HD64F2168 Datasheet, PDF (488/874 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer

Initial
Bit Bit Name Value
2
BBSY
0
0
SCP
1
R/W Description
R/W*³ Bus Busy
W _{Start Condition/Stop Condition Prohibit}
In master mode
• Writing 0 in BBSY and 0 in SCP: A stop condition is
issued
• Writing 1 in BBSY and 0 in SCP: A start condition and
a restart condition are issued
In slave mode
• Writing to the BBSY flag is disabled.
[BBSY setting condition]
• When the SDA level changes from high to low under
the condition of SCL = high, assuming that the start
condition has been issued.
[BBSY clearing conditions]
• When the SDA level changes from low to high under
the condition of SCL = high, assuming that the stop
condition has been issued.
To issue a start/stop condition, use the MOV instruction.
The I²C bus interface must be set in master transmit mode
before the issue of a start condition. Set MST to 1 and
TRS to 1 before writing 1 in BBSY and 0 in SCP.
The BBSY flag can be read to check whether the I²C bus
(SCL, SDA) is busy or free.
Rev. 3.00, 03/04, page 448 of 830