Arduino Due. How to remove built in I2C pullup resistors?

Hi there,
I am having issues with I2C using standard SDA (Pin20) / SCL(Pin21). I've read a lot about I2C and Arduino Due and learned, that the twp lines are internally pulled up by 2x1k5 resistors.

I also read that the pullup's are too strong and some issues are resolved when these resistors are replaced by say 4k7 or higher values and I want to give this a try.

I also located the resistors on the board. Actually it consists of a register network 4x1k5. But these thing is so incredible tiny!!

Any suggestions how I can do it without damaging my Due board?

What is a"register network"?

You do not need to remove those resistor networks. Just put the 4.7K resistors in parallel. The resultant pullup resistance is about 4.5K which is fine.

What I2C parts are you adding? Do those parts have pullups on them? Many modules do come with pullups installed. If adding several such boards, it is easy for the total parallel pullup resistance to become to low (or strong).

What issues are you experiencing?

No sorry! 1k5//4k7 results 1.14k total resistance

Please describe those issues. Be sure to post links to any I2C modules that are associated with the problem.

Why do you think the pullups are the problem?

A resistor network is when several resistors are in one single package. Here, on Arduino Due it's 4 resistor each 1k5

Do you have a soldering iron?

Just read it in several independent forum posts

Just read it in several independent forum posts

That is not useful information. Please describe YOUR problem. See the "How to get the best out of the forum" for posting instructions.

Ah, ok, so not a "register network" - I thought maybe it was something to do with internal architecture of the Due.

Yes but it's too tiny to do it. If there's no better way I'll do it using a cutter

You are right.
I corrected my post. I am not used to the xKx notation so made a mistake. I reverted to the x.xK notation that I know.

Cutting is the most dangerous way. Stick with the iron. Apply the iron and some solder, push gently sideways, it will slide off. Usually, it will stick to the iron, which is also handy.

But have you checked, what all four resistors do?

Yes, I have. 2 are unused and 2 are used as pullup's for SDA, SCL repectively. So removing the whole package will do no harm as long as I really can safely remove it.

The trick with the soldering iron is to heat all 8 pins simultaneously and that seems to get very tricky, doesn't it?

That's what the solder blob does. Convey heat to all pads. Some heat will also go through the component as well, but you are throwing it away (I assume).

OK, I'll give it a try. Wish me luck :slight_smile:

Practice on some junk boards.

Hahah, It might be that I have at least one junk board in a few minutes :rofl:

Exercise "Due" diligence.

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