HD64F2145 Datasheet, PDF (446/829 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

Bit Bit Name Initial Value R/W
2 BBSY
0
R/W
0 SCP
1
W
Description
Bus Busy
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 condition]
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.
The SCP bit is always read as 1. If 0 is written, the data is
not stored.
Rev. 2.0, 08/02, page 406 of 788