Hi, I accidentally hit reply instead of reply-all, my apologies for making this thread rather hard to read...
Werner Almesberner wrote: > > Thomas Seiler wrote: > > Currently there is not safe / easy way to get power inside the > > Freerunner for 3rd party mods :( > > You mean to make the Neo provide power to external components ? > How about hooking them up to the battery terminals ? They're > reasonably easy to access. Yes. I can imagine people developing some interesting hardware add-ons for their freerunners, *if* there is a proper / official way to power them. Ideally, it would be streamlined enough for commercial add ons, not only DIY. > Alternatively, how about VDD_3V3 on the WLAN test pad ? It's connected > to IO_3V3 through a bead that's rated at 300mA. Or VCCA, which goes > directly to IO_3V3. > > The test points may be hidden. See > http://wiki.openmoko.org/wiki/Image:Gta02a5_pcba_ps.JPG > > > > The temporary fix would be to solder wires on capacitors, but this is > > obviously not a good idea... > > Hah, done it a million times ;-) > > > The current debug connector still has a few not connected (not > > documented?) pins. > > There the undocumented ones should all be unused. That's 21 of them. > > I'm not sure if I'd like to see more things getting added to the > debug connector or whether I'd rather have them on that new test > point connector. The reason is that I'm thinking of ways how we > could get rid of the debug board (but not its functionality). If > this succeeds, then the whole debug connector would go. Well, just thinking out loud here: What about putting a FTDI in every GTA03 and use a mechanical switch, accessible from the battery compartiment, that is switching miniUSB between Samsung SoC and the FTDI, which would only be powered, when the switch is in the right position ? + no debug board anymore, as all phones include the debug function by default + Software upgrading the NOR flash gets easy for everybody - additional cost of switch and FTDI :( - its not possible to JTAG-debug usb drivers, as the miniUSB port is already taken then :( But i diverge... > Of course, there's also a different approach: don't add a new > connector and fill up the debug connector first. Just for > monitoring the power rails I would have a dozen lines, though. > If we add your four audio signals and toss in a pair of GPIOs, we're > already with only 3 lines left. Ah, and I want all the buttons too, > so that's one left, maybe zero. > > Yet another approach would be to put all the things that are useful > for testing on a new connector (which could even be removed in mass > production versions), and put things that are useful for extending > the device on the debug connector. That would mean that we'd never > completely get rid of the debug connector. > > The common denominator would be the FPC that gives access to things > without the overhead of the debug board. > > > [speaking of the lack of power on the debug connector] > > I think it would be possible to wire a few of them [pins] in parallel to > > provide a useful current. > > Hmm, only if you need *very* little power. They're rated at 1mA. > I don't know at what point they really burn up, but almost anything > you could connect would already be about order of magnitude outside > the specification, easily by two orders of magnitude. ok, its a bad idea then. > > In my dreams :-), the debug connector of GTA03 would provide: > > 1) vbatt with a current limiter (always on) to allow for wake sources > > on the 3rd party mod flex... (i.e. rfid readers :-) > > I think making VBAT accessible should be no problem (with the > constraints below). I think some people would bark if I started > to suggest additional circuits for that, though :) straight VBAT is better anyway, it would even allow for a LED torchlight mod. > > 2) io_3v3 that goes to standby together with the freerunner, for > > simpler things like i2c sensors > > Hmm, GTA02 has an unused LDO, but I think we might use them all up > on GTA03 :-( In any case, I would just put that one on a big > test pad (e.g., something like the larger ones around the debug > connector), so that one can easily attach some wire. The FPC > connectors just aren't made for this sort of things. > > I am actually thinking of putting power lines on the test point > connector, but that would be only for monitoring, not to actually > drive something. > > > 3) add one interruptable gpio. > > We might be running low on these. But if there's one that's still > available, definitely yes. > > > 4) put on the unused line in / line out of the wolfson if there are > > still pins left... > > LINE1/2 are on TP3001 and TP3002, but they're pretty hard to access > (right next to the codec). I'm not sure what kind of noise might get > coupled into LINE inputs, though. Outputs are low impedance, so they > should be suitable for the debug connector. The Line in was tought to allow for FM-Radio mod. If you simply set the gain to 0 in the mixer shouldn't this take care of the noice when nothing is conected ? > > 3) use a board 2 board connector (i.e. from molex) to pass higher > > currents) instead of another FPC > > > Hmm, two problems: first, this sounds as if it's getting a bit > expensive. I think an FPC like the one I described should cost > about USD 3-5 a piece, consumer price. (Disclaimer: that's just > from looking at catalog prices of mass-produced FPCs. Could be > that this being a custom design changes the price dramatically.) > I think a piece of PCB with a real connector might end up being > considerably more expensive. > > Second, board-to-board connections are rigid. So you have to make > a much greater effort to stabilize your construction. With the FPC, > you just tape your contraption down and you're good. > > > 6) add all the usb signals ? (including the ID pin) > > That might be an option for GTA03, where we'll probably still have > only Full Speed. After that, we'll almost certainly get High Speed > (finally !), and I'm not sure how this fits with signal integrity > demands. Even Full Speed is somewhat picky. > > All this would allow for battery covers with an fpc circuit to extend the > > functionallity > Hmm, besides power, an FPC should be very suitable for this as > well. Just the "neck" would have to be a little longer than what >I've drawn. (That ~1cm was really just a random guess. It should > be reasonably short, particularly if we want to measure things.) > > > Advantages: > > - can provide useful amounts of power to mods > > Power is still tricky, yes. A big pad would solve the problem for > DIY circuits, because you wouldn't mind a little bit of soldering > anyway, but if you want to make more streamlined extensions, that > wouldn't be acceptable. > > I wish there was a miniature equivalent for the ubiquitous 0.1" > header. Hm, good point. what about the type of header found on a 2.5" Harddrive? (is it 0.05" ?) These should not cost too much, and be still rather easy to get and solder for DIY. You would just need a 2x3 block or so: VBAT VIO_3v3 (power these cannot pe but on FPC) GND GND I2C I2C (these are nice because a single connector for most basic mods is sufficient) Sorry again for messing up the thread... Cheers, Thomas -- Excercise 17: If the human brain was simple enough for us to understand we'd be so simple we couldn't understand. Prove this by induction. _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
