PCA9531 Philips Semiconductors (Acquired by NXP), PCA9531 Datasheet - Page 10

• Manufacturer Part Number: PCA9531
• Description: 8-bit I2C Led Dimmerthe PCA9531 is an 8-bit i C And Smbus I/o Expander Optimized For Dimming Leds in 256 Discrete Steps For Red/green/blue (RGB) Color Mixing And Back Light Applications. The PCA9531 Contains an Internal Oscillator With Two User Progr
• Manufacturer: Philips Semiconductors (Acquired by NXP)

Philips Semiconductors
Programming example
The following example will show how to set LED0 to LED3 on. It will
then set LED4 and LED5 to blink at 1 Hz at a 50% duty cycle. LED6
and LED7 will be set to be dimmed at 25% of their maximum
brightness (duty cycle = 25%).
Table 1.
2003 Nov 10
Start
PCA9531 address with A0-A2 = low
PSC0 subaddress + auto-increment
Set prescaler PSC0 to achieve a period of 1 second:
Set PWM0 duty cycle to 50%:
Set prescaler PCS1 to dim at max frequency:
Set PWM1 output duty cycle to 25%:
Set LED0 to LED3 on
Set LED4 and 5 to PWM0, and LED6 or 7 to PWM1
Stop
8-bit I
PWM1
256
PWM0
Blink period + 1 + PSC0 ) 1
256
Blink period + max
2
+ 0.25
PWM1 = 64
C LED dimmer
+ 0.5
PWM0 = 128
PSC0 = 151
PSC1 = 0
152
I
S
C0h
11h
97h
80h
00h
40h
55h
FAh
P
2
C-bus
10
PCA9531
Product data