Power issue

[dlmorgan999]

I am working on an LED project using the DigiX.  I have a total of 260 LPD8806 LEDs.  I'm using an external 5V 10A power supply.  I have a cable coming from the power supply that feeds both the 5V and ground lines on the 4-pin cable to the LEDs, and also feeds the DigiX via the VIN and GND pins right next to pin 54 (SPCK1).

Here is the issue.  If I connect the external power, I get odd behavior on the LED string - not all LEDs light, and the patterns don't change as expected (as a point of information, these LEDs use hardware SPI and I'm connecting to pins 75 and 76 for that).  The moment I connect a USB cable to my laptop though (in addition to the external power that is already connected), everything starts working just fine.

Can anyone help?

[dlmorgan999]

In researching this further, my suspicion is that with an external 5V regulated power supply, I should be using one of the pin marked 5V (3 pins away from what I'm using now).   The image on the Kickstarter page labels that pin as "3.4-5.5V Input or 5V Out".

That is a bit confusing to me (how can a pin be either input or output voltage?).  I'm guessing the VIN pin I'm using goes through the onboard regulator, and it's probably not happy with < 6V, but I'd still like to hear confirmation from someone before I make any changes.

[digistump]

Yes a 5V supply should be fed into the 5V pin (and ground to ground) - your just bypassing the 5V regulator then