Comments on AD5941 GPIO2 cannot act as general-purpose output — any workaround without a board respin?

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AD5941 GPIO2 cannot act as general-purpose output — any workaround without a board respin?

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I'm using the AD5941 (CPZ-RL7) and driving 3 external mux address lines from its GPIO0, GPIO1, and GPIO2 pins. This IC has only 3 GPIO's. Firmware engineer reported that GPIO2 cannot act as general-purpose output. I also did not check the datasheet in detail while doing the schematic. Now board fabrication and assembly is going on.

Below is the table from the datsheet of AD5941.

Image_alt_text

So GPIO2 can't be toggled as a normal output bit the way GPIO0/GPIO1 can. My board is already built with GPIO2 wired to the MSB of a 3-bit mux address, and I need all 8 address combinations.

Image_alt_text

Has anyone found a way to get GPIO2 to behave as a software-controlled static/toggleable level?

Appreciate any war stories or patterns from anyone who's hit something like this before.

ADC firmware

posted 3 months ago

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War stories... (1 comment)

Lundin‭ wrote 3 months ago

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War stories would be: avoid BGA, QFN and similar packages like the plague, especially during the prototype stage. Everyone makes mistakes, and there is typically no easy way to patch them and save even a prototype. If there is no other option it might be best to start playing with some pre-made eval board before your first prototype spin.

What you could also do is to go through your board release routines. How many engineers reviewed the schematic and layout? (Hint: should be >1) Who gets to say "go"? (Hint: shouldn't be the board designer themselves) Is the BoM within manufacturing budget (do you have one?) when you look at volume purchases? (Since you let a $10 part with no 2nd source onto the board)

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Comments on AD5941 GPIO2 cannot act as general-purpose output — any workaround without a board respin?

AD5941 GPIO2 cannot act as general-purpose output — any workaround without a board respin?

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