ReimuNotMoe edited a comment on issue #2988: URL: https://github.com/apache/incubator-nuttx/issues/2988#issuecomment-798922955
> Hi @ReimuNotMoe what device are you trying to dump? Do you have a Logic Analyzer to see the bus? Even a "cheaper" logic analyzer can do the trick: https://acassis.wordpress.com/2015/07/19/sigrok-and-a-cheap-saleae-clone-can-save-your-life-i-meant-your-time/ > This way you can compare the i2ctool command from NuttX against STM32 HAL and the Raspberry Pi i2ctool. I bought a DSLogic Plus logic analyzer and used it to inspect the i2c lines. It seems that there are only a bunch of STARTs and STOPs and there are no actual data transfers when running `i2c dump -b 1 -a <addr> 256`, with different devices.  i2ctool output when dumping an EPSON RTC, all 0xff:  i2ctool output when dumping a MCP23017 I/O expander, garbled data:  ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
