ATMEGA168-20AUR Atmel, ATMEGA168-20AUR Datasheet - Page 23
![MCU AVR 16KB FLASH 20MHZ 32TQFP](/photos/6/91/69154/313-32-tqfp_sml.jpg)
ATMEGA168-20AUR
Manufacturer Part Number
ATMEGA168-20AUR
Description
MCU AVR 16KB FLASH 20MHZ 32TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA168-20AUR
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
16KB (8K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K 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
Package
32TQFP
Device Core
AVR
Family Name
ATmega
Maximum Speed
20 MHz
Operating Supply Voltage
3.3|5 V
Data Bus Width
8 Bit
Number Of Programmable I/os
23
Interface Type
SPI/TWI/USART
On-chip Adc
8-chx10-bit
Number Of Timers
3
For Use With
ATSTK600-TQFP32 - STK600 SOCKET/ADAPTER 32-TQFPATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVR
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
8.1.4
2545SS–AVR–07/10
Rev A
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1. Part may hang in reset
2. Wrong values read after Erase Only operation
Part may hang in reset
Wrong values read after Erase Only operation
Watchdog Timer Interrupt disabled
Start-up time with Crystal Oscillator is higher than expected
High Power Consumption in Power-down with External Clock
Asynchronous Oscillator does not stop in Power-down
Interrupts may be lost when writing the timer registers in the asynchronous timer
Some parts may get stuck in a reset state when a reset signal is applied when the internal
reset state-machine is in a specific state. The internal reset state-machine is in this state for
approximately 10 ns immediately before the part wakes up after a reset, and in a 10 ns win-
dow when altering the system clock prescaler. The problem is most often seen during In-
System Programming of the device. There are theoretical possibilities of this happening also
in run-mode. The following three cases can trigger the device to get stuck in a reset-state:
- Two succeeding resets are applied where the second reset occurs in the 10 ns window
before the device is out of the reset-state caused by the first reset.
- A reset is applied in a 10 ns window while the system clock prescaler value is updated by
software.
- Leaving SPI-programming mode generates an internal reset signal that can trigger this
case.
The two first cases can occur during normal operating mode, while the last case occurs only
during programming of the device.
Problem Fix/Workaround
The first case can be avoided during run-mode by ensuring that only one reset source is
active. If an external reset push button is used, the reset start-up time should be selected
such that the reset line is fully debounced during the start-up time.
The second case can be avoided by not using the system clock prescaler.
The third case occurs during In-System programming only. It is most frequently seen when
using the internal RC at maximum frequency.
If the device gets stuck in the reset-state, turn power off, then on again to get the device out
of this state.
At supply voltages below 2.7V, an EEPROM location that is erased by the Erase Only oper-
ation may read as programmed (0x00).
Problem Fix/Workaround
If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write opera-
tion with 0xFF as data in order to erase a location. In any case, the Write Only operation can
be used as intended. Thus no special considerations are needed as long as the erased loca-
tion is not read before it is programmed.
ATmega48/88/168
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