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IDT I2C Bus Interface
I2C Register Description
79RC32438 User Reference Manual
15 - 3
November 4, 2002
Notes
I
2
C Bus Data Input Register
Figure 15.3 I
2
C Bus Data Input Register (I2CDI)
MEN
Description:
Master Enable.
When the bus prescalar clock is running and this bit is set, the I
2
C bus master
interface is enabled. When this bit is cleared, the I
2
C bus master interface is disabled and all
commands written to the I2CMCMD register are ignored. When disabled, the SLC and SDA pins
are tri-stated by the I
2
C bus master interface. Disabling and then enabling the master interface
causes all logic associated with the master interface to be reset.
Initial Value:
0x0
Read Value:
Previous value written
Write Effect:
Modify value
SEN
Description:
Slave Enable.
When the bus prescalar clock is running and this bit is set, the I
2
C bus slave inter-
face is enabled. When this bit is cleared, the slave is disabled. When disabled, the slave does
not respond to any operations and the SLC and SDA pins are tri-stated. Disabling and then
enabling the slave interface causes all logic associated with the slave interface to be reset.
Initial Value:
0x0
Read Value:
Previous value written
Write Effect:
Modify value
IOM
Description:
Ignore Other Masters.
When this bit is set, the I
2
C bus master interface will arbitrate for the I
2
C
bus but will assume that it always wins arbitration. This mode is used for testing and may be set
in single master systems.
When this bit is cleared, the I
2
C bus master will arbitrate for the I
2
C bus, as outlined in
The I
2
C-
bus Specification, Version 2.0
, December 1998, Philips Semiconductor.
Initial Value:
0x0
Read Value:
Previous value written
Write Effect:
Modify value
DATA
Description:
Data.
This field is used to receive data from the I
2
C bus and always contains the last byte
present on the I
2
C bus. The most significant bit of this field contains the first bit received from the
I
2
C bus.
Initial Value:
Undefined
I2CDI
0
31
DATA
0
24
8