Resistors are fine. But, if you don't take them off correctly, you may never get them back on, assuming that is a desired feature.
Diodes have voltage drops. Depending on what you use, the 3.3V would be come 2.7V. Also, you need to make sure none of the lines from the other boardd are powered up before the BBB processor is powered up. Gerald On Fri, Oct 4, 2013 at 10:12 AM, garyamort <[email protected]> wrote: > I've mulling about an really off the wall idea, and I'm wondering if there > is a standard way to do this. > > I want a "cape" which can be used to connect a BeagleBoneBlack with > another dev board in a manner to maximize flexibility. > > IE P8 pins 1 to 45 will connect to 45 pins on the other board, with the > assumption that > P8-1 and P8-2 will both connect to GROUND on the other board > > 3 to 45 will be used in GPIO mode on both boards and both boards are using > the same voltage levels. > > > However, since they are 2 dev boards, it's always possible that the > hobbyist will want to use the pins differently. For example, he might want > to attach an LCD to the Bone, using pins P8 28-45 in LCD mode. And he > doesn't want those signals being sent to the other dev board. > > Using larger parts, one could use dip switches or jumpers inline with the > connection. But that adds bulky parts to the board. > > What I'm thinking is that I could use a very low value SMD resistor for > each line - with the expectation that if the hobbyist wishes to disconnect > a line they will remove the SMD resistor. It's not as flexible as a jumper > - but it allows for the end user relatively easily disable some links if > they need to. > > Similarly, both boards provide some voltage rails for powering attached > chips. For example, P9-3 and P9-4 provides 3V Those power rails should > not connect from one board to the other in expected usage. However, it's > possible that the end user would prefer to use the 3V rails provided by the > bone for everything. As such, would it be appropriate to place 2 SMD > diodes on that line in opposition, with the expectation that the end user > would remove one of those diodes and replace it with a small resistor if > they want to use it? > > IE: P9-3 ---- 3V SMD Diode---><--- 3V SMD Diode---Other Boards 3v Rail > > The 2 diodes would block each other in "normal" operation, giving the > hacker the flexibility to switch usage if they want. > > > I'm assuming in my ignorance I am missing some more obvious solution/type > of part to use to configure this. > > -- > 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.
