Datasheet

Note: The Two-wire serial interface Data Register (TWDRn) does not reflect the last byte present on the
bus when waking up from these Sleep modes.
Table 26-5. Status Codes for Slave Transmitter Mode
Status Code
(TWSRb)
Prescaler
Bits are 0
Status of the Two-Wire Serial
Bus and Two-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
0xC0 Data byte in TWDRn has been
transmitted;
NOT ACK has been received
No TWDRn
action
0 0 1 0 Switched to the not addressed
Slave mode;
no recognition of own SLA or
GCA
0 0 1 1 Switched to the not addressed
Slave mode;
own SLA will be recognized;
GCA will be recognized if
TWGCE = “1”
1 0 1 0 Switched to the not addressed
Slave mode;
no recognition of own SLA or
GCA;
a START condition will be
transmitted when the bus
becomes free
1 0 1 1 Switched to the not addressed
Slave mode;
own SLA will be recognized;
GCA will be recognized if
TWGCE = “1”; a START condition
will be transmitted when the bus
becomes free
ATmega48PA/88PA/168PA
Two-Wire Serial Interface (TWI)
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40002011A-page 292