ATMEGA644PV ATMEL [ATMEL Corporation], ATMEGA644PV Datasheet - Page 227

• Manufacturer Part Number: ATMEGA644PV
• Description: 8-bit Microcontroller with 16/32/64K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Table 19-5.
8011D–AVR–02/07
Status Code
(TWSR)
Prescaler Bits
are 0
0xA8
0xB0
0xB8
0xC0
0xC8
Status of the 2-wire Serial Bus and
2-wire Serial Interface Hardware
Own SLA+R has been received;
ACK has been returned
Arbitration lost in SLA+R/W as
Master; own SLA+R has been
received; ACK has been returned
Data byte in TWDR has been
transmitted; ACK has been
received
Data byte in TWDR has been
transmitted; NOT ACK has been
received
Last data byte in TWDR has been
transmitted (TWEA = “0”); ACK
has been received
Status Codes for Slave Transmitter Mode
To/from TWDR
Load data byte or
Load data byte
Load data byte or
Load data byte
Load data byte or
Load data byte
No TWDR action or
No TWDR action or
No TWDR action or
No TWDR action
No TWDR action or
No TWDR action or
No TWDR action or
No TWDR action
Application Software Response
STA
X
X
X
X
X
X
0
0
1
1
0
0
1
1
STO
0
0
0
0
0
0
0
0
0
0
0
0
0
0
To TWCR
TWINT
1
1
1
1
1
1
1
1
1
1
1
1
1
1
ATmega164P/324P/644P
TWEA
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Next Action Taken by TWI Hardware
Last data byte will be transmitted and NOT ACK should
be received
Data byte will be transmitted and ACK should be re-
ceived
Last data byte will be transmitted and NOT ACK should
be received
Data byte will be transmitted and ACK should be re-
ceived
Last data byte will be transmitted and NOT ACK should
be received
Data byte will be transmitted and ACK should be re-
ceived
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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