I agree! Gerald
On Fri, Oct 4, 2013 at 11:00 AM, Jonathan Smith <[email protected]>wrote: > Lattice use to produce, and I believe it is still available, a product > called ispGDX, ispGDX2 allows one to reprogram I/O's any to any, as well as > adjust input/output threshholds. Something like that would be great for > what your describing. > > Jonathan > > > On Fri, Oct 4, 2013 at 9:16 AM, Gerald Coley <[email protected]>wrote: > >> 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. >> > > -- > 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.
