Do you mean a signal shifter for different supply voltages, or to adapt data signal levels / protocol converter?
In either case, they will have filters and capacitors to cover for power surges (either from the board supply, if wiring is not very good, or when transmitting a lot of data, which can cause spikes if the power supply filter is of a marginal design). The better ones of course have better filters/drivers. With signal interfaces, there is also the question of signal levels (and to a lesser extent current), the standards allow for some tolerance, if your device works very close to the minimum standard, then any deviation (power surge, heat effects, etc.) are more likely to cause problems. Problem meaning that the signal level is out of spec and wrongly interpreted by the device, sending erratic messages, causing the software to freeze. If you have an oscilloscope, you could try to measure and compare against the standard. A crude way could be to just measure with a voltmeter, to see if at least the static signal is within spec. Don't know the input impedance of the IOIO board, but if it drains a good amount of current, then you are running the shifter at its limits (with the better ones having drivers for higher currents). With signals out of spec, a firmware change won't help much, other than maybe prevent a freeze if input data is garbage or the hardware has locked up. -----Original Message----- From: Horst Rupp [mailto:ho...@rupp-family.de] Sent: 22 June 2012 11:11 To: xcsoar-user@lists.sourceforge.net Subject: Re: [Xcsoar-user] IOIO Card Freezing up Hi all, this is a reply to my own post and a call for advice. When soldering up my level shifters, I fortunately did build a couple of them, not only the two needed for the IOIOBox. With a substitute level shifter my freeze-up problem becomes much more rare. Beforehand I had a freeze-up within minutes to 2 hours after starting the communication. Now, with another level shifter, the interval is 8 - 10 hours. These are cheap level shifter, bought on-line for less than 6 Euro. To me this looks like violation of tolerance limits of signals exchanged between level shifters and IOIO board. Unfortunately, I have no equipment to check that. And being more a software than a hardware guy, I am not sure I would find something. However, could that be the reason ? Or is the reason for the freeze-up tied to intolerances of signal treatment in the IOIO board ? Would it be worth while to dig into firmware versioning of the IOIO board (which I would like to avoid) ? Any idea around ? Would be great to hear something. Horst ----- Horst Rupp aka 1R www.how2soar.de -- View this message in context: http://xcsoar.1045713.n5.nabble.com/IOIO-Card-Freezing-up-tp5457507p5709841.html Sent from the xcsoar-user mailing list archive at Nabble.com. ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
