ATMEGA8515-16AI Atmel, ATMEGA8515-16AI Datasheet - Page 51

• Manufacturer Part Number: ATMEGA8515-16AI
• Description: IC AVR MCU 8K 16MHZ IND 44-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8515-16AI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 35
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -

Watchdog Timer Control
Register – WDTCR
2512K–AVR–01/10
Table 20. WDT Configuration as a Function of the Fuse Settings of S8515C and
WDTON.
Figure 28. Watchdog Timer
• Bits 7..5 – Res: Reserved Bits
These bits are reserved bits in the ATmega8515 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 Levels 1 and 2, this bit must also be set when changing the prescaler bits. See
“Timed Sequences for Changing the Configuration of the Watchdog Timer” on page 53.
• 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 has logic level one. To disable an enabled Watchdog Timer, the follow-
ing procedure must be followed:
Bit
Read/Write
Initial Value
S8515C
Unprogrammed
Unprogrammed
Programmed
Programmed
R
7
–
0
WDTON
Unprogrammed
Programmed
Unprogrammed
Programmed
R
OSCILLATOR
6
–
0
WATCHDOG
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
How to Disable
the WDT
Timed sequence
Always enabled
Timed sequence
Always enabled
WDP2
R/W
2
0
ATmega8515(L)
WDP1
R/W
1
0
WDP0
R/W
How to
Change Time-
out
Timed
sequence
Timed
sequence
No restriction
Timed
sequence
0
0
WDTCR
51