7 Replies Latest reply on Nov 5, 2014 2:07 PM by onehorse

    Edison module - voltage outputs question

    rubidium

      I'm starting to design a simple board to interface with the Edison module. It will be like the mini-breakout, but a lot simpler and smaller - more like the Edison module in size and with just a LiPo charger and USB OTG connector. This question has to deal with my requirement to provide 5v to the external USB device I would want to connect to this board in my application. Do I need to add a boost converter to supply the 5v or is it available as an output of the Edison module?  Although I don't see the availability of 5v at any of the 70 pins in the Hirose connector, Intel's hardware guide does mention that the internal power management IC (PMIC) includes a 5 V 1.2 A boost converter among other things.  Am I correct in assuming that this 5v never makes it outside of the module, or am I missing something? Where is 5v/1A used?

      Jim

        • 1. Re: Edison module - voltage outputs question
          faceplant

          There is no +5V output from the Edison.  Are you planning on supporting USB host (or OTG) on this board?  If not, then you don't need/want to provide +5V to the USB connector.  If you do plan on supporting USB host (or OTG), then you do need a boost converter and a switch (for USB OTG).  I believe the Edison will control the switch to turn on/off power to the OTG connector.

          • 2. Re: Edison module - voltage outputs question
            rubidium

            Yes I will need the 5v as a USB host.  Presently, using the mini-breakout, I have to insert a powered hub to get things to work.  No problem for me to add a small boost converter chip, an inductor and a few resistors to my board.  I've determined that I only need about 50mA.  I guess I remain curious as to what the 5v/1A segment of the PMIC is there for.  I wish the documentation were better.

            Jim

            • 3. Re: Edison module - voltage outputs question
              onehorse

              We also have a small adapter board and are using the D+/D- USB port for peripheral interfacing. One problem we had was we had to make sure the USB ID was pulled to GND in order to put the Edison in host mode.

              • 4. Re: Edison module - voltage outputs question
                faceplant

                That should be an internal connection in a USB OTG cable.  That's the way that the Edison can tell if you are wanting it to act as a USB client (normal USB cable) or a USB host (USB OTG cable).  The connectors are the same, but the OTG cable connects the ID line to ground.

                • 5. Re: Edison module - voltage outputs question
                  onehorse

                  We're not using a USB cable, only the native D+/D- and power outputs, so the grounding of the USB ID pin must be done on the adapter board (or by soldering to the adjacent GND pin!).

                  • 6. Re: Edison module - voltage outputs question
                    rubidium

                    For my project, I plan to have a male Mini-B SMD plug on my board so that the resulting little package (Edison module, my board, small 500mAhr LiPo) plugs directly into it's intended destination (digital SLR) without a cable. Therefore, I'll have to GND the ID pin on the board - or perhaps in the interest of versatility have a pair of solder pads on my board that can be bridged/unbridged. During my development, I'm using an OTG adapter cable now into the mini-breakout, and then a powered hub into that, and then the camera into the hub. Works beautifully, but the next step is to simplify and downsize.  I think that in the end I can have an overall package dimension of 30mm x 45mm x 16-17mm.

                    Jim

                    • 7. Re: Edison module - voltage outputs question
                      onehorse

                      Yes, we did this except we just soldered the power and D+/D- wires directly to breakout pads on the adapter board; no extra USB connector. If i were to add a USB connector to our adapter board I would put in some logic to detect/toggle the USB ID from host to device mode so it could also be programmed or stream serial output. Of course, the Edison can do all these things via wifi so it is really not necessary!