NXP Semiconductors
PCA9533
4-bit I2C-bus LED dimmer
8.2 Programming example
The following example will show how to set LED0 and LED1 off. It will set LED2 to blink at
1 Hz at a 50 % duty cycle. LED3 will be set to be dimmed at 25 % of their maximum
brightness (duty cycle = 25 %). PCA9533/01 is used in this example.
Table 11. Programming PCA9533
Program sequence
START
PCA9533 address
PSC0 subaddress + Auto-Increment
Set prescaler PSC0 to achieve a period of 1 second:
Blink period = 1 = P-----S---C----0-----+-----1-
152
PSC0 = 151
Set PWM0 duty cycle to 50 %:
P-----W2---5--M-6-----0- = 0.5
PWM0 = 128
Set prescaler PCS1 to dim at maximum frequency:
Blink period = max
PSC1 = 0
Set PWM1 output duty cycle to 25 %:
P-----W2---5--M-6-----1- = 0.25
PWM1 = 64
Set LED0 on, LED1 off; LED2 set to blink at PSC0, PWM0; LED3 set to blink at
PSC1, PWM1
STOP
I2C-bus
S
C4h
11h
97h
80h
00h
40h
E1h
P
9. Limiting values
Table 12. Limiting values
In accordance with the Absolute Maximum Rating System (IEC 60134).
Symbol Parameter
Conditions
Min
Max Unit
VDD
VI/O
IO(LEDn)
ISS
Ptot
Tstg
Tamb
supply voltage
voltage on an input/output pin
output current on pin LEDn
ground supply current
total power dissipation
storage temperature
ambient temperature
operating
−0.5
+6.0 V
VSS − 0.5 5.5
V
-
25
mA
-
100
mA
-
400
mW
−65
+150 °C
−40
+85
°C
PCA9533_3
Product data sheet
Rev. 03 — 27 April 2009
© NXP B.V. 2009. All rights reserved.
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