226
7530J–AVR–03/12
Atmel ATmega48/88/168 Automotive
Table 19-5.
Status Codes for Slave Receiver Mode
Status
Code
(TWSR)
Prescaler
Bits
are 0
Status of the 2-wire Seri-
al Bus and 2-wire Serial
Interface Hardware
Application Software Response
Next Action Taken by TWI Hardware
To/from
TWDR
To TWCR
ST
A
ST
O
TWI
NT
TW
EA
0x60
Own SLA+W has been
received;
ACK has been returned
No TWDR ac-
tion or
No TWDR ac-
tion
X
0
1
0
1
Data byte will be received and NOT ACK
will be
returned
Data byte will be received and ACK will
be returned
0x68
Arbitration
lost
in
SLA+R/W
as
Master;
own SLA+W has been
received; ACK has been
returned
No TWDR ac-
tion or
No TWDR ac-
tion
X
0
1
0
1
Data byte will be received and NOT ACK
will be
returned
Data byte will be received and ACK will
be returned
0x70
General call address has
been
received; ACK has been
returned
No TWDR ac-
tion or
No TWDR ac-
tion
X
0
1
0
1
Data byte will be received and NOT ACK
will be
returned
Data byte will be received and ACK will
be returned
0x78
Arbitration
lost
in
SLA+R/W
as
Master;
General call address has
been received; ACK has
been
returned
No TWDR ac-
tion or
No TWDR ac-
tion
X
0
1
0
1
Data byte will be received and NOT ACK
will be
returned
Data byte will be received and ACK will
be returned
0x80
Previously
addressed
with own SLA+W; data
has been received; ACK
has been returned
Read
data
byte or
Read
data
byte
X
0
1
0
1
Data byte will be received and NOT ACK
will be
returned
Data byte will be received and ACK will
be returned
0x88
Previously
addressed
with own SLA+W; data
has been received; NOT
ACK has been returned
Read
data
byte or
Read
data
byte or
Read
data
byte or
Read
data
byte
0
1
0
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