topic pca9634 in Other NXP Products

pca9634

marius_haeffner — Tue, 08 Jan 2019 14:55:16 GMT

Hello,

I have a problem with NXP´s LED driver pca9634 and its I2C communication. (datasheet).

For setup and programming I followed the instructions of the datasheet.

SETUP

i2c master µC: ATMEGA32U4 (datasheet).
The PCA9634 is the only bus slave so i chose the address 0x01 (A0=HIGH and A1..A6 connected to gnd).
bus speed: 100kHz
pull up resistors: 4k7 (Vdd = 5V)
LED resistors 430 ohms / I = 11mA

The schematic is attached.

PROBLEM

The PCA9634 works fine for a while (about 10 minutes) then it stucks at the current state (blinking, permanent on/off).

Analyzing the signals with an oscilloscope shows:

SDA = 5V
SCL = 1V constant.

After power off/on reset the chip does not work anymore at all!

Furthermore I used another µC as master (SAMat03463 --> datasheet) and in a third scenario an i2c-USB emulator.

I always have the same result as described.

Does anybody has an advice for this issue or had a similar behavior?

I`m very grateful for every response.

Best regards,

Marius

Re: pca9634

guoweisun — Wed, 09 Jan 2019 02:36:00 GMT

Can you give the complete schematic for analysis?

Re: pca9634

marius_haeffner — Thu, 10 Jan 2019 08:09:33 GMT

Hi,

I updated my question and attached the complete schematic

Re: pca9634

guoweisun — Fri, 11 Jan 2019 00:52:00 GMT

Hi Marius

Could you please show your complete schematic file of PDF format?

Re: pca9634

Spiffy_Guy — Fri, 23 Feb 2024 01:17:44 GMT

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.