Rev. 1.0, 02/00, page 479 of 1141
Table 23.3
Flags and Transfer States
MST
TRS
BBSY ESTP
STOP IRTR
AASX AL
AAS
ADZ
ACKB State
1/0
1/0
0
0
0
0
0
0
0
0
0
Idle state (flag clearing
required)
1
1
0
0
0
0
0
0
0
0
0
Start condition
issuance
1
1
1
0
0
1
0
0
0
0
0
Start condition
established
1
1/0
1
0
0
0
0
0
0
0
0/1
Master mode wait
1
1/0
1
0
0
1
0
0
0
0
0/1
Master mode
transmit/receive end
0
0
1
0
0
0
1/0
1
1/0
1/0
0
Arbitration lost
0
0
1
0
0
0
0
0
1
0
0
SAR match by first
frame in slave mode
0
0
1
0
0
0
0
0
1
1
0
General call address
match
0
0
1
0
0
0
1
0
0
0
0
SARX match
0
1/0
1
0
0
0
0
0
0
0
0/1
Slave mode
transmit/receive end
(except after SARX
match)
0
0
1/0
1
1
1
0
0
0
0
1
0
1
1
0
0
0
0
0
0
0
1
Slave mode
transmit/receive end
(after SARX match)
0
1/0
0
1/0
1/0
0
0
0
0
0
0/1
Stop condition
detected
Bit 0
Start Condition/Stop Condition Prohibit (SCP): Controls the issuing of start and stop
conditions in master mode. To issue a start condition, write 1 in BBSY and 0 in SCP. A
retransmit start condition is issued in the same way. To issue a stop condition, write 0 in BBSY
and 0 in SCP. This bit is always read as 1. If 1 is written, the data is not stored.
Bit 0
SCP
Description
0
Writing 0 issues a start or stop condition, in combination with the BBSY flag
1
Reading always returns a value of 1
(Initial value)
Writing is ignored