ATMEGA8_14 Datasheet, PDF (179/331 Pages) ATMEL Corporation – High-performance, Low-power Atmel

ATmega8(L)
Table 68. Status Codes for Slave Receiver Mode
Status Code
(TWSR)
Prescaler Bits
are 0
0x60
0x68
0x70
0x78
0x80
0x88
Status of the Two-wire Serial Bus
and Two-wire Serial Interface
Hardware
Own SLA+W has been received;
ACK has been returned
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
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
Application Software Response
To/from TWDR
STA
To TWCR
STO TWINT
No TWDR action or
X
0
1
No TWDR action
X
0
1
No TWDR action or
X
0
1
No TWDR action
X
0
1
No TWDR action or
X
0
1
No TWDR action
X
0
1
No TWDR action or
X
0
1
No TWDR action
X
0
1
Read data byte or
X
0
1
Read data byte
X
0
1
Read data byte or
0
0
1
Read data byte or
0
0
1
Read data byte or
1
0
1
Read data byte
1
0
1
0x90
0x98
Previously addressed with
Read data byte or
X
0
1
general call; data has been re-
ceived; ACK has been returned
Read data byte
X
0
1
Previously addressed with
Read data byte or
0
0
1
general call; data has been
received; NOT ACK has been
Read data byte or
0
0
1
returned
Read data byte or
1
0
1
Read data byte
1
0
1
0xA0
A STOP condition or repeated
START condition has been
received while still addressed as
Slave
No action
0
0
1
0
0
1
1
0
1
1
0
1
TWEA
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Next Action Taken by TWI Hardware
Data byte will be received and NOT ACK will be re-
turned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be re-
turned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be re-
turned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be re-
turned
Data byte will be received and ACK will be returned
Data byte will be received and NOT ACK will be re-
turned
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 re-
turned
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
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