Fujitsu FR81S User Manual
CHAPTER 40: MULTI-FUNCTION SERIAL INTERFACE
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : MULTI-FUNCTION SERIAL INTERFACE
FUJITSU SEMICONDUCTOR CONFIDENTIAL
126
Bit name
Function
bit3 AL:
Arbitration lost
bit
"0" Read: No arbitration lost occurred
"1" Read: Arbitration lost occurred
This bit indicates an arbitration lost.
AL bit set conditions:
(1) When the data output in master mode and received data are different.
(2) You set "1" to the IBCR:MSS bit but the operation is still in slave mode.
(3) A repeat start condition was detected at the first bit of the second byte or later in
master mode.
(4) A stop condition was detected at the first bit of the second byte or later in master
mode.
(5) Trying to generate a repeat start condition but cannot do so in master mode.
(6) Trying to generate a stop condition but cannot do so in master mode.
AL bit reset conditions:
(1) Writing "1" to the IBCR:MSS bit
(2) Writing "0" to the IBSR:INT bit
(3) Writing "0" to SPC bit when AL="1" and SPC="1"
(4) I
2
C interface disable (ISMK:EN bit="0")
(5) Bus error detected (IBCR:BER bit="1")
bit2 RSC:
Repeat start
condition check
bit
"0" Read: No repeated start condition detected
"1" Read: Repeated start condition detected
This bit indicates that repeat start condition was detected in master mode or slave mode.
RSC bit set conditions
(1) A repeat start condition was detected after acknowledgement in master mode or slave
mode
RSC bit reset conditions:
(1) Writing "0" to the RSC bit
(2) Writing "1" to the IBCR:MSS bit
(3) I
2
C interface disable (ISMK:EN bit="0")
There will be no effect on the operation of writing "1" to this bit.
Notes:
⋅
If you do not respond with acknowledge when receiving data as the slave mode due to
the detection of the reserved address, this bit will not be set "1" next time the detection
of a repeat start condition occurred because it has already exited the slave mode.
⋅
For read-modify-write instructions, "1" will be read.
bit1 SPC:
Stop condition
check bit
"0" Read: No stop condition detected
"1" Read: (Master) stop condition detected or generation of arbitration lost at stop
condition output
"1" Read: (Slave) stop condition detected
This bit indicates that stop condition was detected in master mode or slave mode.
SPC bit set conditions:
(1) A stop condition was detected in master mode or slave mode
(2) An arbitration lost is generated on the stop condition generation in master mode
SPC bit reset conditions:
(1) Writing "0" to this bit
(2) Writing "1" to the IBCR:MSS bit
(3) I
2
C interface disable (ISMK:EN bit="0")
There will be no effect on the operation of writing "1" to this bit.
Notes:
⋅
If you do not respond with acknowledge when receiving data as the slave mode due to
the detection of the reserved address, this bit will not be set "1" next time the detection
of a stop condition occurred because it has already exited the slave mode.
⋅
For read-modify-write instructions, "1" will be read.
MB91520 Series
MN705-00010-1v0-E
1439