145
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
Table 44.
Status Codes for Slave Transmitter Mode
Status
Code
(TWSR)
Status of the 2-wire
Serial Bus and 2-wire
Serial Hardware
Application Software Response
Next Action Taken by 2-wire
Serial Hardware
To/From TWDR
To TWCR
STA
STO
TWINT
TWEA
$A8
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
$B0
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
$B8
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
$C0
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 GC = “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 GC = “1”; a START condition
will be transmitted when the bus becomes
free
$C8
Last data byte in TWDR
has been transmitted
(TWAE = “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 GC = “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 GC = “1”; a START condition
will be transmitted when the bus becomes
free