PCA9553 Datasheet, PDF (12/26 Pages) NXP Semiconductors – 4-bit I2C LED driver with programmable blink rates

NXP Semiconductors
PCA9553
4-bit I²C-bus LED driver with programmable blink rates
V_DD
3.3 V
5V
V_DD
LEDn
LED
100 kΩ
V_DD
LED
LEDn
002aac189
002aac190
Fig 16. High value resistor in parallel with Fig 17. Device supplied by a lower voltage
the LED
9.2 Programming example
The following example shows how to set LED0 and LED1 off. It will then set LED2 to blink
at 1 Hz, 50 % duty cycle. LED3 will be set to blink at 4 Hz, 25 % duty cycle. PCA9553/01
is used in this example.
Table 11. Programming PCA9553
Program sequence
I²C-bus
START
S
PCA9553 address
C4h
PSC0 subaddress + Auto-Increment
11h
Set prescaler PSC0 to achieve a period of 1 second:
2Bh
Blink period = 1 = ^P-----^S---^C--₄--⁰-₄----⁺-----¹-
PSC0 = 43
Set PWM0 duty cycle to 50 %:
80h
2_---5_---6_-----–_-2---5P---6-W_------M_-----0_{-- = 0.5}
PWM0 = 128
Set prescaler PSC1 to achieve a period of 0.25 seconds:
0Ah
Blink period = 0.25 = ^P-----^S---^C--₄--¹-₄----⁺-----¹-
PSC1 = 10
Set PWM1 output duty cycle to 25 %:
C0h
2_---5_---6_-----–_-2---5P---6-W_------M_-----1_{-- = 0.25}
PWM1 = 192
Set LED0 on, LED1 off, LED2 set to blink at PSC0, PWM0, LED3 set to blink at E4h
PSC1, PWM1
STOP
P
PCA9553_6
Product data sheet
Rev. 06 — 29 December 2008
© NXP B.V. 2008. All rights reserved.
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