I also have a problem with PCA9634. It involves GLOBAL DIMMING. I am driving a Simple 7 seg LED and I would like all segments at the same brightness I set the Global dimming to 0x7F. MODE1 and MODE2 are 0x00 and I set LEDOUT0 and LEDOUT1 to be my pattern for Each Character. I wrote a 11 to the Segments I wanted on. very little OVERHEAD, It should involve writing only three Registers and the LEDOUT can be written one after the other.
Again GLOBAL DIMMING may not work, It works fine with LED0 - LED7 Dimming.
The Way I am setting the BITS in LEDOUT is to set the Segment I want on to be 1 1.
From the Manual, I set LDRx to allow BOTH CHANNEL DIMMING and GROUP DIMMING
When all PWM registers for Each Channel are ZERO and ONLY GRPPWM has a VALUE THE LEDS stay off.
As an experiment, I left GRPPWM at 0x7F and I wrote 0x7F to EVERY PWM0 - PWM7 register and the LEDs work.
What I am under the Impression of, that GROUP PWM does not seem to work on this chip. And because it does not work my debug time was greatly extended.
