I'm using the CardKB peripheral attached to an FPGA. I can't power it with 5V because the inputs to the FPGA are not 5V tolerant, so I am powering it with 3.3V. However, the results that I am getting from the I2C driver ( looked at with a logic analyser) do not reflect the keys pressed, so I am wondering if there is any reason that the device will not work properly when powered with 3.3V. Has anybody tried this?