4 ms·
Love the simplicity of the circuit with the daisy-chained uart lines and the use of a time-to-live counter to determine the target so you don't need to give eac
by wzdd 4y ago
Love the simplicity of the circuit with the daisy-chained uart lines and the use of a time-to-live counter to determine the target so you don't need to give each one an ID.
- tiagod 4y agoAnother approach to this, seen in addressable LED strips, is to have two commands - SET and RESET - where the first call to SET after a RESET will change the LED colour, and the next ones will just pass the value to the next node. RESETs will always be passed to the next node, resetting the whole strip. This doesn't require the hop counter.
- RL_Quine 4y agoThe APA102 is probably even simpler, it acts as a 1 byte shift register register per LED and passes the bytes down the chain without needing to really know the total length, there's some special case to latch all the data into the output registers. I'm fond of that design because it needs no timing specific input, you could easily input the data with push buttons if you cared to.
- sowbug 4y agoGE Color Effects G-35 Christmas lights from about a decade ago used a similar scheme, except that they boot up in an "enumerate" state and use the first transmission to each figure out their own unique address (or pass the messages down the line). After that, they can each be addressed individually. (Edit: jgrahamc beat me to it!)