ATMEGA2561V-8MI Atmel, ATMEGA2561V-8MI Datasheet - Page 254

• Manufacturer Part Number: ATMEGA2561V-8MI
• Description: IC AVR MCU 256K 8MHZ 64-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA2561V-8MI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• Program Memory Size: 256KB (128K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 8K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Table 23-2.
2549M–AVR–09/10
Status Code
(TWSR)
Prescaler Bits
are 0
0x08
0x10
0x18
0x20
0x28
0x30
0x38
Status of the 2-wire Serial Bus
and 2-wire Serial Interface Hard-
ware
A START condition has been
transmitted
A repeated START condition
has been transmitted
SLA+W has been transmitted;
ACK has been received
SLA+W has been transmitted;
NOT ACK has been received
Data byte has been transmitted;
ACK has been received
Data byte has been transmitted;
NOT ACK has been received
Arbitration lost in SLA+W or data
bytes
Status codes for Master Transmitter Mode
This scheme is repeated until the last byte has been sent and the transfer is ended by generat-
ing a STOP condition or a repeated START condition. A STOP condition is generated by writing
the following value to TWCR:
A REPEATED START condition is generated by writing the following value to TWCR:
After a repeated START condition (state 0x10) the 2-wire Serial Interface can access the same
Slave again, or a new Slave without transmitting a STOP condition. Repeated START enables
the Master to switch between Slaves, Master Transmitter mode and Master Receiver mode with-
out losing control of the bus.
TWCR
value
TWCR
value
To/from TWDR
Load SLA+W
Load SLA+W or
Load SLA+R
Load data byte or
No TWDR action or
No TWDR action or
No TWDR action
Load data byte or
No TWDR action or
No TWDR action or
No TWDR action
Load data byte or
No TWDR action or
No TWDR action or
No TWDR action
Load data byte or
No TWDR action or
No TWDR action or
No TWDR action
No TWDR action or
No TWDR action
TWINT
TWINT
1
1
Application Software Response
TWEA
TWEA
X
X
STA
0
0
0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
ATmega640/1280/1281/2560/2561
TWSTA
TWSTA
STO
0
0
0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
0
1
To TWCR
TWINT
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
TWSTO
TWSTO
1
0
TWEA
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Next Action Taken by TWI Hardware
SLA+W will be transmitted;
ACK or NOT ACK will be received
SLA+W will be transmitted;
ACK or NOT ACK will be received
SLA+R will be transmitted;
Logic will switch to Master Receiver mode
Data byte will be transmitted and ACK or NOT ACK will
be received
Repeated START will be transmitted
STOP condition will be transmitted and
TWSTO Flag will be reset
STOP condition followed by a START condition will be
transmitted and TWSTO Flag will be reset
Data byte will be transmitted and ACK or NOT ACK will
be received
Repeated START will be transmitted
STOP condition will be transmitted and
TWSTO Flag will be reset
STOP condition followed by a START condition will be
transmitted and TWSTO Flag will be reset
Data byte will be transmitted and ACK or NOT ACK will
be received
Repeated START will be transmitted
STOP condition will be transmitted and
TWSTO Flag will be reset
STOP condition followed by a START condition will be
transmitted and TWSTO Flag will be reset
Data byte will be transmitted and ACK or NOT ACK will
be received
Repeated START will be transmitted
STOP condition will be transmitted and
TWSTO Flag will be reset
STOP condition followed by a START condition will be
transmitted and TWSTO Flag will be reset
2-wire Serial Bus will be released and not addressed
Slave mode entered
A START condition will be transmitted when the bus be-
comes free
TWWC
TWWC
X
X
TWEN
TWEN
1
1
–
0
–
0
TWIE
TWIE
X
X
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