ATMEGA8-16AUR Atmel, ATMEGA8-16AUR Datasheet - Page 161
![IC MCU AVR 8K 16MHZ 5V 32TQFP](/photos/6/91/69154/313-32-tqfp_sml.jpg)
ATMEGA8-16AUR
Manufacturer Part Number
ATMEGA8-16AUR
Description
IC MCU AVR 8K 16MHZ 5V 32TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA8-16AUR
Core Processor
AVR
Core Size
8-Bit
Speed
16MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
23
Program Memory Size
8KB (4K x 16)
Program Memory Type
FLASH
Eeprom Size
512 x 8
Ram Size
1K x 8
Voltage - Supply (vcc/vdd)
4.5 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
32-TQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ATMEGA8-16AUR
Manufacturer:
AVX
Quantity:
4 000
- Current page: 161 of 302
- Download datasheet (6Mb)
Multi-master Bus
Systems,
Arbitration and
Synchronization
2486Z–AVR–02/11
The TWI protocol allows bus systems with several masters. Special concerns have been taken
in order to ensure that transmissions will proceed as normal, even if two or more masters initiate
a transmission at the same time. Two problems arise in multi-master systems:
•
•
The wired-ANDing of the bus lines is used to solve both these problems. The serial clocks from
all masters will be wired-ANDed, yielding a combined clock with a high period equal to the one
from the Master with the shortest high period. The low period of the combined clock is equal to
the low period of the Master with the longest low period. Note that all masters listen to the SCL
line, effectively starting to count their SCL high and low time-out periods when the combined
SCL line goes high or low, respectively.
Figure 74. 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.
An algorithm must be implemented allowing only one of the masters to complete the
transmission. All other masters should cease transmission when they discover that they
have lost the selection process. This selection process is called arbitration. When a
contending master discovers that it has lost the arbitration process, it should immediately
switch to Slave mode to check whether it is being addressed by the winning master. The fact
that multiple masters have started transmission at the same time should not be detectable to
the slaves, that is, the data being transferred on the bus must not be corrupted
Different masters may use different SCL frequencies. A scheme must be devised to
synchronize the serial clocks from all masters, in order to let the transmission proceed in a
lockstep fashion. This will facilitate the arbitration process
SCL from
SCL from
Master A
Master B
SCL Bus
Line
TA
Counting Low Period
low
Masters Start
TB
low
TA
Counting High Period
high
Masters Start
TB
high
ATmega8(L)
161
Related parts for ATMEGA8-16AUR
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATMEGA8-16AU](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ 5V 32TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16MU](/photos/12/32/123219/atmega8-16mu_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ 5V 32-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16PU](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ 5V 28DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16AC](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ COM 32-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16AI](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ IND 32-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16PC](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ COM 28-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16PI](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ IND 28-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16MC](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ COM 32-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16MUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 8KB FLASH 16MHZ 32QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16MI](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC AVR MCU 8K 16MHZ IND 32-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16AJ](/photos/6/91/69154/313-32-tqfp_tmb.jpg)
Part Number:
Description:
IC MCU AVR 8K 5V 16MHZ 32-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16MJ](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
IC MCU AVR 8K 5V 16MHZ 32-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA8-16PJ](/photos/7/21/72189/453-28-dip_tmb.jpg)
Part Number:
Description:
IC MCU AVR 8K 5V 16MHZ 28-DIP
Manufacturer:
Atmel
Datasheet: