It is 1 to 2 multiplexing. Meaning, 8 columns are on at a time instead of all 16. I was using 1 to 16 multiplex, then tried 1 to 8 multiplex and it was just too dim. Increasing the voltage would get it slightly bit brighter, but nowhere near the normal brightness of the LED itself. Plus the current started to avalanche if I turned the LED voltage up too much, without getting any brighter.
So, I had to settle with 1 to 2, and set the CAT4016 to 100mA output, with 1 to 2 thats 50Ma per LED, which they are rated for 70. that gives me slightly under normal brightness, but still bright enough plus allowing the LED to last longer.
the RS-485 is 1-way only. There isnt enough time I dont think for 2-way communications. the master board is blasting out packets for 21 tiles, each with its own unique address. Then it sends out a broadcast frame-switch command.
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