grim_reaper
Senior Member
Hello all. I've found a relatively cheap RGB LED, which is labelled as either 'addressable' or 'intelligent' depending on which search results you follow. My preferred supplier has a datasheet which can be found here (PDF).
Now, hopefully most of you will agree with me that this datasheet is somewhat lacking in critical detail, hence the following questions!
If I've interpreted it correctly, the output should be held at half the (LED) supply voltage (we'll use 5V for examples here), and raised/lowered to create the binary data stream. It sounded like a simple method of time-independent driving (or edge-driven I suppose it should be called?) - there don't appear to be any timing requirements aside from keeping the output at 2.5V steady when you want to latch the data. Or do you interpret it differently?
The issue I have now, at the prototype design stage, is how to generate a 2.5V output which can be pulled high and low.
Is it as simple as using a potential divider across the supply to obtain 2.5V, then using a PICAXE pin to drag the line high and low? I'm thinking set the pin as an input for 2.5V, output high for 5V and output low for 0V - but that smells like it needs a diode somewhere (the basics are not my strong point - too many years of using other people's pre-built equipment at work!).
Has anyone seen this kind of driving method somewhere else? I.E. can anyone identify the IC family used inside the LED?
Thanks for any insights - or even better - experience with this very LED
Now, hopefully most of you will agree with me that this datasheet is somewhat lacking in critical detail, hence the following questions!
If I've interpreted it correctly, the output should be held at half the (LED) supply voltage (we'll use 5V for examples here), and raised/lowered to create the binary data stream. It sounded like a simple method of time-independent driving (or edge-driven I suppose it should be called?) - there don't appear to be any timing requirements aside from keeping the output at 2.5V steady when you want to latch the data. Or do you interpret it differently?
The issue I have now, at the prototype design stage, is how to generate a 2.5V output which can be pulled high and low.
Is it as simple as using a potential divider across the supply to obtain 2.5V, then using a PICAXE pin to drag the line high and low? I'm thinking set the pin as an input for 2.5V, output high for 5V and output low for 0V - but that smells like it needs a diode somewhere (the basics are not my strong point - too many years of using other people's pre-built equipment at work!).
Has anyone seen this kind of driving method somewhere else? I.E. can anyone identify the IC family used inside the LED?
Thanks for any insights - or even better - experience with this very LED