7 Replies Latest reply on Mar 23, 2015 9:05 AM by DaKn_263916

    Fried cy8ckit-505

              I seem to have fried he PSOC 5 on my new development board, which I've had for a week or two now. I'm not sure what I did, but I can't connect to it anymore, and the firmware that I had installed isn't doing anything anymore. Also, when I plug in my device to the USB port, I'm getting "Unknown USB Device (Device Descriptor Request Failed)". Any ideas? Or am I out $100?   
        • 1. Re: Fried cy8ckit-505

          Although it is a sad reason, wellcome in the forum!


          When you are sure that you haven't done something really wrong to the board I'd suggest you to compain at the deliverer of the kit.


          Could save you some money.





          • 2. Re: Fried cy8ckit-505

            Do you have at least some idea what you did that might have caused this? Shorted something? Too high or reversed voltages? Did you power the board externally? What have you connected as external components?


            Regarding USB: do you use the correct USB connector? There are two on the -050, and you need to use the one for the programmer.


            Otherwise: I think its unlikely that both the programmer and the target PSoC are fried, except for a too high Vdd.


            Does the Power LED light up (D5)? There test points for the Vddio voltages, are they at the right voltages? Power jumper still set to the right voltage? Is the analog supply voltage at least as high as the digitial supply voltage (thats a bad trap)?

            • 3. Re: Fried cy8ckit-505

              It was working very well and I was making progress with my design and firmware. So the problem isn't with connectors or jumpers.




              The board stopped working when I tried to hook it up to a stepper driver, so it almost certainly died as a result of something I did. My theory is that one of the jumpers accidentally touched a pin on the stepper driver board (I noticed it was sitting right next to some of the pins on the board). The steppers are being driven by 12V. So it's very possible it got briefly connected to 12V by accident.




              The DVKProg5 programmer section of the boad is showing up in Device Manager sometimes. At other times I just get an unrecognized USB device. When it is recognized and I select the debug target, the programmer shows up, but not the PSOC 5. And yes, D5 is on. So I think I fried the PSOC with a voltage too high on the input of one of the pins.




              I tried moving the two power jumpers, J10 and J11 to the 5V position (I had them in 3.3V). If J10 is in the 5V position (regardless of the position of J11), LED3 and LED4 both light up. But the PSOC 5 still doesn't show up. However, if J10 is in the 3.3V position (regardless of J11), both LED2 and LED4 are off.




              If I've only fried the PSOC 5, it seems I might be able to replace that chip. Do you think that would work? I have a rework station.




              I'll have to be a lot more careful next time.






                -- John

              • 4. Re: Fried cy8ckit-505

                12V would definitely fry the part, any I/O pin or supply pin.


                Its possible that just an I/O pin got fried, and rest of chip


                still good. But sure sounds like part replacement would


                be in order. I would look at the power supplies to make sure


                none of the regulators or protection diodes got fried as well.




                Also, in general, if you are motor driving large transients are


                always present. So make sure no pin thru external feedback


                from H Bridge or power MOSFETs gets yanked outside any rail


                by ~ .5V or more, that is a recipie for latchup and parasitic diode


                burnout. DSOs can be set up to trigger easily on both high and


                low transients, single shot trigger.




                How are you interfacing steppers to PSOC ?








                http://www.cypress.com/?rID=39677     AN57821 - PSoC® 3, PSoC 4, and PSoC 5LP Mixed Signal Circuit Board Layout Considerations


                http://www.cypress.com/?rID=40247     AN58827 - PSoC® 3 and PSoC 5LP Internal Analog Routing Considerations


                http://www.cypress.com/?rID=39974     AN58304 - PSoC® 3 and PSoC 5LP – Pin Selection for Analog Designs






                Regards, Dana.

                • 5. Re: Fried cy8ckit-505

                  I think the hole chip is fried as I looked at the voltages in different places and they didn't seem out of line. Plus the PSOC 5 doesn't show up in the list of devices that can be programmed with the programmer.




                  I was using a RAMPS board (http://reprap.org/wiki/RAMPS_1.4), which has Alegra A4998 stepper drivers. And at the time I was testing it, I had an oscilliscope attached to the stepper outputs rather than a motor. So I think what happened is that I accidentally touched one of the jumpers to a pin on the Pololu board (carrier board for the A4998) that had 12V. But that's just a theory.




                  -- John

                  • 6. Re: Fried cy8ckit-505

                    Rule of thumbs: power off when changing the cabling. Its true when working on mains voltage, but even 12V can be dangerous (if not for you, then for the components).


                    So yes this seems like it might fry both chips. And if you are unlucky, it even might fry the USB port on your computer (if it was connected at that time). When the USB connection is flaky this might be the reason.


                    But there might be something else: you say that when jumpering to 5V the LEDs light up. That could mean that just the 3.3V regulator is damaged. Since the programmer on the board is powered by 3.3V all the time, this could explain why its flaky. So check the voltages. (and look at the schematics in the user guide for details)


                    Also note when playing around with the voltage settings to never ever have the digial voltage (J10) higher than the analog voltage (J11). It will fry the chip.

                    • 7. Re: Fried cy8ckit-505

                      From the datasheet -




                      17. The power supplies can be brought up in any sequence however once stable Vdda must be greater than or equal to all other supplies.




                      Regards, Dana.