CAT9532 ONSEMI [ON Semiconductor], CAT9532 Datasheet - Page 10

• Manufacturer Part Number: CAT9532
• Description: 16-bit Programmable LED Dimmer with I2C Interface
• Manufacturer: ONSEMI [ON Semiconductor]

FROM PORT
REGISTER
WRITE TO
DATA OUT
Note: Transfer can be stopped at any time by a STOP condition.
S
CAT9532
Write Operations
Data is transmitted to the CAT9532 registers using the
write sequence shown in Figure 6.
If the AI bit from the command byte is set to “1”, the
CAT9532
sequentially. After sending data to one register, the
next data byte will be sent to the next register
sequentially addressed.
Read Operations
The CAT9532 registers are read according to the
timing diagrams shown in Figure 7 and Figure 8. Data
from the register, defined by the command byte, will
be sent serially on the SDA line.
After the first byte is read, additional data bytes may
be read when the auto-increment flag, AI, is set. The
additional data byte will reflect the data read from the
next register sequentially addressed by the (B3 B2 B1
B0) bits of the command byte.
When reading Input Port Registers (Figure 8), data is
clocked into the register on the failing edge of the
acknowledge clock pulse. The transfer is stopped
when the master will not acknowledge the data byte
received and issue the STOP condition.
Figure 6. Write to Register Timing Diagram
Figure 7. Read from Register Timing Diagram
Doc. No. MD-9001 Rev. E
SDA
SCL
1
1
Start Condition
S
Slave Address
0
1
1
0
2
1
internal
A2 A1 A0
Slave Address
3
0
4
0
A2 A1 A0
5
Acknowledge
R/W
From Slave
0
registers
6
A
7
R/W Acknowledge
8
0
A
9
From Slave
COMMAND BYTE
can
0
0
0
Command Byte
be
AI
B3 B2 B1 B0
written
Acknowledge
From Slave
At This Moment Master-Transmitter
A
Becomes Master-receiver and
S
10
Slave-Receiver Becomes
A
1
Acknowledge
From Slave
LED Pins Used as General Purpose I/O
Any LED pins not used to drive LEDs can be used as
general purpose input/output, GPIO.
When used as input, the user should program the
corresponding LED pin to Hi-Z (“00” for the LSx
register bits). The pin state can be read via the
Input Register according to the sequence shown in
Figure 8.
For use as output, an external pull-up resistor should
be connected to the pin. The value of the pull-up
resistor is calculated according to the DC operating
characteristics. To set the LED output high, the user
has to program the output Hi-Z writing “00” into the
corresponding LED Selector (LSx) register bits. The
output pin is set low when the LED output is
programmed low through the LSx register bits (“01” in
LSx register bits).
1
Slave-Transmitter
Slave Address
0
Data To Register 1
0
DAT
A2 A1 A0
A
1
Acknowledge
R/W
From Slave
1
MSB
t
pv
A
Data From Register
MSB
A
Acknowledge
From Slave
Characteristics subject to change without notice
Last Byte
Data From Register
DATA
Register Address
First Byte
Data To Register 2
Auto-increment
© 2010 SCILLC. All rights reserved
DATA
If Al = 1
LSB
No Acknowledge
From Master
NA
Acknowledg
From Master
LSB
P
1.0
A
A
e