Just to confirm this. >From the TPS datasheet:
OFF In OFF mode the PMIC is completely shut down with the exception of a few circuits to monitor the AC, USB, and push-button input. All power rails are turned off and the registers are reset to their default values. The I2C communication interface is turned off. This is the lowest-power mode of operation. To exit OFF mode one of the following wake-up events has to occur: • The push button input is pulled low. • The USB supply is connected (positive edge). • The AC adapter is connected (positive edge). To enter OFF state, set the OFF bit in the STATUS register to ‘1’ and thenpull the PWR_EN pin low. Please note that in normal operation OFF state can only be entered from ACTIVE state. Whenever a fault occurs during operation such as thermal shutdown,power -good fail, under voltage lockout, or PWR_EN pin timeout, all power rails are shut-down and the device goes to OFF state. The device will remain in OFF state until the fault has been removed and a new power-up event has occurred. When the brownout occurs, the unit goes in the "off" state and happily stays there. Apperently, the voltages subject to brownout recovering does not define as a "positive edge". If anyone has a pretty solution for this, I'd be interested. Obviously, I can implement some kind of a watchdog that cuts the 5V altogether at some point but is there a SW or other 'easy' solution? On Tuesday, December 17, 2013 1:35:13 PM UTC+1, James Littlefield wrote: > > As I said in the original post, the bench supply is capable of more than > 3A...far more than the BBB takes. I've duplicated the problem on 2 > difference bench supplies and with multiple BBBs (ie the problem is not > specific to one particular BBB board). > > J- > > > On Friday, December 13, 2013 10:49:07 AM UTC-5, Kees k wrote: >> >> Hey, did you try another power supply? Probably the PS has problem >> supplying the current and drops voltage? Or there is a current limitation. >> >> I tried to reproduce by only connecting P9.5, P9.6 and P9.1 (GND) , but >> could not. >> >> On Tuesday, November 19, 2013 2:00:55 AM UTC+1, James Littlefield wrote: >>> >>> New to BBB but experienced with embedded systems. >>> >>> I'm working on a project using the BBB. Supplying +5V (up to 3A) >>> directly to the pins on P9 from a quality bench supply. I've found that >>> briefly switching the +5V supply OFF and then back on can pretty reliably >>> leave the BBB in an odd state characterized by... >>> a) No LEDs on >>> b) Very little current drawn from supply (10mA or less) >>> c) +5 present on P9.5 and P9.6 >>> d) 0.687V on P9.7 and P9.8 ( should be SYS_5V ). >>> e) P9.9 = 3.57V >>> f) P9.10 = 0V >>> >>> I've found that once the system is in this mode no amount of >>> pressing/holding the momentary BBB pushbuttons will get the system working >>> again. Removing input power, waiting 10 sec or so, then restoring power >>> will get things working again. >>> >>> Has anyone else seen this? It seems sort of like an issue with >>> the TPS65217C chip but I've not found any reported errata on that part. >>> >>> Thanks >>> Jim >>> >>> >>> -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
