ATMEGA64M1-15MZ Atmel, ATMEGA64M1-15MZ Datasheet - Page 55

• Manufacturer Part Number: ATMEGA64M1-15MZ
• Description: MCU AVR 64KB FLASH 3PSC 32-VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64M1-15MZ

• Package / Case: 32-VQFN
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Eeprom Size: 2K x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 4K x 8
• Program Memory Size: 64KB (64K x 8)
• Data Converters: A/D 11x10b; D/A 1x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Connectivity: CAN, LIN, SPI, UART/USART
• Core Size: 8-Bit
• Processor Series: ATMEGA64x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, ATADAPCAN01
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of I /o: -
• Lead Free Status / Rohs Status: Details

7.4.1
7647G–AVR–09/11
Watchdog Timer Control Register - WDTCSR
• Bit 7 - WDIF: Watchdog Interrupt Flag
This bit is set when a time-out occurs in the Watchdog Timer and the Watchdog Timer is con-
figured for interrupt. WDIF is cleared by hardware when executing the corresponding interrupt
handling vector. Alternatively, WDIF is cleared by writing a logic one to the flag. When the I-bit
in SREG and WDIE are set, the Watchdog Time-out Interrupt is executed.
• Bit 6 - WDIE: Watchdog Interrupt Enable
When this bit is written to one and the I-bit in the Status Register is set, the Watchdog Interrupt
is enabled. If WDE is cleared in combination with this setting, the Watchdog Timer is in Inter-
rupt Mode, and the corresponding interrupt is executed if time-out in the Watchdog Timer
occurs.
If WDE is set, the Watchdog Timer is in Interrupt and System Reset Mode. The first time-out in
the Watchdog Timer will set WDIF. Executing the corresponding interrupt vector will clear
WDIE and WDIF automatically by hardware (the Watchdog goes to System Reset Mode). This
is useful for keeping the Watchdog Timer security while using the interrupt. To stay in Interrupt
and System Reset Mode, WDIE must be set after each interrupt. This should however not be
done within the interrupt service routine itself, as this might compromise the safety-function of
the Watchdog System Reset mode. If the interrupt is not executed before the next time-out, a
System Reset will be applied.
Table 7-5.
Note:
• Bit 4 - WDCE: Watchdog Change Enable
This bit is used in timed sequences for changing WDE and prescaler bits. To clear the WDE
bit, and/or change the prescaler bits, WDCE must be set.
Once written to one, hardware will clear WDCE after four clock cycles.
• Bit 3 - WDE: Watchdog System Reset Enable
WDE is overridden by WDRF in MCUSR. This means that WDE is always set when WDRF is
set. To clear WDE, WDRF must be cleared first. This feature ensures multiple resets during
conditions causing failure, and a safe start-up after the failure.
• 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 7-6 on page
Bit
Read/Write
Initial Value
WDTON
0
0
0
0
1
1. For the WDTON Fuse “1” means unprogrammed while “0” means programmed.
(1)
Watchdog Timer Configuration
WDIF
R/W
7
0
WDE
56.
0
0
1
1
x
WDIE
R/W
6
0
WDIE
0
1
0
1
x
WDP3
R/W
5
0
Atmel ATmega16/32/64/M1/C1
Mode
Stopped
Interrupt Mode
System Reset Mode
Interrupt and System Reset
Mode
System Reset Mode
WDCE
R/W
4
0
WDE
R/W
3
X
WDP2
R/W
2
0
Action on Time-out
None
Interrupt
Reset
Interrupt, then go to
System Reset Mode
Reset
WDP1
R/W
1
0
WDP0
R/W
0
0
WDTCSR
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