bigclive Posted February 21, 2019 Share Posted February 21, 2019 Has the WS2815B addressable LED been out for long? I was trying to work out what the extra backup data pin is for, and it appears to be a system where each chip can monitor the data input to the previous chip and if it doesn't get the data passed on from the previous chips output it deduces that the previous pixel may be dead and just continues as normal with receiving the data on its backup pin and sending the stream on from its data out pin as normal. Quite clever really since normally a dead WS2812B style LED would result in the loss of the rest of that entire line. Link to comment Share on other sites More sharing options...
patrick_keys Posted February 21, 2019 Share Posted February 21, 2019 The DI (Data In) pin receives data from the previous device's DO (Data Out) pin as normal. If the device detects a problem with the data received on the DI pin (i.e. the previous device has failed), it automatically switches to receive data on the BI (Backup In) pin instead. This should be connected in parallel with the DI pin of the previous device. The device is smart enough to know that if it is receiving data via the BI pin, it will need to ignore the first 24 bits of data received on that pin to account for the previous failed device. More information here. Link to comment Share on other sites More sharing options...
timsabre Posted February 21, 2019 Share Posted February 21, 2019 That's interesting, hadn't seen them. Presumably that means a 4-wire connection between sections of tape if you want to use the backup - since it's always the LEDs on the ends of sections which get zapped. 12V PSU as well which will help with the dreaded volt drop. The data sheet seems to suggest however that the pixel data signal also needs to be 12V which sounds unlikely to me - VDD=12V, VHigh=0.7VDD, VLow=0.3VDD. Will have to get some and test. Link to comment Share on other sites More sharing options...
musht Posted February 21, 2019 Share Posted February 21, 2019 World Semi is WSWS2811 IC chip for driving LEDs, sometimes found on 12V pixel tape driving 3 LEDS per `pixel`.WS2812 5050 LED with built in 2811 5V supply single data line, 3 wireWS2813 5V supply with back up data line, 4 wire WS2815 12V supply, 5V data. LEDs internally in series across the 12V with a fet to short them out. 4 wire GS, Genesis Semi and SK, Shenzhen Color(?) variants from other makers about. Be aware that some versions of the GS chip enter on board `fun` programs on loss of data... Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.