The rail can drive it. No using the 3.3V rail will not cause damage to the processor I/O pins as long as the reset lines is sued to make sure they are not driven until reset is released..
Gerald On Tue, Sep 16, 2014 at 11:25 AM, Ulli <[email protected]> wrote: > > Can the 3V3 supply of the Beagle drive all the components regarding max > current? > Could that blow the beagle like described at the beginning? > > Am Dienstag, 16. September 2014 18:18:25 UTC+2 schrieb Gerald: >> >> It has to be HW or the application and use of the hardware. Maybe you >> have a short or some other issue with your assembly. >> >> Gerald >> >> >> On Tue, Sep 16, 2014 at 11:13 AM, Ulli <[email protected]> wrote: >> >>> @Gerald: What else can be wrong except the hardware design? >>> >>> Am Montag, 15. September 2014 23:25:11 UTC+2 schrieb Ulli: >>> >>>> >>>> I am not sure what you mean with "to disable the buffer before until >>>> you come up". >>>> Directly connect the Beagle SYS_RESETn pin to the pin 29 of the >>>> Atmega`s? >>>> >>>> What would be the positive effect by using the SYS_5V. I think it is >>>> directly connected to the Beagle DC plug. So, it can drive more current? >>>> >>>> Two more ideas: >>>> * would it be helpful to add a 0,1µF capacitor to the beagle voltage >>>> supply pins on the header, between VDD_3v3 and Gnd very close to the beagle >>>> headers? >>>> * would it be better to completely supply my cape from SYS_5V and >>>> create the 3v for the Atmegas and the other components on the cape with the >>>> MCP1703? >>>> >>>> Am Montag, 15. September 2014 23:14:45 UTC+2 schrieb Gerald: >>>>> >>>>> Nothing else jumps out at me. The 5V rail you are using is on before >>>>> the board is powered up, but I don't think that should matter. You could >>>>> switch to SYS_5V, no reason not to.As you only have four wires to the BBB, >>>>> you might try adding some isolation there, and use the RESET signal to >>>>> disable the buffer before until you cone up. >>>>> >>>>> There may be something else in your setup. But, schematic wise >>>>> I don't see anything else. >>>>> >>>>> Gerald >>>>> >>>>> >>>>> On Mon, Sep 15, 2014 at 4:09 PM, <[email protected]> wrote: >>>>> >>>>>> Yes of course. I added this option just to run the cape for first >>>>>> tries on a USB port. >>>>>> >>>>>> Could you find any other problems? I am currently thinking to connect >>>>>> the SYS_RESETn of the BBB directly to the reset pin of the atmega`s? >>>>>> >>>>>> Am Montag, 15. September 2014 23:06:09 UTC+2 schrieb Gerald: >>>>>>> >>>>>>> Looks like you have shorting posts for your standalone versus cape >>>>>>> mode. If you ever by accident plug in the standalone mode into the BBB, >>>>>>> then you will damage the board for sure. >>>>>>> >>>>>>> Gerald >>>>>>> >>>>>>> >>>>>>> On Mon, Sep 15, 2014 at 3:51 PM, ulli <[email protected]> wrote: >>>>>>> >>>>>>>> >>>>>>>> You are right, there must be something wrong but I do not know what. >>>>>>>> I understood that the blocking capacitor is missing. But I do not >>>>>>>> know if that is the only mistake and this is the reason why my beagle >>>>>>>> stopped working because of my cape.... >>>>>>>> >>>>>>>> I updated the circuit to that configuration like it is when I have >>>>>>>> it connected to the beagle. >>>>>>>> https://drive.google.com/file/d/0B8Fq4yYMgG7uTFlIRjdjcGRUYlE/ >>>>>>>> edit?usp=sharing >>>>>>>> >>>>>>>> >>>>>>>> Am Montag, 15. September 2014 22:32:54 UTC+2 schrieb Gerald: >>>>>>>>> >>>>>>>>> So your contention is that this is all correct? Do I read you >>>>>>>>> right? >>>>>>>>> >>>>>>>>> Gerald >>>>>>>>> >>>>>>>>> >>>>>>>>> On Mon, Sep 15, 2014 at 3:24 PM, <[email protected]> wrote: >>>>>>>>> >>>>>>>>>> Thanks for your quick answer and very helpful feedback! >>>>>>>>>> >>>>>>>>>> I am not sure if I understood right. >>>>>>>>>> >>>>>>>>>> Currently I have to options to power the cape. >>>>>>>>>> 1. Use the cape without the Beagle >>>>>>>>>> --> Power supply over the FTDI connector and solder header >>>>>>>>>> Pin2-Pin3 connected on the MCP1703 side. >>>>>>>>>> --> 5V solder header Pin1-Pin2 connected >>>>>>>>>> --> 3,3V will be generated with the MCP1703 from the input >>>>>>>>>> voltage VIN >>>>>>>>>> >>>>>>>>>> 2. Use the cape with the Beagle >>>>>>>>>> --> Power supply all over the beagle headers and solder header >>>>>>>>>> Pin1-Pin2 connected on the MCP1703 side. Therefore no voltages will >>>>>>>>>> be >>>>>>>>>> generated by the cape itself... >>>>>>>>>> --> 5V solder header Pin2-Pin3 connected. 