PCA9552 Philips Semiconductors, PCA9552 Datasheet - Page 6

• Manufacturer Part Number: PCA9552
• Description: 16-bit I2C LED driver with programmable blink rates
• Manufacturer: Philips Semiconductors

Philips Semiconductors
PWM0 — PWM REGISTER 0
The PWM0 register determines the duty cycle of BLINK0. The
outputs are LOW (LED off) when the count is less than the value in
PWM0 and HIGH when it is greater. If PWM0 is programmed with
00h, then the PWM0 output is always LOW.
The duty cycle of BLINK0 is: 256 – PWM0
PSC1 — FREQUENCY PRESCALER 1
PSC1 is used to program the period of PWM output.
The period of BLINK1
PWM1 — PWM REGISTER 1
The PWM1 register determines the duty cycle of BLINK1. The
outputs are LOW (LED off) when the count is less than the value in
PWM1 and HIGH when it is greater. If PWM1 is programmed with
00h, then the PWM1 output is always LOW.
The duty cycle of BLINK1 is: 256 – PWM1
LS0 — LED 0–3 SELECTOR
LS1 — LED 4–7 SELECTOR
LS2 — LED 8–11 SELECTOR
LS3 — LED 12–15 SELECTOR
The LSx LED select registers determine the source of the LED data.
2004 Oct 01
default
default
default
default
default
default
default
16-bit I
00 = Output is set LOW (LED on)
01 = Output is set Hi-Z (LED off – default)
10 = Output blinks at PWM0 rate
11 = Output blinks at PWM1 rate
bit
bit
bit
bit
bit
bit
bit
7
1
7
1
7
1
7
0
7
0
7
0
7
0
LED 15
LED 11
LED 3
LED 7
2
C LED driver with programmable blink rates
6
0
6
1
6
0
6
1
6
1
6
1
6
1
(PSC1
5
0
5
1
5
0
5
0
5
0
5
0
5
0
LED 10
LED 14
LED 2
LED 6
44
4
0
4
1
4
0
4
1
4
1
4
1
4
1
256
256
1)
3
0
3
1
3
0
3
0
3
0
3
0
3
0
LED 13
LED 1
LED 5
LED 9
2
0
2
1
2
0
2
1
2
1
2
1
2
1
1
0
1
1
1
0
1
0
1
0
1
0
1
0
LED 12
LED 0
LED 4
LED 8
0
0
0
1
0
0
0
1
0
1
0
1
0
1
6
PINS USED AS GENERAL PURPOSE I/Os
LED pins not used to control LEDs can be used as general purpose
I/Os.
For use as input: Set LEDx to high-impedance (01) and then read
the pin state via the input register.
For use as output: Connect external pull-up resistor to the pin and
size it according to the DC recommended operating characteristics.
LED output pin is HIGH when the output is programmed as
high-impedance, and LOW when the output is programmed LOW
through the “LED selector” register. The output can be pulse-width
controlled when PWM0 or PWM1 are used.
POWER-ON RESET
When power is applied to V
the PCA9552 in a reset condition until V
this point, the reset condition is released and the PCA9552 registers
are initialized to their default states, all the outputs in the off state.
Thereafter, V
EXTERNAL RESET
A reset can be accomplished by holding the RESET pin LOW for a
minimum of t
be held in their default state until the RESET input is once again
HIGH.
This input requires a pull-up resistor to V
used.
W
DD
. The PCA9552 registers and I
must be lowered below 0.2 V to reset the device.
DD
, an internal Power-On Reset holds
DD
DD
has reached V
if no active connection is
2
C state machine will
PCA9552
Product data sheet
POR
. At