UM10572
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1 — 7 June 2012
9 of 16
NXP Semiconductors
UM10572
PCA9955 demonstration board OM13330
–
‘Other’ GRPPWM is group PWM for global brightness control, GRPFREQ is group
frequency for global blinking control when group control = blinking in Mode 2
register, PWMALL is brightness control for all LED outputs, OFFSET is control LED
output delay offset, IREFALL is control output current for all LEDs as shown in
Figure 10
.
4. Click the ‘LEDOUT’ configuration screen and select ‘PWMn & GRPPWM’ for LED[1:3]
(see
Figure 8
).
5. Click the ‘Output Gain’ configuration screen and adjust the IREF[1:3] = 0x30 for
LED[1:3] output current at 3.8 mA = 48
×
80
µ
A (see
Figure 9
).
6. Click the ‘PWM 0 to 7’ configuration screen and move the PWM1 (red) PWM2 (green)
PMW3 (blue) bars for color mixing (see
Figure 6
).
7. Once you set a color on D3 RGB LED with the PWM[1:3] values, click the ‘Other’
configuration screen and move the GRPPWM bar for dimming effect (see
Figure 10
).
Fig 5.
Drop-down menu selections