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A REPEATED START condition is generated by writing the following value to TWCR:
After a repeated START condition (state 0x10) the Two-wire Serial Interface can access the
same slave again, or a new slave without transmitting a STOP condition. Repeated START
enables the master to switch between slaves, Master Transmitter mode and Master Receiver
mode without losing control over the bus.
Figure 18-14. Formats and States in the Master Receiver Mode
TWCR TWINT TWEA TWSTA TWSTO TWWC TWEN – TWIE
value 1
X10X10 X
S SLA R A DATA A
0x08
0x40 0x50
SLA R
0x10
AP
0x48
A or A
0x38
Other master
continues
0x38
Other master
continues
W
A
0x68
Other master
continues
0x78 0xB0
To corresponding
states in slave mode
MR
MT
Successfull
reception
from a slave
receiver
Next transfer
started with a
repeated start
condition
Not acknowledge
received after the
slave address
Arbitration lost in slave
address or data byte
Arbitration lost and
addressed as slave
DATA A
n
From master to slave
From slave to master
Any number of data bytes
and their associated acknowledge bits
This number (contained in TWSR) corresponds
to a defined state of the Two-wire Serial Bus. The
prescaler bits are zero or masked to zero
PDATA A
0x58
A
R
S
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