Re: GTA02 is now an expensive brick / pcf50633 defaults
Andy Green wrote: There's two interesting ideas from Mike though, one is that disable USB insert as ON will help by giving longer for VB_SYS to charge and the other is leave charger enabled. For both of these, they are defeated (USB insert is ON action, charger disabled) by NOPOWER and we have no control then. I'm not considering the NOPOWER case, because as you point out there is nothing that can be done in software to help with that problem. Another software workaround for this issue is to never let the main battery drain into the cutoff state. The PMU can generate a low-battery interrupt. If the FR gets this interrupt, it can re-program the PMU with safe settings and then immediately power off the main device and the Calypso. The battery will still drain a bit from leakage current and self-discharge, but at a much slower rate. That's the simple version - more work is needed to handle cases like hot-swapping batteries while the device is plugged into external power (which could also generate a low-battery signal). There should also be an opportunity for userspace to do a clean shutdown of the device when the battery gets low, but before it reaches the critically-low level to trigger an immediate shutdown. I have not looked at any recent kernels or u-boots (for several months) to see if this has already been implemented. It's somewhere on my to-do list. ___ support mailing list support@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/support
Re: GTA02 is now an expensive brick / pcf50633 defaults
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Somebody in the thread at some point said: | | Mike Montour wrote: | If you program the PCF50633 as: | - charger enabled | - 100mA current limit | - do not wake on USB insertion (avoids the brownout issue) | | then it will have the behaviour that you want - even with a | completely-dead battery, you can plug it in and it will slow-charge the | battery in hardware. I think it still technically violates one of the | USB standards by drawing current without talking to the host, but IMHO | it's unlikely to cause any real-world problems. | | | 1. This really ought to be default behaviour, the current way is really | *really* bad. | | 2. Why stick to 100mA? I thought the USB standard was for ports to support | 500mA? | | 3. I'm sure the FR doesn't need to negotiate with its charger. | | 4. How easy is it to make this change? The issue is more complicated than this. pcf50633 has more than one level of hardcoded default actions, some registers get reset when you tell it to enter what it calls standby but we would more naturally call off, and more get reset again when the small backup battery that is also present on GTA02 becomes exhausted, called NOPOWER state. The real default settings for our variant that occur with NOPOWER forces the charger disabled. So if you stick your FR in a drawer, the main battery is exhausted, the backup battery goes down a day or whatever later, nothing that we did in previous session about charger status sticks, the charger is off. In addition, due to VB_SYS issue, we can't get easily get to the point of running any code on A5 to enable it without a loan from the battery to get us started. Sometimes the battery is in cutoff and does have some power in the cell, it's just disconnected from the terminals. That's when any kind of external kick will get us out of the hole. There is no violation of USB standards if you only pull 100mA, but another default set by going off even is that we pull 500mA from the USB host until the CPU can get started, and that is in violation. But since we can do nothing about it, and we didn't find a host that cares yet, it's OK. There's two interesting ideas from Mike though, one is that disable USB insert as ON will help by giving longer for VB_SYS to charge and the other is leave charger enabled. For both of these, they are defeated (USB insert is ON action, charger disabled) by NOPOWER and we have no control then. If the backup battery had not decayed, it could help, but it only has very partial impact and is not magically delivering the behaviour you want, GTA02 with this issue still will not start if left long enough for backup battery to fall below the pcf50633 threshold for NOPOWER. - -Andy -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkljdhIACgkQOjLpvpq7dMpvDgCfSK+d1rosyd0cJIrP2dcIvkgz yD0An1KMoTi57Z2oxRp0/8RrITsoPSF0 =LB9S -END PGP SIGNATURE- ___ support mailing list support@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/support
Re: GTA02 is now an expensive brick / pcf50633 defaults
Andy Green wrote: There's two interesting ideas from Mike though, one is that disable USB insert as ON will help by giving longer for VB_SYS to charge and the other is leave charger enabled. For both of these, they are defeated (USB insert is ON action, charger disabled) by NOPOWER and we have no control then. If the backup battery had not decayed, it could help, but it only has very partial impact and is not magically delivering the behaviour you want, GTA02 with this issue still will not start if left long enough for backup battery to fall below the pcf50633 threshold for NOPOWER. So are you saying there's no way to reprogram the freerunner to be able to charge from a (completely) depleted battery? ___ support mailing list support@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/support
Re: GTA02 is now an expensive brick / pcf50633 defaults
bburdette wrote: Andy Green wrote: There's two interesting ideas from Mike though, one is that disable USB insert as ON will help by giving longer for VB_SYS to charge and the other is leave charger enabled. For both of these, they are defeated (USB insert is ON action, charger disabled) by NOPOWER and we have no control then. If the backup battery had not decayed, it could help, but it only has very partial impact and is not magically delivering the behaviour you want, GTA02 with this issue still will not start if left long enough for backup battery to fall below the pcf50633 threshold for NOPOWER. So are you saying there's no way to reprogram the freerunner to be able to charge from a (completely) depleted battery? That would seem to be the case. That it can charge when there's enough power to start booting, or it can trickle-charge when off (maybe, with some software modification) but that when it's been off for a couple of days you're out of luck. BIG. DESIGN. FLAW. -- View this message in context: http://n2.nabble.com/GTA02-is-now-an-expensive-brick-tp2109541p2120169.html Sent from the Openmoko Support mailing list archive at Nabble.com. ___ support mailing list support@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/support
