Rev. 1.3
203
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
Table 17.4. SMBus Status Decoding
Mode
Values Read
Current SMbus State
Typical Response Options
Values
Written
St
a
tu
s
Ve
c
to
r
AC
KRQ
ARB
LOST
AC
K
ST
A
ST
o
AC
K
Master T
ransmitt
e
r
1110
0
0
X A master START was generated.
Load slave a R/W
into SMB0DAT.
0
0
X
1100
0
0
0
A master data or address byte
was transmitted; NACK received.
Set STA to restart transfer.
1
0
X
Abort transfer.
0
1
X
0
0
1
A master data or address byte
was transmitted; ACK received.
Load next data byte into
SMB0DAT.
0
0
X
End transfer with STOP.
0
1
X
End transfer with STOP and
start another transfer.
1
1
X
Send repeated START.
1
0
X
Switch to Master Receiver
Mode (clear SI without writ-
ing new data to SMB0DAT).
0
0
X
Mast
er Receiver
1000
1
0
X
A master data byte was received;
ACK requested.
Acknowledge received byte;
Read SMB0DAT.
0
0
1
Send NACK to indicate last
byte, and send STOP.
0
1
0
Send NACK to indicate last
byte, and send STOP fol-
lowed by START.
1
1
0
Send ACK followed by
repeated START.
1
0
1
Send NACK to indicate last
byte, and send repeated
START.
1
0
0
Send ACK and switch to
Master Transmitter Mode
(write to SMB0DAT before
clearing SI).
0
0
1
Send NACK and switch to
Master Transmitter Mode
(write to SMB0DAT before
clearing SI).
0
0
0