DS4520 Datasheet, PDF (10/10 Pages) Maxim Integrated Products – 9-Bit I2C Nonvolatile I/O Expander Plus Memory

9-Bit I²C Nonvolatile
I/O Expander Plus Memory
TYPICAL I²C WRITE TRANSACTION
MSB
LSB
MSB
LSB
MSB
LSB
START 1 0 1 0 A2 A1 A0 R/W ^SLAVE b7 b6 b5 b4 b3 b2 b1 b0 ^SLAVE b7 b6 b5 b4 b3 b2 b1 b0 ^SLAVE STOP
ACK
ACK
ACK
SLAVE
ADDRESS*
READ/
WRITE
REGISTER ADDRESS
DATA
*THE SLAVE ADDRESS IS DETERMINED BY ADDRESS PINS A0, A1, AND A2.
EXAMPLE I²C TRANSACTIONS (WHEN A0, A1, AND A2 ARE CONNECTED TO GND)
A) SINGLE BYTE WRITE
-WRITE I/O CONTROL 0
REGISTER TO 00h
A0h
F2h
START 1 0 1 0 0 0 0 0 ^SLAVE 1 1 1 1 0 0 1 0 ^SLAVE 0 0 0 0 0 0 0 0 ^SLAVE
ACK
ACK
ACK
STOP
B) SINGLE BYTE READ
-READ I/O STATUS 0 RESISTER
A0h
F8h
START
1 0100000
SLAVE
ACK
11111 000
SLAVE
ACK
REPEATED
START
A1h
1 0 1 0 0 0 0 1 ^SLAVE
ACK
DATA
I/O STATUS
MASTER
NACK
STOP
C) SINGLE BYTE WRITE
-WRITE PULLUP ENABLE 0
REGISTER TO FFh
A0h
F0h
FFh
START 1 0 1 0 0 0 0 0
SLAVE
ACK
11110 000
SLAVE
ACK
111 1 1 1 1 1
SLAVE
ACK
STOP
D) TWO BYTE WRITE
-WRITE I/O CONTROL 0 AND
I/O CONTROL 1 REGISTERS TO 00h
A0h
F2h
START
10100000
SLAVE
ACK
11110 010
SLAVE
ACK
00h
00000000
00h
SLAVE
ACK
00000000
SLAVE
ACK
STOP
D) TWO BYTE READ
-READ I/O STATUS 0 AND I/O
STATUS 1 RGISTERS
A0h
F8h
START 1 0 1 0 0 0 0 0
SLAVE
ACK
111 11000
SLAVE
ACK
A1h
DATA
REPEATED
START
1010 0001
SLAVE
ACK
I/O STATUS 0
MASTER
ACK
DATA
I/O STATUS 1
MASTER
NACK
STOP
Figure 3. I²C Communication Examples
See Figure 3 for a read example using the repeated
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 generates a stop condition.
Applications Information
Power-Supply Decoupling
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_CC
and GND pins of the IC to minimize lead inductance.
Chip Topology
TRANSISTOR COUNT: 14,398
SUBSTRATE CONNECTED TO GROUND
Package Information
For the latest package outline information, go to
www.maxim-ic.com/DallasPackInfo.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
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