I can only speak from my experience. I have three Adafruit sensor breakouts connected on I2C bus 2. Each of these has its own 10K pull-up resistors. The last board did not work until I added an external 1K pull up. It is 100% reliable since then. I have built this twice and experienced the same thing both times. I spent a lot of time chasing software and asking questions on this forum. Five minutes with an oscilloscope showed me the real problem was that high values on the SDA line were not reaching 3.3V before it was sampled. Based on this, a logical next step is to add an external 1K pull up and see what happens.
> On Jan 25, 2021, at 12:35 PM, Dennis Lee Bieber <dennis.l.bie...@gmail.com> > wrote: > > On Mon, 25 Jan 2021 10:42:50 -0500, in gmane.comp.hardware.beagleboard.user > Steve Lentz <stlentz-re5jqeeqqe8avxtiumw...@public.gmane.org> wrote: > >> Here is the diagram for my i2c device. This shows where the pull-up >> resistors are added. You will need something similar. >> >> But first check the documentation for the thermo-click to see if it already >> has pull-up resistors. It may have 2K, 5K, 10K already. Don’t allow the >> parallel resistance to go below 500 ohms. >> > > If I interpret the confusing schematic from > https://www.mikroe.com/thermo-9-click there appear to already be a pair of > 4.7k pull-ups on the board. > > > -- > Dennis L Bieber > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/e70u0g58r86qs7ct4roe7b5fjpgk6pit1f%404ax.com. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/F621C5DC-2FD4-4100-847E-90E367F84602%40gmail.com.
