ATMEGA128RFA1_11 Datasheet, PDF (391/560 Pages) ATMEL Corporation – 8-bit Microcontroller with Low Power 2.4GHz Transceiver for ZigBee and IEEE 802.15.4

ATmega128RFA1
Table 25-3. Status codes for Master Transmitter Mode
Status Code
(TWSR)
Prescaler
Bits are 0
0x08
0x10
Status of the 2-wire
Serial Bus and 2-wire
Serial Interface
Hardware
A START condition has
been transmitted
A repeated START
condition has been
transmitted
Application Software Response
To TWCR
To/from TWDR
Load SLA+W
STA STO TWINT
0
0
1
Load SLA+W or
0
0
1
Load SLA+R
0
0
1
0x18
SLA+W has been
Load data byte o
0
0
1
transmitted; ACK has
been received
No TWDR action or
1
0
1
TWEA
X
X
X
X
X
Next Action Taken by TWI
Hardware
SLA+W will be transmitted; ACK or
NOT ACK will be received
SLA+W will be transmitted; ACK or
NOT ACK will be received
SLA+R will be transmitted; Logic will
switch to Master Receiver mode
Data byte will be transmitted and
ACK or NOT ACK will be received
Repeated START will be transmitted
0x20
No TWDR action or
0
1
1
No TWDR action
1
1
1
SLA+W has been
Load data byte or
0
0
1
transmitted; NOT ACK
has been received
No TWDR action or
1
0
1
X
STOP condition will be transmitted
and TWSTO Flag will be reset
X
STOP condition followed by a START
condition will be transmitted and
TWSTO Flag will be reset
X
Data byte will be transmitted and
ACK or NOT ACK will be received
X
Repeated START will be transmitted
0x28
No TWDR action or
0
1
1
No TWDR action
1
1
1
Data byte has been
Load data byte or
0
0
1
transmitted; ACK has
been received
No TWDR action or
1
0
1
X
STOP condition will be transmitted
and TWSTO Flag will be rese
X
STOP condition followed by a START
condition will be transmitted and
TWSTO Flag will be reset
X
Data byte will be transmitted and
ACK or NOT ACK will be received
X
Repeated START will be transmitted
0x30
No TWDR action or
0
1
1
No TWDR action
1
1
1
Data byte has been
Load data byte or
0
0
1
transmitted; NOT ACK
has been received
No TWDR action or
1
0
1
X
STOP condition will be transmitted
and TWSTO Flag will be reset
X
STOP condition followed by a START
condition will be transmitted and
TWSTO Flag will be reset
X
Data byte will be transmitted and
ACK or NOT ACK will be received
X
Repeated START will be transmitted
0x38
No TWDR action or
0
1
1
No TWDR action
1
1
1
Arbitration lost in SLA+W No TWDR action or
0
0
1
or data bytes
No TWDR action
1
0
1
X
STOP condition will be transmitted
and TWSTO Flag will be reset
X
STOP condition followed by a START
condition will be transmitted and
TWSTO Flag will be reset
X
2-wire Serial Bus will be released and
not addressed Slave mode entered
X
A START condition will be
transmitted when the bus be-comes
free
25.7.2 Master Receiver Mode
In the Master Receiver mode, a number of data bytes are received from a Slave
Transmitter (for Slave see Figure 25-13 on page 392). In order to enter a Master mode,
a START condition must be transmitted. The format of the following address packet
determines whether Master Transmitter or Master Receiver mode is to be entered. If
SLA+W is transmitted, MT mode is entered, if SLA+R is transmitted, MR mode is
entered. All the status codes mentioned in this section assume that the prescaler bits
are zero or are masked to zero.
8266C-MCU Wireless-08/11
391