Datasheet

203
ATmega48PA/88PA/168PA [DATASHEET]
9223F–AVR–04/14
Table 22-6. 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 HardwareTo/from TWDR
To TWCR
STA STO TWINT TWEA
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; GCA will be recognized
if TWGCE = “1”; a START condition will be
transmitted when the bus becomes free