Search the Community

Hi guys, I'm currently in the process of planning a PIC-based capacitive touch device (2D panel, 12cm x 12cm). First and foremost I want to use it via USB but eventually it could communicate via serial connection. So there is a chance it might output data for midibox projects. Wondering what would be the best way of talking to a midibox I had a look at the serial-register-based DOUT modules (e.g. http://ucapps.de/mbhp/mbhp_doutx4_r5.pdf ). So what we have here is an SPI-based communication and a hardware layout for a 2x5 pin header which I could easily use. I'm just having a hard time deciding on what to do with power levels. If no USB power is provided the device could be supplied by the 5V power from the midi box (also made available through the pin header). However, since it's a 3.3V IC a power regulator will have to be used. Easy. But I guess the SPI signal levels from the midibox master will be 5V as well, right? So do you think I'll run into some problems when my 3.3V PIC microcontroller will receive e.g. an SPI clock at 5V? I guess it will always have to send its data (MISO-path) at 3.3V, right? What would be suitable (yet simple!) hardware workarounds to provide a bus interface that is flexible in terms of signal levels?