Figure 91. Formats and States in the Slave Receiver Mode
Reception of the own
S
SLA
W
A
DATA
A
DATA
A
P or S
slave address and one or
more data bytes. All are
acknowledged
$60
$80
$80
A
$A0
Last data byte received
is not acknowledged
P or S
$88
Arbitration lost as master
and addressed as slave
A
$68
A
Reception of the general call
address and one or more data
bytes
General Call
DATA
A
DATA
A
P or S
$70
$90
$90
A
$A0
Last data byte received is
not acknowledged
P or S
$98
Arbitration lost as master and
addressed as slave by general call
A
$78
Any number of data bytes
and their associated acknowledge bits
From master to slave
From slave to master
DATA
A
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
n
Slave Transmitter Mode
In the Slave Transmitter mode, a number of data bytes are transmitted to a master
receiver (see Figure 92). All the status codes mentioned in this section assume that the
prescaler bits are zero or are masked to zero.
Figure 92. Data Transfer in Slave Transmitter Mode
VCC
Device 1
SLAVE
TRANSMITTER
Device 2
MASTER
RECEIVER
Device 3
Device n
R1
R2
........
SDA
SCL
To initiate the Slave Transmitter mode, TWAR and TWCR must be initialized as follows:
TWAR
TWA6
TWA5
TWA4
TWA3
TWA2
TWA1
TWA0
TWGCE
Value
Device’s Own Slave Address
192
ATmega32(L)
2503J–AVR–10/06
ATMEL [ ATMEL ]
