From reading https://learn.sparkfun.com/tutorials/getting-started-with-the-smartled-shield-for-teensy I think I understand how addressing works up to 32x32.
I’m just not too sure how it works when you chain panels after that. There are no address lines to say “this is for panel #0, #1, or #3”.
Thinking about it, I’m guessing the way is to keep pushing more data into the shift registers and it gets pushed onto the other panels? Then, when you select a line, it lights up the line on all the panels based on the data for columns sent through the shift registers to all of them, correct?
The “5th address line” for 64x64 isn’t shown in the pinouts I’ve found. Does it take a redundant ground line and turn it into the extra address line? (maybe pin #4 or #8?)
Either way I understand how you can get 2x as many pixels with an extra address line, but I’m a bit more surprised that 64x64 seemed slower in my tests than 64x32x2 chained (49fps vs 53fps).
If they added a 5th address line, shouldn’t it be twice as fast as 64x32x2 chained?
Is there a limit to how many panels you can chain in theory?
(yes, there is a limit on the microcontroller side on how quickly it can push data and memory required of course). Basically the more panels you have, the longer it takes to load the shift register and push data onto all the other panels. You still get the same /16 refreshes, but you have to start pushing into the shift register faster and faster to keep the same FPS and eventually you hit the wire limit of the shift register assuming your hardware can push data that fast.
No idea what number of panels that translates into though. I’m thinking about big video displays with plenty of panels working together
Has anyone used multiple teensies to drive each panel at higher speed and somehow made a bigger display without chaining but by merging multiple displays each controlled by their own teensy?