Datasheet

Note: The 2-wire Serial Interface Data Register (TWDR) does not reflect the last byte present on the bus
when waking up from these Sleep modes.
Table 25-6. Status Codes for Slave Transmitter Mode
Status
Code
(TWSR)
Prescaler
Bits are 0
Status of the 2-wire Serial
Bus and 2-wire Serial
Interface Hardware
Application Software Response Next Action Taken by TWI Hardware
To/from TWDR To TWCR
STA STO TWI
NT
TWE
A
0xA8 Own SLA+R has been
received;
ACK has been returned
Load data byte or
Load data byte
X
X
0
0
1
1
0
1
Last data byte will be transmitted and NOT ACK
should be received
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 or
Load data byte
X
X
0
0
1
1
0
1
Last data byte will be transmitted and NOT ACK
should be received
Data byte will be transmitted and ACK should be
received
0xB8 Data byte in TWDR has
been
transmitted; ACK has been
received
Load data byte or
Load data byte
X
X
0
0
1
1
0
1
Last data byte will be transmitted and NOT ACK
should be received
Data byte will be transmitted and ACK should be
received
0xC0 Data byte in TWDR has
been
transmitted; NOT ACK has
been
received
No TWDR action
or
No TWDR action
or
No TWDR action
or
No TWDR action
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
1
Switched to the not addressed Slave mode;
no recognition of own SLA or GCA
Switched to the not addressed Slave mode;
own SLA will be recognized;
GCA will be recognized if TWGCE = “1”
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
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
0xC8
Last data byte in TWDR has
been transmitted (TWEA =
“0”); ACK has been received
No TWDR action
or
No TWDR action
or
No TWDR action
or
No TWDR action
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
1
Switched to the not addressed Slave mode;
no recognition of own SLA or GCA
Switched to the not addressed Slave mode;
own SLA will be recognized;
GCA will be recognized if TWGCE = “1”
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
Switched to the not addressed Slave mode;
own SLA will be recognized;
AVR 8-Bit Microcontroller
TWI - Two-wire Serial Interface
© 2017 Microchip Technology Inc.
Datasheet Complete
40001974A-page 237