Hi. I’m making bike computer with GPS, and everything was going great, until I re solider oled pins. Now one screen shows text from both. I checked connections , and everything looks to be the same as before changes . Im using 0.91 oleds which are connected to tca 9548A i2c splitter. When I connect second oled to first one sda and scl , second one shows text from both, and first show nothing , so it is not oled problems. When I connect this screens to arduino, without tca i2c scanner is stuck at scanning (it doesn’t show “no i2c device “ nor “i2c device found “.
Yes they were on pcb. Both then and now sda from oled 1 is connected to sda 7 on tca, scl oled 1 to scl 7, oled’s 2 sda and scl to 6 sda and scl on tca, and finally Vcc from both displays are connected to each other and to 5v, same with ground, but obviously it is connected to ground
I have come to the same conclusion, but it would be strange, because earlier it was working, and I haven’t changed soldiering to the tca . Thick black cable on the photo is going to pcb with displays .
I did not want to do this, but I think you are right that this is the best way. Thanks for your advice about wire. On that board I was using not solid core wire, and you are right that solid one would be better. There is just one more thing that puzzles me. The thing is, when I checked the connections with a multimeter, I didn't see anything connected that shouldn't be, so i don't thing that it is because of bridges
I managed to solve the problem. Source of the problem was that black cable you can see on 1st and 2nd photo. It has 6 wires inside 0,2mm wide each. They are to thin to handle two screens. Now I must find as thin as possible cable with 6 wires (or 3 cables with 2 wires each ), that can handle that . Thanks for all your support.
You need to be careful running I2C though a cable, there is a lot of capacitive coupling between the wires and I2C has a limit on how much capacitance it can handle. If you use telephone or network cable the wires are usually paired and twisted together, making the problem worse.