Hello,

I am using the MBED to communicate to an ADC I have on a board. I am using PuTTY to output the results. This system has worked flawlessly for months on the computers at work.

But now, I am trying to run some experiments in another room on my laptop, and for whatever reason, the MBED cannot seem to communicate with the ADC when connected to my laptop.

PuTTY is still communicating with the MBED and outputting text prior to the I2C communication, but it just cannot get past this point. I tried again on my work computer and still it works fine, but no luck with the laptop. The only change in setup is which computer the USB is plugged in to.

Any ideas why this is happening? Thanks.

Could be a GND or powersupply problem.

Is the ADC getting power?

Are the mbed and ADC connected to the same GND. Note that I2C needs three connections between the master and slave: SDA, SCL and GND.

Also make sure that you have pull-up resistors to 3V3 on the SDA and SCL lines. The mbed IC2 master code will hang without the pull-ups.

My laptop was running off battery, so I think the grounding issue was the issue. Thanks!