PCA9554_15 Datasheet, PDF (20/34 Pages) Texas Instruments – SMBus I/O Expander With Interrupt Output

PCA9554
SCPS128C – JULY 2006 – REVISED JUNE 2014
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Slave Address
ACK From
Slave
ACK From
Slave
Slave Address
ACK From
ACK From
Slave ^{Data from Register} Master
S 0 1 0 0 A2 A1 A0 0 A
R/W
Command Byte
A S 0 1 0 0 A2 A1 A0 1 A
R/W
Data
A
<br/>
Figure 26. Read From Register
NACK From
Data from Register _Master
Data
Last Byte
NA P
SCL
SDA
Read From
Port
Data Into
Port
12 345678 9
Slave Address
Data From Port
S 0 1 0 0 A2 A1 A0 1 A
Data 1
Start
Condition
R/W
ACK From
Slave
Data 2
Data 3
t_ph
t_ps
Data From Port
A
Data 4
NA P
ACK From
Master
NACK From
Master
Stop
Condition
Data 4
Data 5
INT
t_iv
t_ir
A. This figure assumes the command byte has previously been programmed with 00h.
B. Transfer of data can be stopped at any moment by a Stop condition.
C. This figure eliminates the command byte transfer, a restart, and slave address call between the initial slave address
call and actual data transfer from P port. See Figure 26 for these details.
Figure 27. Read From Input Port Register
20
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