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DB25 Switch/LED Connector

MagicFire

May 01, 2007 02:08

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We're new. Sorry if this question has already been asked.

BrightSign HD600 documentation says "Connect LED outputs to the LED CATHODE and connect LED ANODE to ground." Schematic on next page shows the opposite (and what would be reasonably expected).

Which is correct?

Also, "...output is capable of sourcing or sinking up to 24ma at 3.3v..." are LED outputs truly either active high (source) or low (sink)? If so, how do you specify which you want? If not, which are they, sink or source?

Thanks,

Paul

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2 comments

• 0
  
  RokuLyndon May 01, 2007 05:16

  
  
  I'm checking on this, and will get back to you soon.
  
• 0
  
  RokuLyndon May 02, 2007 00:59

  
  
  1. The documentation will be corrected. It should say:
  
  "Connect LED outputs to the LED ANODE and connect LED CATHODE to ground."  
  
  
  
  
  
  2. The output is capable of sourcing or syncing 24mA. In other words, the hardware can support either active high or active low, meaning they can be either sinks or sources of current. The software treats them as active high.  The software doesn't allow you to specify them as active low, so you must invert your program logic if you want them to be connected to an active low output.  
  
  
  
  For a sourcing example, you would connect a LED with the LED ANODE connected to the LED output, and the LED CATHODE connected to ground. In this case, the output is sourcing current, and you will set the output to 1 to turn the LED on.
  
  
  
  For a sinking example, you would connect a LED with the LED ANODE connected to the 3.3V and the LED CATHODE connected to the LED output. In this case, the output is sinking current, and you will set the output to 0 to turn the LED on.  In this case, your program has to invert its logic and set the output to 0 to turn on the output if you are using it as a sinking output.