OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

PCA9673DB,118

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33
PCA9673 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 29 September 2011 16 of 33
NXP Semiconductors
PCA9673
Remote 16-bit I/O expander for Fm+ I
2
C-bus with interrupt and reset
9. Characteristics of the I
2
C-bus
The I
2
C-bus is for 2-way, 2-line communication between different ICs or modules. The two
lines are a serial data line (SDA) and a serial clock line (SCL). Both lines must be
connected to a positive supply via a pull-up resistor when connected to the output stages
of a device. Data transfer may be initiated only when the bus is not busy.
9.1 Bit transfer
One data bit is transferred during each clock pulse. The data on the SDA line must remain
stable during the HIGH period of the clock pulse as changes in the data line at this time
will be interpreted as control signals (see Figure 18
).
9.1.1 START and STOP conditions
Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW
transition of the data line while the clock is HIGH is defined as the START condition (S).
A LOW-to-HIGH transition of the data line while the clock is HIGH is defined as the STOP
condition (P) (see Figure 19
).
9.2 System configuration
A device generating a message is a ‘transmitter’; a device receiving is the ‘receiver’. The
device that controls the message is the ‘master’ and the devices which are controlled by
the master are the ‘slaves’ (see Figure 20
).
Fig 18. Bit transfer
mba607
data line
stable;
data valid
change
of data
allowed
SDA
SCL
Fig 19. Definition of START and STOP conditions
mba608
SDA
SCL
P
STOP condition
S
START condition
PCA9673 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 29 September 2011 17 of 33
NXP Semiconductors
PCA9673
Remote 16-bit I/O expander for Fm+ I
2
C-bus with interrupt and reset
9.3 Acknowledge
The number of data bytes transferred between the START and the STOP conditions from
transmitter to receiver is not limited. Each byte of eight bits is followed by one
acknowledge bit. The acknowledge bit is a HIGH level put on the bus by the transmitter,
whereas the master generates an extra acknowledge related clock pulse.
A slave receiver which is addressed must generate an acknowledge after the reception of
each byte. Also a master must generate an acknowledge after the reception of each byte
that has been clocked out of the slave transmitter. The device that acknowledges has to
pull down the SDA line during the acknowledge clock pulse, so that the SDA line is stable
LOW during the HIGH period of the acknowledge related clock pulse; set-up and hold
times must be taken into account.
A master receiver must signal an end of data to the transmitter by not generating an
acknowledge on the last byte that has been clocked out of the slave. In this event, the
transmitter must leave the data line HIGH to enable the master to generate a STOP
condition.
Fig 20. System configuration
002aaa966
MASTER
TRANSMITTER/
RECEIVER
SLAVE
RECEIVER
SLAVE
TRANSMITTER/
RECEIVER
MASTER
TRANSMITTER
MASTER
TRANSMITTER/
RECEIVER
SDA
SCL
I
2
C-BUS
MULTIPLEXER
SLAVE
Fig 21. Acknowledgement on the I
2
C-bus
002aaa987
S
START
condition
9821
clock pulse for
acknowledgement
not acknowledge
acknowledge
data output
by transmitter
data output
by receiver
SCL from master
PCA9673 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 29 September 2011 18 of 33
NXP Semiconductors
PCA9673
Remote 16-bit I/O expander for Fm+ I
2
C-bus with interrupt and reset
10. Application design-in information
10.1 Bidirectional I/O expander applications
In the 8-bit I/O expander application shown in Figure 22, P00 and P01 are inputs, and P02
to P07 are outputs. When used in this configuration, during a write, the input (P00 and
P01) must be written as HIGH so the external devices fully control the input ports. The
desired HIGH or LOW logic levels may be written to the I/Os used as outputs (P02 to
P07). During a read, the logic levels of the external devices driving the input ports (P00
and P01) and the previous written logic level to the output ports (P02 to P07) will be read.
The GPIO also has an interrupt line (INT
) that can be connected to the interrupt logic of
the microprocessor. By sending an interrupt signal on this line, the remote I/O informs the
microprocessor that there is incoming data or a change of data on its ports without having
to communicate via the I
2
C-bus.
10.2 High current-drive load applications
The GPIO has a maximum sinking current of 25 mA per bit. In applications requiring
additional drive, two port pins in the same octal may be connected together to sink up to
50 mA current. Both bits must then always be turned on or off together. Up to 8 pins (one
octal) can be connected together to drive 200 mA.
Fig 22. Bidirectional I/O expander application
002aac310
V
DD
temperature sensor
battery status
control for latch
control for switch
control for audio
control for camera
control for MP3
P00
P01
P02
P03
P04
P05
P06
P07
V
DD
SDA
SCL
INT
AD0
AD1
CORE
PROCESSOR
V
DD
RESET
Fig 23. High current-drive load application
002aac311
V
DD
P00
P01
P02
P03
P04
P05
P06
P07
V
DD
SDA
SCL
INT
CORE
PROCESSOR
V
DD
LOAD
AD0
AD1
RESET
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27P28-P30P31-P33

PCA9673DB,118

Mfr. #:
Buy PCA9673DB,118
Manufacturer:
NXP Semiconductors
Description:
IC I/O EXPANDER I2C 16B 24SSOP
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet