
Time-out
Timed
sequence
Timed
sequence
No restriction
Timed
sequence
0
0
WDTCR
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