TCA9539: TCA9539

Arabella Zhang

Part Number: TCA9539

Tool/software:

Dears,

My customer encountered the following problem when using the TCA9539 chip. Please help me take a look:
In the figure, port 1, port 2, and port 3 are the three IO ports of the 9539 extended GPIO; when port 2 and port 3 change from high level to low level, it will affect the high level of port 1;

Thanks,

Arabella

10 months ago

0 Tyler Townsend 10 months ago

TI__Mastermind 46888 points

Hi Arabella,

Do you have a schematic available for review? Are there any floating input pins on the IO expander?

Regards,

TYler

0 Arabella Zhang 9 months ago in reply to Tyler Townsend

TI__Intellectual 2860 points

Hi TYler,

Thanks for reply.

1.Please see the customer's schematic in the attachment. Please check if there is any problem.

2.Yes, there are IO port control or input without components, there will be floating, reserved function

Many thanks,

Arabella

9539——Schematic.pdf

0 Tyler Townsend 9 months ago in reply to Arabella Zhang

TI__Mastermind 46888 points

Hi Arabella,

Is port 1 floating? It could be possible that port 2 / 3 changing voltage could cause port 1 to change state due to floating pin?

If this is not the case, please show the I2C SDA & SCL for the frame that is being written to cause this issue. I want to see which of the registers are being written to in the output port register.

Regards,

Tyler

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TCA9539: TCA9539