If you apply power to an I/O pin without power on the power rails of the processor, that is basically what you are doing!
Read the datasheet for the processor and look at the power sequencing required by the designers of the processor. http://www.ti.com/product/am3358 Gerald On Mon, Feb 24, 2014 at 12:11 PM, <[email protected]> wrote: > Gerald Coley <[email protected]> wrote: > > [-- text/plain, encoding quoted-printable, charset: ISO-8859-1, 56 lines > --] > > > > Not really. The idea of powering a chip via an I/O pin will > > always cause damage. It means voltage as specified by the datasheet of > > the component. > > > I don't aim to 'power' it via the I/O pin! Maybe that's your way of > saying it but it's a very odd way. The likelihood is that there will > be a biggish resistor in series with the input to limit current and > there will probably also be some clamping diodes or maybe a buffer > amplifier but whatever you do there *cannot* be 'no voltage'. > > What I'm asking really is what will be tolerated with no problems, > every chip spec I have ever seen specifies some sort of minimum, not > zero. > > So what is the "voltage as specified by the datasheet of > the component."? That's what I'm asking really, I'll go and look at > the processor spec sheet. > > > > It is your choice, but, it will cause damage to the part. > > > > If you power a system form one power source, it is not hard to do. Using > > two power sources that are not synchronized with each other, that is > where > > the issue comes into play. > > > Real systems don't come like that! Are you going to turn off every > single thing in you car/boat/house etc. just so you can power down a > Beaglebone monitor? > > -- > Chris Green > ยท > > -- > 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/groups/opt_out. > -- 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/groups/opt_out.
