It depends on the source current versus the sink current. Whichever one is higher will dictate the direction of the LED, source or sink.
The BBB drive is limited to 4ma to 6mA. I would use the design of the BBB as a reference and use a transistor to drive the LEDs. Cheap. But you can use an open collector device if you link. Open collector is sink current. You can get inverting and non-inverting versions. Gerald . On Mon, Jun 15, 2015 at 8:14 PM, WZ9V <[email protected]> wrote: > Is there a reason a particular reason that the LED examples connect the > current limiting resistor to GND and light the LED with a logic high state > on the pin? > > I'm more used to TTL open collector where the current limiter goes on VCC > and you drive the pin low. Are the GPIO pins on the BBB able to provide > the same current in both states? My digital logic knowledge is somewhat > dated. > > -- > 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. > -- Gerald [email protected] http://beagleboard.org/ -- 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.
