PCA9550 Philips Semiconductors, PCA9550 Datasheet - Page 7

• Manufacturer Part Number: PCA9550
• Description: 2-bit I2C LED driver with programmable blink rates
• Manufacturer: Philips Semiconductors

Philips Semiconductors
Bus transactions
NOTES:
1. This figure assumes the command byte has previously been programmed with 00h.
2003 May 02
S
2-bit I
READ FROM
FROM PORT
DATA INTO
1
REGISTER
DATA OUT
WRITE TO
PORT
PORT
1
SDA
SDA
SCL
2
0
slave address
C LED driver with programmable blink rates
start condition
0
S
1
start condition
0
1
S
0
2
1
1
A0
3
acknowledge
from slave
0
slave address
1
R/W
0
4
0
0
slave address
A
DATA 1
5
0
0
0
6
0
0
0
A0
7
0
0
R/W
0
8
AI
A0
R/W
t
ph
Figure 11. READ input port register
A
0
acknowledge
from slave
9
1
Figure 10. READ from register
B2
0
Figure 9. WRITE to register
A
acknowledge
from slave
B1 B0
0
acknowledge
from slave
DATA 2
0
command byte
A
AI
at this moment master-transmitter
becomes master-receiver and
slave-receiver becomes
slave-transmitter
7
data from port
S
0
DATA 1
1
DATA 3
B2
1
B1
slave address
0
B0
0
A
acknowledge
from slave
t
ps
0
0
A
acknowledge
from master
A0
acknowledge
from slave
R/W
1
data to register
A
data from port
DATA 1
DATA 4
data from register
DATA 4
last byte
data from register
DATA
no acknowledge
from master
first byte
DATA
t
pv
PCA9550
A
acknowledge
from slave
no acknowledge
from master
auto-increment
register address
if AI = 1
DATA 1 VALID
NA
SW01098
acknowledge
from master
NA
Product data
SW01014
SW01095
P
stop
condition
P
A