5V from the beagle. >>>>>>>>>> --> 3,3V from the beagle >>>>>>>>>> >>>>>>>>>> Therefore the atmega`s can only power up when the 3.3v supply of >>>>>>>>>> the header is available. >>>>>>>>>> The 5v supply is always on thats right. But 5v is only used for >>>>>>>>>> LED`s and the Piezo Buzzer and this parts are >>>>>>>>>> disconnected with a BC817 from ground. >>>>>>>>>> >>>>>>>>>> Yes all wires which are named as GND are connected. >>>>>>>>>> >>>>>>>>>> Do you really see an issue on that? What needs to be changed? >>>>>>>>>> >>>>>>>>>> Am Montag, 15. September 2014 21:56:47 UTC+2 schrieb Gerald: >>>>>>>>>>> >>>>>>>>>>> Your regulator must be turned off until the VDD_3V3 rail comes >>>>>>>>>>> up. Right now it comes up almost immediately as it is powered from >>>>>>>>>>> either >>>>>>>>>>> the expansion header or a weirdly designed 5V DC input. The idea of >>>>>>>>>>> gating >>>>>>>>>>> the ground to control power will not work as you already have a DC >>>>>>>>>>> path to >>>>>>>>>>> ground, assuming that all of your grounds are connected together as >>>>>>>>>>> they should be. >>>>>>>>>>> >>>>>>>>>>> Gerald >>>>>>>>>>> >>>>>>>>>>> On Mon, Sep 15, 2014 at 2:45 PM, <[email protected]> wrote: >>>>>>>>>>> >>>>>>>>>>>> Oh I understood, I need to add the C1 on each Atmega 3V3 >>>>>>>>>>>> supply. --> blocking >>>>>>>>>>>> <https://dict.leo.org/ende/index_de.html#/search=blocking&searchLoc=0&resultOrder=basic&multiwordShowSingle=on> >>>>>>>>>>>> capacitor >>>>>>>>>>>> <https://dict.leo.org/ende/index_de.html#/search=capacitor&searchLoc=0&resultOrder=basic&multiwordShowSingle=on> >>>>>>>>>>>> But could that really be the issue which stopps the BBB >>>>>>>>>>>> running. I can also not boot the beagle up when I have removed the >>>>>>>>>>>> cape. >>>>>>>>>>>> When I want to boot up the beagle alone the power led flashes >>>>>>>>>>>> up one time...and thats it.... >>>>>>>>>>>> >>>>>>>>>>>> Am Montag, 15. September 2014 21:29:20 UTC+2 schrieb Gerald: >>>>>>>>>>>>> >>>>>>>>>>>>> IC1. Your regulator. >>>>>>>>>>>>> >>>>>>>>>>>>> Gerald >>>>>>>>>>>>> >>>>>>>>>>>>> On Mon, Sep 15, 2014 at 2:17 PM, <[email protected]> >>>>>>>>>>>>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> What do you mean with C1? >>>>>>>>>>>>>> >>>>>>>>>>>>>> Am Montag, 15. September 2014 21:08:59 UTC+2 schrieb Gerald: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Looks like C1 is not gated by the 3.3V rail from the >>>>>>>>>>>>>>> BBB connectors. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> . >>>>>>>>>>>>>>> Gerald >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> On Mon, Sep 15, 2014 at 1:54 PM, <[email protected]> >>>>>>>>>>>>>>> wrote: >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> Hello all, >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> I urgently requesting your support! I am desperate! >>>>>>>>>>>>>>>> I am currently developing a radio cape which has two >>>>>>>>>>>>>>>> Atmega328p, 3xRFM69 radio modules and some other small things >>>>>>>>>>>>>>>> on it. You >>>>>>>>>>>>>>>> can find the circuit in the following link: >>>>>>>>>>>>>>>> https://drive.google.com/file/d/ >>>>>>>>>>>>>>>> 0B8Fq4yYMgG7uQ3k3WkJUbG9icWs/edit?usp=sharing >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> When I use this cape on by BBB, the Beagle stopped working >>>>>>>>>>>>>>>> during operation. I tried to reboot it but it now do not boot >>>>>>>>>>>>>>>> up like the >>>>>>>>>>>>>>>> issue described in the Beagle Wiki as "Improper Power Down". I >>>>>>>>>>>>>>>> never >>>>>>>>>>>>>>>> unplugged the power cord from the board. It just stopped >>>>>>>>>>>>>>>> working. >>>>>>>>>>>>>>>> When the cape is connected to the beagle the components are >>>>>>>>>>>>>>>> sourced by VDD_3V3Exp and VDD_5V. So no external power supply. >>>>>>>>>>>>>>>> I >>>>>>>>>>>>>>>> additionally just have the Uart4/5 connected to my circuit.... >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> I would really appreciate your help. Because I really do >>>>>>>>>>>>>>>> not understand what the matter is! >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> THANKS A LOT! >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> -- >>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> -- >>>>>>>>>>>>>> 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. >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> -- >>>>>>>>>>>> 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. >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> -- >>>>>>>>>> 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. >>>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>> 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. >>>>>>>> >>>>>>> >>>>>>> -- >>>>>> 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. >>>>>> >>>>> >>>>> -- >>> 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. >>> >> >> -- > 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. > -- 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.
