So I’ve been posting on the forums a few times now and then looking for guidance on hooking up 60 MAX7219s in a daisy chain configuration. After trying many things, I finally followed CrossRoad’s initial advice and put some buffers in the chain for the SPI clock signal. Every 6 chips I’d insert the buffer. This worked great for the first ~24 chips. Once I reached 30 chips and onward, I started to notice that the chips after the last buffer wouldn’t work until another set of 6 chips+buffer was connected after it.
I now have all 60 chips hooked up with buffers, and the last 6 chips don’t work. I’ve verified that ICs, power, and buffer for the last 6 chips are working properly, and that the problem is not due to the clock rate. It’s just that they are at the far tail end of the SPI chain that they aren’t working, and I can’t figure out why. Anybody have any ideas what’s wrong? Keep in mind only the CLK signal is passed through each buffer. The only thing I can think of is that it may be reflection of some sort?