ds4550et-r Maxim Integrated Products, Inc., ds4550et-r Datasheet - Page 17

• Manufacturer Part Number: ds4550et-r
• Description: Ds4550 I?c And Jtag Nonvolatile 9-bit I/o Expander Plus Memory
• Manufacturer: Maxim Integrated Products, Inc.

See
start condition to specify the starting memory location.
Reading Multiple Bytes from a Slave: The read oper-
ation can be used to read multiple bytes with a single
transfer. When reading bytes from the slave, the master
simply ACKs the data byte if it desires to read another
byte before terminating the transaction. After the mas-
ter reads the last byte, it must NACK to indicate the end
of the transfer and generate a stop condition.
Figure
D)
A)
B)
C)
D)
TYPICAL I
EXAMPLE I
START
TWO BYTE READ
-READ I/O STATUS 0 AND I/O
STATUS 1 RGISTERS
SINGLE BYTE WRITE
-WRITE I/O CONTROL 0
REGISTER TO 00h
SINGLE BYTE READ
-READ I/O STATUS 0 RESISTER
SINGLE BYTE WRITE
-WRITE PULLUP ENABLE 0
REGISTER TO FFh
TWO BYTE WRITE
-WRITE I/O CONTROL 0 AND
I/O CONTROL 1 REGISTERS TO 00h
Figure
6. I
2
MSB
C WRITE TRANSACTION
2
2
1
C TRANSACTIONS (WHEN A0, A1, AND A2 ARE CONNECTED TO GND)
C Communication Examples
6 for a read example using the repeated
0
1
ADDRESS*
SLAVE
0
A2
START
START
START 1 0 1 0 0 0 0 0
START
START
A1
1 0 1 0 0 0 0 0
1 0 1 0 0 0 0 0
1 0 1 0 0 0 0 0
1 0 1 0 0 0 0 0
A0
A0h
A0h
A0h
A0h
A0h
WRITE
READ/
R/W
LSB
I
2
SLAVE
ACK
C and JTAG Nonvolatile 9-Bit I/O
____________________________________________________________________
SLAVE
SLAVE
SLAVE
SLAVE
SLAVE
ACK
ACK
ACK
ACK
ACK
MSB
b7
1 1 1 1 0 0 1 0
1 1 1 1 1 0 0 0
1 1 1 1 1 0 0 0
1 1 1 1 0 0 1 0
1 1 1 1 0 0 0 0
b6
F2h
F8h
F0h
F2h
F8h
b5
REGISTER ADDRESS
*THE SLAVE ADDRESS IS DETERMINED BY ADDRESS PINS A0, A1, AND A2.
b4
SLAVE
SLAVE
SLAVE
SLAVE
SLAVE
ACK
ACK
ACK
ACK
ACK
b3
0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 0
REPEATED
REPEATED
b2
START
START
FFh
00h
Expander Plus Memory
To achieve best results, it is highly recommended that a
decoupling capacitor is used on the IC power-supply
pins. Typical values of decoupling capacitors are 0.01µF
and 0.1µF. Use a high-quality, ceramic, surface-mount
capacitor, and mount it as close as possible to the V
and GND pins of the IC to minimize lead inductance.
b1
LSB
b0
1 0 1 0 0 0 0 1
1 0 1 0 0 0 0 1
SLAVE
SLAVE
SLAVE
ACK
ACK
ACK
A1h
A1h
SLAVE
ACK
0 0 0 0 0 0 0 0
STOP
STOP
MSB
00h
b7
SLAVE
SLAVE
ACK
ACK
Applications Information
b6
I/O STATUS 0
I/O STATUS
SLAVE
b5
ACK
DATA
DATA
Power Supply Decoupling
b4
DATA
STOP
b3
MASTER
MASTER
NACK
ACK
b2
b1
I/O STATUS 1
STOP
DATA
LSB
b0
SLAVE
ACK
MASTER
NACK
STOP
STOP
CC
17