Karl, The topic starter there reported that a reboot via watchdog didn't work. But the AM335x reference manual <http://www.ti.com/lit/ug/spruh73k/spruh73k.pdf> says that the watchdog can generate a reset pulse, that "causes the PRCM module to generate global WARM reset of the device, which causes the nRESETIN_OUT pin to be driven out of the device" (page 4444). I think it's worth a try once again, and if nRESETIN_OUT is actually driven low, then it will help.
In that thread they also mention PMIC_POWER_EN signal, which can turn off the PMIC. The real-time clock of AM335x can control an external PMIC (TPS65217C on the Beaglebone Black) by means of that signal. If PWR_ENABLE_EN bit of the RTC_PMIC register is set to 1, ALARM2 event can turn the PMIC off, and ALARM event (or ext_wakeup event) can turn the PMIC on. This could probably drive the processor through a power cycle. However, as far as I understand, RTC must be powered by a battery to be able to generate that ALARM event. Another idea: the TPS65217C data sheet <http://www.ti.com/lit/ds/symlink/tps65217.pdf> describes various ways to perform the "power up sequence" (page 18), and it can be done from ACTIVE state too, by setting the SEQUP bit of the SEQ6 register to 1. I'm trying to understand now, whether this can cause a processor power cycle (and thus, drive the nRESETIN_OUT low), because some power rails are not affected by the "power up sequence". What do you think? Regards Alex On Friday, December 12, 2014 11:12:41 AM UTC+1, Karl Karpfen wrote: > > Hi Alex, > > when I understand schematics of BBB correct, this input is hard-wired to > the boards reset line only, so there is no chance to toggle that pin > without a hard reboot of the whole board (means even a simple software > reset of the CPU is not enough). > > Karl > > > 2014-12-12 10:20 GMT+01:00 <[email protected] <javascript:>>: >> >> Karl, >> >> Thank you for the link. So, according to that thread, we cannot start the >> board reliably without modifying the hardware. >> >> But what about doing something with nRESETIN_OUT pin? The datasheet says >> that the pin can be used to reset external devices, although it recommends >> using the pin as input only (page 1149). I wonder whether a special reset >> signal, generated on that pin to reset the transceiver chip, will work or >> not. >> >> Regards >> >> Alex >> >> >> On Thursday, December 11, 2014 12:36:42 PM UTC+1, Karl Karpfen wrote: >>> >>> OK, I found the thread I mentioned: http://e2e.ti.com/ >>> support/arm/sitara_arm/f/791/t/347189 >>> >>> Am Donnerstag, 11. Dezember 2014 12:34:10 UTC+1 schrieb Karl Karpfen: >>>> >>>> I remember a thread in TI's forum stating that this issue can't be >>>> resolved by software. There is a hardware problem with the PHY which >>>> requires either a power cycle or a reset of PHY. And for BBB the reset >>>> line >>>> isn ot connected. To solve this issue via software a connection from one >>>> GPO to this reset line would be required. >>>> >>>> Try to find this thread after TI has changed its webboard-software, >>>> things are way more complicated there... >>>> >>>>> >>>>>>> >>> >> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "BeagleBoard" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/beagleboard/9mctrG26Mc8/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected] <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > -- 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.
