PRELIMINARY
Notice. This is not a final specification.
Some parametric limits are subject to change.
MITSUBISHI ICs (AV COMMON)
M52791SP/FP
AV SWITCH with I2C BUS CONTROL
I C BUS
I
2
C BUS(Inter IC BUS)is multi master bus system developed by PHILIPS . Two wires ( SDA - serial data,
SCL - serial clock ) realize functions of start , stop , transferring data , synchronization and arbitration. The
output stages of device connected to the bus must have an open drain or open collector in order to perform the
wired-AND function .
2
SDA
A
MSB
SCL
S
P
A
MSB
LSB
LSB
1
2
3
4
5
6
7
8
9
1
2
9
S ; Start condition, a high to low transition of the SDA line while SCL is high
P ; Stop condition, a low to high transition of the SDA line while SCL is high
A ; Acknownledge
Every byte put on the SDA line must be 8-bits long . Each byte has to be followed by an acknowledge bit. Data
is transferred with the most significant bit (MSB ) first . The data on the SDA line must be stable during the
HIGH period of the clock . The HIGH or LOW state of the data line can only change when the clock signal on
the SCL line is LOW .
CONTROL
This IC controls 2-channel switchs with 2-byte data ( DATA1 and DATA2 ) . Video switches are
controled by DATA1 , audio switches are controled by DATA2 .
S
SLAVE ADDRESS A
DATA1
A
DATA2
A
P
S : Start
A : Acknowledge
P : Stop
SLAVE ADDRESS
1
0
0
1
0
0
X
0
R/W bit
Usually ` 0 ` ( W : Master transmitter transmits to slave
receiver )
Possible to select
22PIN : Hi : 1,Lo : 0
6 -10
AUG.'98
MITSUBISHI
MITSUBISHI [ MITSUBISHI ELECTRIC SEMICONDUCTOR ]
