146
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
Figure 74.
Formats and States in the Slave Transmitter Mode
S
SLA
R
A
DATA
A
$A8
$B8
A
$B0
Reception of the own
slave address and one or
more data bytes
Last data byte transmitted.
Arbitration lost as master
and addressed as slave
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 2-wire serial bus
P or S
DATA
$C0
DATA
A
A
$C8
P or S
All 1's
A
Table 45.
Status Codes for Miscellaneous States
Status
Code
(TWSR)
Status of the 2-wire
Serial Bus and 2-wire
Serial Hardware
Application Software Response
Next Action Taken by 2-wire
Serial Hardware
To/From TWDR
To TWCR
STA
STO
TWINT
TWEA
$F8
No relevant state
information available;
TWINT = “0”
No TWDR action
No TWCR action
Wait or proceed current transfer
$00
Bus error due to an
illegal START or STOP
condition
No TWDR action
0
1
1
X
Only the internal hardware is affected; no
STOP condition is sent on the bus. In all
cases, the bus is released and TWSTO is
cleared.