ATMEGA48-20AI Atmel, ATMEGA48-20AI Datasheet - Page 213

IC AVR MCU 4K 5V 20MHZ 32-TQFP

ATMEGA48-20AI

Manufacturer Part Number
ATMEGA48-20AI
Description
IC AVR MCU 4K 5V 20MHZ 32-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Datasheets

Specifications of ATMEGA48-20AI

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
32-TQFP, 32-VQFP
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
ATMEGA48-24AI
ATMEGA48-24AI

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
ATMEGA48-20AI
Manufacturer:
Atmel
Quantity:
10 000
2545S–AVR–07/10
Figure 21-7. SCL Synchronization Between Multiple Masters
Arbitration is carried out by all masters continuously monitoring the SDA line after outputting
data. If the value read from the SDA line does not match the value the Master had output, it has
lost the arbitration. Note that a Master can only lose arbitration when it outputs a high SDA value
while another Master outputs a low value. The losing Master should immediately go to Slave
mode, checking if it is being addressed by the winning Master. The SDA line should be left high,
but losing masters are allowed to generate a clock signal until the end of the current data or
address packet. Arbitration will continue until only one Master remains, and this may take many
bits. If several masters are trying to address the same Slave, arbitration will continue into the
data packet.
Figure 21-8. Arbitration Between Two Masters
SCL from
SCL from
Master A
Master B
SCL Bus
Synchronized
Line
SCL Line
SDA from
SDA from
Master A
Master B
SDA Line
START
TA
Counting Low Period
low
Masters Start
TB
low
Arbitration, SDA
ATmega48/88/168
Master A Loses
TA
Counting High Period
high
Masters Start
TB
high
A
SDA
213

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