ATMEGA48A-PU Atmel, ATMEGA48A-PU Datasheet - Page 35

IC MCU AVR 4K FLASH 28PDIP

ATMEGA48A-PU

Manufacturer Part Number
ATMEGA48A-PU
Description
IC MCU AVR 4K FLASH 28PDIP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA48A-PU

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)
1.8 V ~ 5.5 V
Data Converters
A/D 6x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
28-DIP (0.300", 7.62mm)
Controller Family/series
Atmega
No. Of I/o's
23
Eeprom Memory Size
256Byte
Ram Memory Size
512Byte
Cpu Speed
20MHz
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
8.9
8.10
8271C–AVR–08/10
Clock Output Buffer
Timer/Counter Oscillator
Figure 8-4.
When this clock source is selected, start-up times are determined by the SUT Fuses as shown in
Table
Table 8-16.
When applying an external clock, it is required to avoid sudden changes in the applied clock fre-
quency to ensure stable operation of the MCU. A variation in frequency of more than 2% from
one clock cycle to the next can lead to unpredictable behavior. If changes of more than 2% is
required, ensure that the MCU is kept in Reset during the changes.
Note that the System Clock Prescaler can be used to implement run-time changes of the internal
clock frequency while still ensuring stable operation. Refer to
36
The device can output the system clock on the CLKO pin. To enable the output, the CKOUT
Fuse has to be programmed. This mode is suitable when the chip clock is used to drive other cir-
cuits on the system. The clock also will be output during reset, and the normal operation of I/O
pin will be overridden when the fuse is programmed. Any clock source, including the internal RC
Oscillator, can be selected when the clock is output on CLKO. If the System Clock Prescaler is
used, it is the divided system clock that is output.
ATmega48A/48PA/88A/88PA/168A/168PA/328/328P uses the same crystal oscillator for Low-
frequency Oscillator and Timer/Counter Oscillator. See
page 32
ATmega48A/48PA/88A/88PA/168A/168PA/328/328P share the Timer/Counter Oscillator Pins
(TOSC1 and TOSC2) with XTAL1 and XTAL2. When using the Timer/Counter Oscillator, the
system clock needs to be four times the oscillator frequency. Due to this and the pin sharing, the
ATmega48A/48PA/88A/88PA/168A/168PA/328/328
BOD enabled
Fast rising power
Slowly rising power
for details.
Power Conditions
8-16.
for details on the oscillator and crystal requirements.
External Clock Drive Configuration
Start-up Times for the External Clock Selection
EXTERNAL
SIGNAL
CLOCK
Start-up Time from Power-
down and Power-save
PB7
Reserved
6 CK
6 CK
6 CK
XTAL2
XTAL1
GND
”Low Frequency Crystal Oscillator” on
Additional Delay from
”System Clock Prescaler” on page
Reset (V
14CK + 4.1 ms
14CK + 65 ms
14CK
CC
= 5.0V)
SUT1...0
00
01
10
11
35

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