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User manual Rev. 1 — 9 May 2013 8 of 16
NXP Semiconductors
UM10706
PCA9635 demonstration board OM13333
7. OM13333 demonstration board main components
8. PCA9635 evaluation steps
The PCA9635 functions are controlled by WIN-I2CUSB Lite GUI. Refer to the PCA9635
data sheet for additional information on the registers and functionality.
Connect the hardware as described in Section 4 . The PCA9635 demo board address is
set to 0xC4 on switch (S1) as A[0:6] = S1[1:7] = 0100011 (0
→
ON, 1
→
OFF). When you
have correctly installed the software and the demonstration board hardware is connected
and recognized by the computer, start the Win-I2CUSB Lite software. As shown in
Figure 5 , when the demonstration board hardware is correctly connected to the USB port
and the computer recognizes it, the message ‘Hardware Detected’ is displayed on the
bottom of the window.
Switched 3.3 V and 5.0 V power supplies are controlled through the ‘Options’ menu or by
double-clicking the 3.3 V or 5.0 V symbols on the bottom of the window. Power supplies
are disabled by default, and must be enabled before using the I
2
C-bus devices on the
board. I
2
C-bus frequency is controlled through the ‘Options’ menu or by double-clicking on
the frequency symbol on the bottom of the window.
8.1 Color mixing and dimming LEDs
1. From the ‘Device’ drop-down menus, select ‘LED Blinkers and Dimmers’, and from
the subsequent drop-down menu select ‘PCA9635 16-bit LED Driver with 8-bit PWM’
as shown in
Figure 5 .
2. Check the ‘Auto Write On’ box (lower left), uncheck the ‘Low power mode (oscillator
off)’ box to enable the device to ‘Normal mode’ (upper left).
3. The device configuration screen is displayed by clicking the following options:
– ‘PWM 0 to 7’ individual brightness control for LED0 to LED7 as shown in Figure 6 .
– ‘PWM 8 to 15’ individual brightness control for LED8 to LED15 as shown in
Figure 7 .
– ‘Group Control’ for group duty cycle (GRPPWM) and group frequency (GRPFREQ)
control as shown in
Figure 8 . GRPPWM is group PWM for global brightness
control when DMBLNK bit (MODE2 register, Group control = dimming) is
programmed with logic 0, a 190 Hz fixed frequency signal is superimposed with the
Table 1. OM13333 demo board main components
Device Description Address/LED output Location
PCA9635PW 16-channel 8-bit PWM Fm+ I2C-bus
25 mA voltage switch LED driver 0xC4 for I2C demo board 2005-1
interface U1
LW-E67C White LED LED0, LED4, LED8, LED12 D2, D4, D6, D9
LRTB_G6SG RGB LED LED1, LED2, LED3 D3
LRTB_G6SG RGB LED LED5, LED6, LED7 D5
LRTB_G6SG RGB LED LED9, LED10, LED11 D7
LRTB_G6SG RGB LED LED13, LED14, LED15 D8
LTST-C170KGKT PCA9635 power supply either 3.3 V or
5 V indicator Green LED D1