Rainbow Electronics ATmega32L - Manual (Page 187)

187
ATmega32(L)
2503C–AVR–10/02
Figure 89. Formats and States in the Master Receiver Mode
Slave Receiver Mode In the Slave Receiver mode, a number of data bytes are received from a master trans-
mitter (see Figure 90). All the status codes mentioned in this section assume that the
prescaler bits are zero or are masked to zero.
Figure 90. Data Transfer in Slave Receiver Mode
To initiate the Slave Receiver mode, TWAR and TWCR must be initialized as follows:
S SLA R A DATA A
$08 $40 $50
SLA R
$10
A P
$48
A or A
$38
Other master
continues
$38
Other master
continues
W
A
$68
Other master
continues
$78 $B0 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
P DATA A
$58
A
R S
TWAR TWA6 TWA5 TWA4 TWA3 TWA2 TWA1 TWA0 TWGCE
Value Device’s Own Slave Address
Device 3 Device n
SDA
SCL
........ R1 R2
V
CC
Device 2
MASTER
TRANSMITTER
Device 1
SLAVE
RECEIVER