Datasheet

AVR is set up with a long start-up time, the SCL line may be held low for a long time, blocking other data
transmissions.
Note: The 2-wire Serial Interface Data Register (TWDRn) does not reflect the last byte present on the
bus when waking up from these Sleep modes.
Table 23-5. Status Codes for Slave Transmitter Mode
Status Code
(TWSRb)
Prescaler
Bits are 0
Status of the 2-wire Serial
Bus and 2-wire Serial
Interface Hardware
Application SofTWARne Response Next Action Taken by TWI
Hardware
To/from
TWDRn
To TWCRn
STA STO TWINT TWEA
0xA8 Own SLA+R has been
received;
ACK has been returned
Load data
byte
X 0 1 0 Last data byte will be transmitted
and NOT ACK should be received
X 0 1 1 Data byte will be transmitted and
ACK should be received
0xB0 Arbitration lost in SLA+R/W as
Master;
own SLA+R has been
received;
ACK has been returned
Load data
byte
X 0 1 0 Last data byte will be transmitted
and NOT ACK should be received
X 0 1 1 Data byte will be transmitted and
ACK should be received
0xB8 Data byte in TWDRn has been
transmitted;
ACK has been received
Load data
byte
X 0 1 0 Last data byte will be transmitted
and NOT ACK should be received
X 0 1 1 Data byte will be transmitted and
ACK should be received
Atmel ATmega644A [DATASHEET]
Atmel-42716C-ATmega644A_Datasheet_Complete-10/2016
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