pca9673 NXP Semiconductors, pca9673 Datasheet - Page 11

• Manufacturer Part Number: pca9673
• Description: Remote 16-bit I/o Expander For Fm+ I2c-bus With Interrupt And Reset
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9673_1
Product data sheet
Fig 16. Write mode (output)
SDA
SCL
data output from port
P05 output voltage
P05 pull-up output current
P16 output voltage
P16 pull-up output current
INT
write to port
S A6
START condition
1
A5 A4 A3 A2 A1 A0 0
2
8.3 Reading from a port (Input mode)
slave address
3
4
first data byte is acknowledged by the PCA9673, the second data byte P17 to P10 is sent
by the master. Once again, the PCA9673 acknowledges the receipt of the data. Each 8-bit
data is presented on the port lines after it has been acknowledged by the PCA9673.
The number of data bytes that can be sent successively is not limited. After every two
bytes, the previous data is overwritten.
The first data byte in every pair refers to Port 0 (P07 to P00), whereas the second data
byte in every pair refers to Port 1 (P17 to P10). See
All ports programmed as input should be set to logic 1. To read, the master
(microcontroller) first addresses the slave device after it receives the interrupt. By setting
the last bit of the byte containing the slave address to logic 1 the Read mode is entered.
The data bytes that follow on the SDA are the values on the ports. If the data on the input
port changes faster than the master can read, this data may be lost.
Fig 15. Correlation between bits and ports
5
6
7
R/W
P07
8
07
9
A
acknowledge
from slave
P06 P05 P04 P03 P02 P01 P00
06
07
Remote 16-bit I/O expander for Fm+ I
P
05
06 1
P
Rev. 01 — 1 February 2007
first byte
04
data to port 0
P05
04
P
03
03
P
02
02
P
01
01
P
I
t
trt(pu)
d(rst)
00
P
00
A
acknowledge
from slave
A
17
P
t
v(Q)
P17
17
I
1
P16
OH
data A0 and B0 valid
15
P
data to port 1
P16 P15 P14 P13 P12 P11 P10
16
14
P
Figure
15
13
P
second byte
2
12
C-bus with interrupt and reset
14
P
15.
11
I
P
trt(pu)
13
10
P
12
A
acknowledge
from slave
data A0 and B0 valid
11
PCA9673
t
© NXP B.V. 2007. All rights reserved.
v(Q)
I
002aab634
OH
10
002aab632
A
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