I just recently made some changes to my 1.4 firmware to support Man-in-the-Middle modification of ATR because some device apparently changes the Vcc to 1.8v after reading the ATR that indicates the card supports Class C. I don't have access to the device that exhibit this behavior so I was using a USB Smartcard reader to test it, and my Oscilloscope capture shows that the PC was using 5v vddio mode. The SIMtrace 1 are 5v tolerant, and the last time I looked at Cstartup.asm I believe we set the internal pull-ups to disabled, which is "safe" according to the Atmel part documentation. So long as 5v IO levels are not "on"/"fed" into the PIO lines while the device is in reset, this is probably not an issue for SIMtrace 1 boards.
> From: Mychaela Falconia <[email protected]> > To: [email protected] > Cc: > Bcc: > Date: Tue, 25 Oct 2022 20:03:23 -0800 > Subject: My progress with 5V SIM investigation > Hello SIMtrace community, > > I mentioned earlier on this list, and also in last week's OsmoDevCall, > that I play with some old phones that *may* be putting out 5V toward > the SIM, which SIMtrace2 hw does not tolerate - 5V exceeds the absolute > maximum rating spec of SAM3S chip. > > As the first step in the investigation, I cobbled together a simple > PCB design for a purely passive adapter that connects a SIM socket to > FPC cables from current Sysmocom SIMtrace kits, plus 2.54 mm headers > on both sides of the SIM socket providing convenient probing access to > all signals. This trivial design can be found in my fc-small-hw Hg > repository: > > https://www.freecalypso.org/hg/fc-small-hw/ > > Look in the sim-fpc-pasv directory inside the Hg repo. I haven't sent > this little PCB out to fab yet, but I plan on doing so when my budget > allows it, hopefully no later than a week from now. When I get this > adapter board fabbed and assembled, I will test it with my current > collection of old phones (Ericsson I888, Nokia 5190 and 6190) and see > if any of these phones put out 5V toward the SIM. > > Nokia 5190 and 6190 are powered by 3-cell NiMH batteries, but they > still might put out 5V toward the SIM if they include a charge pump or > some other boost converter. At least in TI chipset history, prior to > our well-known Calypso+Iota chipset, their previous ABB chip Nausica > (used in the legendary TSM30, apparently) could put out either 3V or > 5V toward the SIM, selection under fw control, while powered by a > 3-cell NiMH or 1-cell Li-ion battery, doing some kind of boost > conversion for 5V. (I never found a datasheet for that ancient ABB, > so I don't know the full details.) It will be interesting to know > what Nokia 5190 and 6190 do in this regard. It will also be > interesting to see what Ericsson I888 puts out: it is an older, > higher-voltage beast, powered by a 4-cell NiMH battery, and if the > designers felt like operating the SIM in "5V" or Class A mode, they > could have used raw battery voltage without conversion, as the spec is > 4.5 V minimum IIRC. > > During last week's OsmoDevCall Kevin said that he had some SIMtrace1 > boards with ARM7S, which the datasheet says is 5V-tolerant, and I > recall him saying that he could send me one. To Kevin: I greatly > appreciate your offer, and I may indeed take you up on it in another > few weeks - but let me build my sim-fpc-pasv adapter first, and see > what voltages are actually put out by phones in my collection. > > Now the really interesting phone would be Nokia 2190 - supposedly one > of the very first PCS1900 band GSM phones sold in USA, from around > 1995. That one is powered by a 5-cell NiMH battery and thus seems > very likely to put out 5V toward the SIM, possibly always, without > ever switching down to 3V. I don't have one to test, aside from a > sealed box which I am reluctant to cut open (told it may be worth > a fortune some day, the usual story), but another person on Reddit > says that these phones are very finicky in terms of which SIMs they > accept. I sent him a few of my FCSIM1 cards, equivalent to > sysmoSIM-GR2, a pure GSM 11.11 SIM without any UICC at all, very > old-fashioned, and my contact tells me that Nokia 2190 rejects these > SIMs too! It was my desire to use SIMtrace to see what's happening > with that finicky 2190 that prompted my investigation into 5V > tolerance - and when I get my sim-fpc-pasv adapter built, I will get > back in touch with my Nokia 2190 contact person from Reddit and see > how he would like to proceed. > > M~ > _______________________________________________ > simtrace mailing list -- [email protected] > To unsubscribe send an email to [email protected]
