On Thu 16 March 2017 13:19:25 H. Nikolaus Schaller wrote: > Hi Andreas, > > > Am 16.03.2017 um 12:20 schrieb Andreas Kemnade <[email protected]>: > > > > Hallo Nikolaus, > > > > On Tue, 14 Mar 2017 21:24:18 +0100 > > > > H. Nikolaus Schaller <[email protected]> wrote: > >> Hi all, > >> you may be wondering how progress is. > >> > >> First of all, I have currently 11 GTA04A5 working boards on my > >> desk (one did work initially but failed since now) which boot > >> fine. > >> > >> It turned out that our hw-test script was not testing all > >> components as good as possible, so I have worked on it to > >> be much better. Now it also tests WLAN, Bluetooth, GPS > >> and some other components. In total it was much more effort > >> to put into kernel and hw-test to really be able to do > >> such an automated test. Reason is that you also have to test > >> the tester... And make the kernel and user-space work stable > >> for almost all chips and interfaces. > > > > What I am wondering about is the backup battery test. I do not think it > > is a good idea to test only once. My old semi-broken gta04 gives flaky > > values there. So sometimes the voltage might look ok, sometimes wrong. > > So the test might miss problems. > > Yes. It is very difficult to write tests that have 100% coverage of > all potential failures. Especially for rare failures. > > Most of the tests are a little primitive and hence incomplete. They > mainly test if the PCB has been soldered properly, i.e. if peripheral > components can be accessed and respond reasonable to all stimuli. > > Sometimes they don't even check this. For example the tvout test does > not test hardware (unless a tv set is connected to the headset jack > and somebody has a look at the result). So it is not even an automatic > test. > > The backup test only checks if the supercap is being charged and has > reached a reasonable voltage since power-on. If the supercap would be > missing or had a bad solder joint it would no charge at all. > > It does not even attempt to test the capacity of the supercap and if > and how long it maintains RTC during battery switching.
That's probably a problem here: even an unsoldered polyacene cap would leave the charger circuit with a - however minimal - capacity vs GND, so it would charge up very quickly and for sure reach nominal voltage. For a way more thorough test, the charger circuit in TWL4030 should get switched off prior to voltage test (if possible, I don't have the TRM at hand, with the register specs) or alternatively RTC get checked if it has a "power failed" flag set, or keeps time, after brief removal of main power supply cheers jOERG -- () ascii ribbon campaign /\ against html e-mail - against proprietary attachments http://www.georgedillon.com/web/html_email_is_evil.shtml http://www.nonhtmlmail.org/campaign.html http://www.georgedillon.com/web/html_email_is_evil_still.shtml http://www.gerstbach.at/2004/ascii/ (German)
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