Hello everyone,
I'm facing an issue with a circuit using the PCA9698BGG to control a relay through a ULN2003A. The PCA9698BGG is configured to control outputs IO0_0 to IO0_7, specifically IO0_6, which drives the input of the ULN2003A to activate the relay.

The problem is that IO0_6 is not generating any signal, even when the button is pressed, whereas in another functional box, the relay responds as expected. The SDA and SCL lines are functional and show proper oscillations (verified with an oscilloscope), and the PCA9698 power supply is correct. I have also confirmed that the OE line is properly connected to GND, and the pull-up resistors on SDA and SCL are in place (4.7 kΩ).

Other pins IO0_0 to IO0_7 seem to be inactive, and no response is observed on IO0_6, preventing the relay from being activated.

Has anyone encountered a similar issue, or can you suggest additional steps to check on the hardware side?

Thanks in advance for your help!

 

Bonjour.
This is a website in English only. Post in English, svp.

 

Do you have a solder short V81 pins 7-8?

 

Since device defaults to inputs on power-up/reset and need to be programmed as outputs, my first guess is that you are not programming the PCA9698 properly.
BTW, what is value for VN?

 

Is R22 connected to VDD properly? The top side seems to be either disconnected or extra wire segment. If this schematic has gone to artwork and fab, the top side of R22 may be floating and SDA not pulled-up and device not being programmed properly.

 

Avez-vous un court-circuit de soudure sur les broches 7-8 du V81 ?
[/CITATION]
No

 

Since device defaults to inputs on power-up/reset and need to be programmed as outputs, my first guess is that you are not programming the PCA9698 properly.
BTW, what is value for VN?

the device already programmed.
The value for VN 5v.

 

Is R22 connected to VDD properly? The top side seems to be either disconnected or extra wire segment. If this schematic has gone to artwork and fab, the top side of R22 may be floating and SDA not pulled-up and device not being programmed properly.

Thank you for your response!

I’ve checked R22, and it is properly connected to VDD. The circuit was working perfectly fine before, but this issue appeared suddenly. I have other boxes with the same PCB, and they are functioning correctly. I’ve also compared the behavior of this problematic box with a functional one, and the difference is that IO0_6 (and other outputs) do not respond in the problematic box, even though SDA and SCL lines show proper oscillations.

Do you think it could be a hardware degradation issue, or should I focus on rechecking specific connections or components?

 

the device already programmed.
The value for VN 5v.

From the datasheet I see no mention of non-volatile operation. In other words device must be programmed on power-up and retains its configuration only when power applied. On power-up all pins default to inputs (which is what you are seeing). Suspect you are not programming correctly.
Now, since you say other EXACT SAME boards work correctly with same PCB and software, something is impacting the programming. Will need to look more closely at SCL/SDA signals.
And finally, may be bad part and if you have verified all voltage levels at pins and signal quality on SCL/SDA you will have to try replacing the part.

 

Are the other control inputs functioning correctly?? That is not mentioned. It could be an oprn connection on the "common" side of the circuit.

 

Are the other control inputs functioning correctly?? That is not mentioned. It could be an oprn connection on the "common" side of the circuit.

I would like to know how to get an output on IO0_6 to control I7 of V81. Could you please provide guidance or clarify the steps?
FYI: the V21 is connected to PCA9600 V11.

 

From the datasheet I see no mention of non-volatile operation. In other words device must be programmed on power-up and retains its configuration only when power applied. On power-up all pins default to inputs (which is what you are seeing). Suspect you are not programming correctly.
Now, since you say other EXACT SAME boards work correctly with same PCB and software, something is impacting the programming. Will need to look more closely at SCL/SDA signals.
And finally, may be bad part and if you have verified all voltage levels at pins and signal quality on SCL/SDA you will have to try replacing the part.

I would like to know how to get an output on IO0_6 to control I7 of V81. Could you please provide guidance or clarify the steps?
FYI: the V21 is connected to PCA9600 V11.

 

Repeating the same request each time is not the way to gain any response.

 

I would like to know how to get an output on IO0_6 to control I7 of V81. Could you please provide guidance or clarify the steps?
FYI: the V21 is connected to PCA9600 V11.

Its all in the datasheet on how to use SCL/SDA interface to initialize (program is not really the correct term) the PCA9600. Way too much to describe.
I thought you said the board was already built multiple times and that the processor software already working to initialize the device. You might need to use o-scope to verify SCL/SDA signals. You race them on the scope and verify that the 1's and 0's in the bit stream perform the correct function.