At8xc51snd1c – Rainbow Electronics AT89C51SND1C User Manual
Page 168
168
AT8xC51SND1C
4109E–8051–06/03
Table 137. Status for Master Receiver 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+R
X
0
0
X
SLA+R will be transmitted.
10h
A repeated START
condition has been
transmitted
Write SLA+R
Write SLA+W
X
X
0
0
0
0
X
X
SLA+R will be transmitted.
SLA+W will be transmitted.
Logic will switch to master transmitter mode.
38h
Arbitration lost in
SLA+R or NOT ACK
bit
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.
40h
SLA+R has been
transmitted; ACK has
been received
No SSDAT action
No SSDAT action
0
0
0
0
0
0
0
1
Data Byte will be received and NOT ACK will be
returned.
Data Byte will be received and ACK will be returned.
48h
SLA+R has been
transmitted; NOT ACK
has been received
No SSDAT action
No SSDAT action
No SSDAT action
1
0
1
0
1
1
0
0
0
X
X
X
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.
50h
Data Byte has been
received; ACK has
been returned
Read data Byte
Read data Byte
0
0
0
0
0
0
0
1
Data Byte will be received and NOT ACK will be
returned.
Data Byte will be received and ACK will be returned.
58h
Data Byte has been
received; NOT ACK
has been returned
Read data Byte
Read data Byte
Read data Byte
1
0
1
0
1
1
0
0
0
X
X
X
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.