Rainbow Electronics AT89C51SND1C - Manual (Page 167)

167
AT8xC51SND1C
4109E–8051–06/03
Table 136. Status for Master Transmitter Mode
Status
Code
SSSTA
Status of the TWI Bus
and TWI Hardware
Application Software Response
Next Action Taken by TWI Hardware To/From SSDAT
To SSCON
SSSTA SSSTO SSI SSAA
08h
A START condition has
been transmitted Write SLA+W
X 0 0 X
SLA+W will be transmitted.
10h
A repeated START
condition has been
transmitted
Write SLA+W
Write SLA+R
X
X
0
0
0
0
X
X
SLA+W will be transmitted.
SLA+R will be transmitted.
Logic will switch to master receiver mode
18h
SLA+W has been
transmitted; ACK has
been received
Write data Byte
No SSDAT action
No SSDAT action
No SSDAT action
0
1
0
1
0
0
1
1
0
0
0
0
X
X
X
X
Data Byte will be transmitted.
Repeated START will be transmitted.
STOP condition will be transmitted and SSSTO flag
will be reset.
STOP condition followed by a START condition will
be transmitted and SSSTO flag will be reset.
20h
SLA+W has been
transmitted; NOT ACK
has been received
Write data Byte
No SSDAT action
No SSDAT action
No SSDAT action
0
1
0
1
0
0
1
1
0
0
0
0
X
X
X
X
Data Byte will be transmitted.
Repeated START will be transmitted.
STOP condition will be transmitted and SSSTO flag
will be reset.
STOP condition followed by a START condition will
be transmitted and SSSTO flag will be reset.
28h
Data Byte has been
transmitted; ACK has
been received
Write data Byte
No SSDAT action
No SSDAT action
No SSDAT action
0
1
0
1
0
0
1
1
0
0
0
0
X
X
X
X
Data Byte will be transmitted.
Repeated START will be transmitted.
STOP condition will be transmitted and SSSTO flag
will be reset.
STOP condition followed by a START condition will
be transmitted and SSSTO flag will be reset.
30h
Data Byte has been
transmitted; NOT ACK
has been received
Write data Byte
No SSDAT action
No SSDAT action
No SSDAT action
0
1
0
1
0
0
1
1
0
0
0
0
X
X
X
X
Data Byte will be transmitted.
Repeated START will be transmitted.
STOP condition will be transmitted and SSSTO flag
will be reset.
STOP condition followed by a START condition will
be transmitted and SSSTO flag will be reset.
38h
Arbitration lost in
SLA+W or data Bytes
No SSDAT action
No SSDAT action
0
1
0
0
0
0
X
X
TWI bus will be released and not addressed slave
mode will be entered.
A START condition will be transmitted when the bus
becomes free.