I2C problems with 2 devices

Projects Networking, Protocols, and Devices
1

Hi there

I have a Arduino Nano project with 2 I2C devices. First, a 16x2 display and a compass.

The I2C wires from the compass are soldered to the display, from where the wires go to the Nano, via a pull ups on both lines. Unfortunately I only had 10K resistors for the pull ups. I know, the values are very high (I would have used 4.7Ks), but I had nothing around over 620 ohms except for the 10Ks. The wires from the Nano, to the "end" on the compass are about 10" long.

If I desolder the compass, I can communicate with the display without any problems. If the compass is connected, there appear mistakes. The display seems to work, but there are characters missing or replaced with other characters. So please note, a good part is correct, but not everything.

What do you think, where should I look for mistakes? Could it be the high pull up value?

2

Could it be the high pull up value?

It would cost you less than a dollar to find out.

3

Have you tried reducing the clock speed? Either that or lower value resistors.

here are someinteresting comments on the topic (at least to me.)

4

PaulS:
It would cost you less than a dollar to find out.

Thanks. I know, but it takes a long time till I have the components. So I wanted to know if there is something to do until I have the parts.

5

is something to do until I have the parts.

Assuming you have more 10K resistors simply put another one in parallel with the first, that will give you 5K which is so close it makes no odds.
Even better put it at the other end of the like to where your pull up is now.