Table 171. Status for Slave Transmitter Mode
Application Software Response
To SSCON
SSSTO SSI
Status of the TWI Bus
and TWI Hardware
Status
Code
SSSTA
To/From SSDAT
SSSTA
SSAA Next Action Taken by TWI Hardware
Write data Byte
X
0
0
0
0
0
1
Last data Byte will be transmitted.
Own SLA+R has been
received; ACK has
been returned
A8h
B0h
Write data Byte
Write data Byte
X
Data Byte will be transmitted.
Arbitration lost in
Last data Byte will be transmitted.
X
X
0
0
0
0
0
1
SLA+R/W as master;
own SLA+R has been
received; ACK has
been returned
Write data Byte
Data Byte will be transmitted.
Data Byte in SSDAT
has been transmitted;
ACK has been
Write data Byte
Write data Byte
Last data Byte will be transmitted.
Data Byte will be transmitted.
X
X
0
0
0
0
0
1
B8h
received
No SSDAT action
No SSDAT action
Switched to the not addressed slave mode; no
recognition of own SLA or GCA.
0
0
0
0
0
0
0
1
Switched to the not addressed slave mode; own
SLA will be recognized; GCA will be recognized if
SSGC = logic 1.
Data Byte in SSDAT
has been transmitted;
NOT ACK has been
received
No SSDAT action
No SSDAT action
Switched to the not addressed slave mode; no
recognition of own SLA or GCA. A START condition
will be transmitted when the bus becomes free.
C0h
1
1
0
0
0
0
0
1
Switched to the not addressed slave mode; own
SLA will be recognized; GCA will be recognized if
SSGC = logic 1. A START condition will be
transmitted when the bus becomes free.
No SSDAT action
No SSDAT action
Switched to the not addressed slave mode; no
recognition of own SLA or GCA.
0
0
0
0
0
0
0
1
Switched to the not addressed slave mode; own
SLA will be recognized; GCA will be recognized if
SSGC = logic 1.
Last data Byte in
SSDAT has been
transmitted
(SSAA= 0); ACK has
been received
No SSDAT action
No SSDAT action
Switched to the not addressed slave mode; no
recognition of own SLA or GCA. A START condition
will be transmitted when the bus becomes free.
C8h
1
1
0
0
0
0
0
1
Switched to the not addressed slave mode; own
SLA will be recognized; GCA will be recognized if
SSGC = logic 1. A START condition will be
transmitted when the bus becomes free.
Table 172. Status for Miscellaneous States
Application Software Response
Status
To SSCON
Code Status of the TWI Bus
SSSTA and TWI Hardware
To/From SSDAT
SSSTA
SSSTO
SSI
SSAA Next Action Taken by TWI Hardware
No relevant state
No SSDAT action
Wait or proceed current transfer.
F8h
00h
information available;
SSI = 0
No SSCON action
Bus error due to an
illegal START or STOP
condition
No SSDAT action
Only the internal hardware is affected, no STOP
condition is sent on the bus. In all cases, the bus is
released and SSSTO is reset.
0
1
0
X
194
AT8xC51SND2C
4341D–MP3–04/05
ATMEL [ ATMEL ]
