ATMEGA1284P-AU Atmel, ATMEGA1284P-AU Datasheet - Page 57
![MCU AVR 128K ISP FLASH 44-TQFP](/photos/6/70/67042/313-44-tqfp_sml.jpg)
ATMEGA1284P-AU
Manufacturer Part Number
ATMEGA1284P-AU
Description
MCU AVR 128K ISP FLASH 44-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets
1.ATMEGA644PA-PU.pdf
(581 pages)
2.ATMEGA644PA-PU.pdf
(32 pages)
3.ATMEGA1284PR231-AU.pdf
(380 pages)
Specifications of ATMEGA1284P-AU
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
128KB (64K x 16)
Program Memory Type
FLASH
Eeprom Size
4K x 8
Ram Size
16K 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-TQFP, 44-VQFP
Processor Series
ATMEGA128x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
16 KB
Interface Type
2-Wire, SPI, USART
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
32
Number Of Timers
3
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, ATAVRRAVEN, ATAVRRZUSBSTICK
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 8 Channel
Package
44TQFP
Device Core
AVR
Family Name
ATmega
Maximum Speed
20 MHz
Operating Supply Voltage
2.5|3.3|5 V
Data Rom Size
4 KB
Height
1.05 mm
Length
10.1 mm
Supply Voltage (max)
5.5 V
Supply Voltage (min)
1.8 V
Width
10.1 mm
Controller Family/series
AVR MEGA
No. Of I/o's
32
Eeprom Memory Size
4KB
Ram Memory Size
16KB
Cpu Speed
20MHz
Rohs Compliant
Yes
For Use With
ATSTK600-TQFP44 - STK600 SOCKET/ADAPTER 44-TQFPATSTK600 - DEV KIT FOR AVR/AVR32
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA1284P-AU
Manufacturer:
ATMEL
Quantity:
1 000
Company:
Part Number:
ATMEGA1284P-AU
Manufacturer:
ATMEL
Quantity:
748
Part Number:
ATMEGA1284P-AU
Manufacturer:
MICROCHIP/微芯
Quantity:
20 000
9.4.2
8059D–AVR–11/09
WDTCSR – Watchdog Timer Control Register
• Bit 7 - WDIF: Watchdog Interrupt Flag
This bit is set when a time-out occurs in the Watchdog Timer and the Watchdog Timer is config-
ured 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 Interrupt
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 use-
ful 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 Sys-
tem Reset will be applied.
Table 9-1.
• 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 con-
ditions causing failure, and a safe start-up after the failure.
Bit
(0x60)
Read/Write
Initial Value
WDTON
0
0
0
0
1
Watchdog Timer Configuration
WDIF
R/W
WDE
7
0
0
0
1
1
x
WDIE
R/W
6
0
WDIE
0
1
0
1
x
WDP3
R/W
5
0
Mode
Stopped
Interrupt Mode
System Reset Mode
Interrupt and System Reset
Mode
System Reset Mode
WDCE
R/W
4
0
WDE
R/W
X
3
WDP2
R/W
2
0
ATmega1284P
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
57