ATMEGA48-20AUR Atmel, ATMEGA48-20AUR Datasheet - Page 26
![IC AVR MCU 4K 20MHZ 32TQFP](/photos/6/91/69154/313-32-tqfp_sml.jpg)
ATMEGA48-20AUR
Manufacturer Part Number
ATMEGA48-20AUR
Description
IC AVR MCU 4K 20MHZ 32TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheet
1.ATMEGA48-20AU.pdf
(35 pages)
Specifications of ATMEGA48-20AUR
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
4KB (2K x 16)
Program Memory Type
FLASH
Eeprom Size
256 x 8
Ram Size
512 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
*
Processor Series
ATMEGA4x
Core
AVR8
Data Bus Width
8 bit
Data Ram Size
512 B
Interface Type
SPI, UART, I2C
Maximum Clock Frequency
20 MHz
Number Of Programmable I/os
23
Operating Supply Voltage
2.7 V to 5.5 V
Maximum Operating Temperature
+ 105 C
Mounting Style
SMD/SMT
Operating Temperature Range
- 40 C to + 85 C
Processor To Be Evaluated
ATMEGA48A
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
8.3
8.3.1
8.3.2
2545SS–AVR–07/10
Errata ATmega168
Rev C
Rev B
3. Interrupts may be lost when writing the timer registers in the asynchronous timer
The revision letter in this section refers to the revision of the ATmega168 device.
•
1. Interrupts may be lost when writing the timer registers in the asynchronous timer
•
•
1. Part may hang in reset
Interrupts may be lost when writing the timer registers in the asynchronous timer
Part may hang in reset
Interrupts may be lost when writing the timer registers in the asynchronous timer
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.
The interrupt will be lost if a timer register that is synchronous timer clock is written when the
asynchronous Timer/Counter register (TCNTx) is 0x00.
Problem Fix/Workaround
Always check that the asynchronous Timer/Counter register neither have the value 0xFF nor
0x00 before writing to the asynchronous Timer Control Register (TCCRx), asynchronous
Timer Counter Register (TCNTx), or asynchronous Output Compare Register (OCRx).
The interrupt will be lost if a timer register that is synchronous timer clock is written when the
asynchronous Timer/Counter register (TCNTx) is 0x00.
Problem Fix/Workaround
Always check that the asynchronous Timer/Counter register neither have the value 0xFF nor
0x00 before writing to the asynchronous Timer Control Register (TCCRx), asynchronous
Timer Counter Register (TCNTx), or asynchronous Output Compare Register (OCRx).
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.
ATmega48/88/168
26