
222
AT90CAN128
4250E–CAN–12/04
Table 92.
Status Codes for Slave Receiver Mode
Status Code
(TWSR)
Prescaler Bits
are 0
0x60
Status of the Two-wire Serial Bus
and Two-wire Serial Interface
Hardware
Own SLA+W has been received;
ACK has been returned
Application Software Response
Next Action Taken by TWI Hardware
Data byte will be received and NOT ACK will be
returned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be
returned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be
returned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be
returned
Data byte will be received and ACK will be returned
To/from TWDR
To TWCR
STA
STO
TWINT
TWEA
No TWDR action or
No TWDR action
No TWDR action or
X
X
X
0
0
0
1
1
1
0
1
0
0x68
Arbitration lost in SLA+R/W as
master; own SLA+W has been
received; ACK has been returned
General call address has been
received; ACK has been returned
No TWDR action
No TWDR action or
X
X
0
0
1
1
1
0
0x70
No TWDR action
No TWDR action or
X
X
0
0
1
1
1
0
0x78
Arbitration lost in SLA+R/W as
master; General call address has
been received; ACK has been
returned
Previously addressed with own
SLA+W; data has been received;
ACK has been returned
Previously addressed with own
SLA+W; data has been received;
NOT ACK has been returned
No TWDR action
X
0
1
1
0x80
Read data byte or
Read data byte
Read data byte or
X
X
0
0
0
0
1
1
1
0
1
0
Data byte will be received and NOT ACK will be
returned
Data byte will be received and ACK will be returned
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
Data byte will be received and NOT ACK will be
returned
Data byte will be received and ACK will be returned
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
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
0x88
Read data byte or
Read data byte or
Read data byte
0
1
1
0
0
0
1
1
1
1
0
1
0x90
Previously addressed with
general call; data has been re-
ceived; ACK has been returned
Previously addressed with
general call; data has been
received; NOT ACK has been
returned
Read data byte or
Read data byte
Read data byte or
X
X
0
0
0
0
1
1
1
0
1
0
0x98
Read data byte or
Read data byte or
Read data byte
0
1
1
0
0
0
1
1
1
1
0
1
0xA0
A STOP condition or repeated
START condition has been
received while still addressed as
slave
Read data byte or
Read data byte or
Read data byte or
Read data byte
0
0
1
1
0
0
0
0
1
1
1
1
0
1
0
1