Support for 4 or 8 outputs in multi output mode for Rpi2040

[meltman]

Hello, I have forked and modified HyperSPI for four output support on Rpi2040 (feather scorpio) but would like to see this baked in.

Is this on the radar at all? The changes seem fairly easy in HyperSPI and HyperSerial - just looking for max performance/modularity in builds. My implementation is hacky, and doesnt properly vet second, third, fourth indexes. Seems like taking advantage of the rpi2040 state machine is something that should be reflected even with differential multi segment. Your only penalty is the longest strip. Thoughts?

[awawa-dev]

Hi!

Thanks for sharing this and for the work on the fork!

To be honest, we try to keep HyperSPI as plug-and-play as possible. We’ve noticed that even 2 segments can be confusing for many users to wire and configure and in case of typical TV setups it's usually enough, so adding more might increase the "support surface" significantly. However, we’re interested in the performance gains you mentioned. If we were to merge this, we’d need it to be:

• Dynamic: Not hardcoded to 4, but flexible for 3, 4, or more. From what I recall, the current ESP32 & Pico LED drivers used by HyperSPI can support up to 8 strips without major modifications or a significant increase in memory usage.
• Cross-platform: It shouldn't break the unified workflow for ESP32 users. Contrary to Pico, ESP32 needs have to have GPIO output defined per signal.
• Multisegment was originally designed for cases where both segments are equal. I recall some issues where a shorter second segment in reverse mode could cause memory corruption. If we are to implement this, we need to solve that logic properly once and for all.

Overall it might be a great optional feature for "power users."

[meltman]

I can work the firmware to properly support 2 or 4 segments. Three would be silly I think so it should validate either 2 or 4. For me it works brilliantly but reversing the strips has some issues which I need to troubleshoot further. My build uses four segments with a data line per, 144 count strips with 688 total - you end up with performance of the longest strip size which for me is 220, the others just have to "wait" while that data is rendered out. I'll share a lot more about the build in time plus a bunch of 3d printable items to build a setup with cheap angle aluminum. Cheers to a great project. Looking forward to HyperHDR stable with the infinite color engine!