Configuring PCA9624 to blink LEDs

[seanbzd]

If this is not a right forum, please let me know and I'll try to move it appropriately.

Hi I'm using NXP's PCA9624 with a Cypress PSoC 5LP. I have configured the PCA9624 to blink an LED but doesn't work. I can light up the LEDs but can't seem to be able to blink them. Does anyone have any ideas.

According to the datasheet, I've done the following:

1) Write '0' to MODE1 register address 0x00h to configure in normal mode.

2) Write '0x25' to MODE2 register address 0x01h(to write to the DMBLNK) for group controlling the LEDs for dimming and blinking.(I only care about blinking)

3)Write value of  01010111(binary) or 0x57h to LEDOUT0 register at 0x0Ch to blink only LED0 but leave LED1-3 ON.

4)Write value of 0x80 to GRPPWM at address 0x0Ah.

5)Write value of 0x80 to GRPFREQ at address 0x0Bh.

After this i was expecting the LED0 to blink and LED1-3 to stay fully on. I've looked at the data sheet for other possible reasons but can't seem to figure out what the problem is. Please note that I'm able to light up the LEDs solid by writing 0x55 in step 3) and not doing steps 2, 4 and 5. Appreciate any help and suggestions.

[TomasVaverka · Accepted solution]

Hi Sean,

It is necessary to set the individual brightness control for PWM0 (the default = 0x00 is 0% duty cycle, LED output off).

When DMBLNK bit is programmed with logic 1, GRPPWM and GRPFREQ registers define a global blinking pattern, where GRPFREQ contains the blinking period (from 24 Hz to 10.73 s) and GRPPWM the duty cycle (ON/OFF ratio in %).

Best regards,

Tomas

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