MEGA128CAN Datasheet, PDF (225/413 Pages) ATMEL Corporation – Microcontroller WITH 128K BYTES OF ISP FLASH AND CAN CONTROLLER

AT90CAN128
until the TWINT flag is cleared (by writing it to one). Further data transmission will be
carried out as normal, with the AVR clocks running as normal. Observe that if the AVR is
set up with a long start-up time, the SCL line may be held low for a long time, blocking
other data transmissions.
Note that the Two-wire Serial Interface Data Register – TWDR does not reflect the last
byte present on the bus when waking up from these sleep modes.
Table 93. Status Codes for Slave Transmitter Mode
Status Code
(TWSR)
Prescaler Bits
are 0
0xA8
Status of the Two-wire Serial Bus
and Two-wire Serial Interface
Hardware
Own SLA+R has been received;
ACK has been returned
Application Software Response
To/from TWDR
To TWCR
STA
STO
Load data byte or X
0
Load data byte
X
0
0xB0
Arbitration lost in SLA+R/W as Load data byte or X
0
master; own SLA+R has been
received; ACK has been returned Load data byte
X
0
0xB8
Data byte in TWDR has been
Load data byte or X
0
transmitted; ACK has been
received
Load data byte
X
0
0xC0
Data byte in TWDR has been
No TWDR action or 0
0
transmitted; NOT ACK has been
received
No TWDR action or 0
0
No TWDR action or 1
0
No TWDR action
1
0
0xC8
Last data byte in TWDR has been No TWDR action or 0
0
transmitted (TWEA = “0”); ACK
has been received
No TWDR action or 0
0
No TWDR action or 1
0
No TWDR action
1
0
TWINT
1
1
1
1
1
1
1
1
1
1
1
1
1
1
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
4250E–CAN–12/04
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