MB89960 series
CHAPTER 12 I2C Interface
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12
Table 12.3.2 I2C Bus Control Register (IBCR) Bits
NO.
Bit
Function
bit7
BER:
Bus error interrupt
request bit
This bit is used to clear the bus error interrupt and to determine
whether bus error is detected.
Writing “0” to this bit clears the bus error interrupt.
Writing “1” to this bit has no effect and this bit does not change.
This bit is set to “1” when during data transfer, inappropriate
START or STOP condition is detected.
When this bit is set, the interrupt enable bit in CCR register is
cleared, I2C interface goes into halt mode and terminates the
data transfer.
bit6
BEIE:
Bus error interrupt
enable bit
This bit is used to enable output of bus error interrupt request
(BEIE = “1”) or disable bus error interrupt request (BEIE = “0”).
When this bit is set and BER = “1”, interrupt request is sent to
CPU.
bit5
SCC:
Start condition
continue bit
This bit is used to generate repeated START condition in
master mode (SCC = “1”).
Writing “0” to this bit has no effect and this bit does not change.
Reading this bit is always “0”.
Caution:1) Do not write SCC = “1” and MSS = “0” simultaneously.
2) When both INT = “0” and SCC is written “1”, SCC bit
has higher priority and START condition is generated.
bit4
MSS:
Master slave select
bit
This bit selects slave (MSS = “0”) or master mode (MSS = “1”).
Writing “0” to this bit change the I2C interface to slave mode
after current data transfer is completed (STOP condition is
generated).
Writing “1” to this bit change the I2C interface to master mode,
then generate START condition and initiate data transmit.
In master transmit, when arbitration lost occurs, this bit is
cleared and change to slave mode.
Caution:1) Do not write SCC = “1” and MSS = “0” simultaneously.
2) When INT is cleared and MSS is written “0”, MSS bit
has higher priority and STOP condition is generated.
bit3
ACK:
Acknowledge
enable bit
This bit is used to enable output of acknowledge bit (ACK = “1”)
or disable acknowledge bit (ACK = “0”) at the 9th clock during
data receive.
This bit is ignored when calling address is received in slave
mode. So the acknowledge bit must be sent out when the
calling address is matched with its own specific address.
bit2
GCAA:
General call
address
acknowledge enable
bit
This bit is set to enable output of general call address
acknowledge bit during slave receive.