ATMEGA168-15AZ Atmel, ATMEGA168-15AZ Datasheet - Page 231

• Manufacturer Part Number: ATMEGA168-15AZ
• Description: MCU AVR 16K FLASH 15MHZ 32-TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA168-15AZ

• Package / Case: 32-TQFP, 32-VQFP
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Speed: 16MHz
• Number Of I /o: 23
• Eeprom Size: 512 x 8
• Core Processor: AVR
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Program Memory Size: 16KB (16K x 8)
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Connectivity: I²C, SPI, UART/USART
• Core Size: 8-Bit
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 16MHz
• Interface Type: 2-Wire/USART/Serial
• Total Internal Ram Size: 1KB
• # I/os (max): 23
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 8-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 125C
• Operating Temperature Classification: Automotive
• Mounting: Surface Mount
• Pin Count: 32
• Package Type: TQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

19.8.5
7530I–AVR–02/10
Miscellaneous States
Figure 19-19. Formats and States in the Slave Transmitter Mode
There are two status codes that do not correspond to a defined TWI state, see
Status 0xF8 indicates that no relevant information is available because the TWINT Flag is not
set. This occurs between other states, and when the TWI is not involved in a serial transfer.
Status 0x00 indicates that a bus error has occurred during a 2-wire Serial Bus transfer. A bus
error occurs when a START or STOP condition occurs at an illegal position in the format frame.
Examples of such illegal positions are during the serial transfer of an address byte, a data byte,
or an acknowledge bit. When a bus error occurs, TWINT is set. To recover from a bus error, the
TWSTO Flag must set and TWINT must be cleared by writing a logic one to it. This causes the
TWI to enter the not addressed Slave mode and to clear the TWSTO Flag (no other bits in
TWCR are affected). The SDA and SCL lines are released, and no STOP condition is
transmitted.
Table 19-7.
Status
Code
(TWSR)
Prescaler
Bits
are 0
0xF8
0x00
Reception of the own
slave address and one or
more data bytes
Arbitration lost as master
and addressed as slave
Last data byte transmitted.
Switched to not addressed
slave (TWEA = '0')
Status of the 2-wire Se-
rial Bus and 2-wire Seri-
al Interface Hardware
No relevant state infor-
mation
TWINT = “0”
Bus error due to an ille-
gal START or STOP
condition
From master to slave
From slave to master
Miscellaneous States
available;
S
SLA
To/from
TWDR
No TWDR ac-
tion
No TWDR ac-
tion
Application Software Response
R
DATA
ATmega48/88/168 Automotive
$A8
$B0
A
A
n
ST
A
0
No TWCR action
A
ST
O
To TWCR
1
DATA
Any number of data bytes
and their associated acknowledge bits
This number (contained in TWSR) corresponds
to a defined state of the 2-Wire Serial Bus. The
prescaler bits are zero or masked to zero
TWI
NT
1
TW
EA
X
$B8
A
Next Action Taken by TWI Hardware
Wait or proceed current transfer
Only the internal hardware is affected, no
STOP condition is sent on the bus. In all
cases, the bus is released and TWSTO is
cleared.
DATA
$C0
$C8
A
A
Table
P or S
All 1's
19-7.
P or S
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