Thanks for the heads up on the uno. I am actually using a Moteino that I had on my bench. It is a 3.3v device and uses the uno bootloader. I have a second KX134 board to test now also. I have modified the example wire I2C scanner sketch to just use a fixed address, 0x1F ( I also tried 0x1E for tests). I expanded the error reporting in that sketch to print out all 5 results. On my original KX134 board I get code error code #2, received NACK on transmit of address. This seems to be the same code if I don’t have anything connected to the I2C bus. I have this in a loop, but the newer board locks up right after the wire.endTransmission() instruction. I made some voltage measurements and got different results for each board.
Board 1: CS=3.3V, ADR=3.3V, TRIG=0V INT1=2.8V INT2=2.8V SDA=3.3V SCL=3.3V
Board 2: CS=3.3V ADR=0.966V TRIG=0V INT1=0V INT2=0V SDA=0.2V SCL=3.3V
The pullups seem to be connected on each board when I use an ohm meter on those pads.
I would like to get at least one of them working. I guess I could cut all the onboard pullups, and try external pullups. However, INT 1 and 2 should not be connected and are driven low per the datasheet. So, I am not sure why I have voltage on Board 1. Any suggestions? Have you had issues like this on the KX134 Boards? Thanks