64x32 Mod8 C-Stacking Issue

I bought 20 of the newern64x32 P4 panels. They were advertised as 1/16 scan, but after trying them, I discovered they were really 1/8 scan. Of course, Louis had just added support for them last week (Thanks Louis!).

I have several arranged in a 128x64 C-Staked array (2 horizontal rows of 2 64x32 panels). I have the daisy chain loop top row-right to top-left, down to bottom-left to bottom-right. This worked on my 64x64 panel project.

I’m set up using:
kMatrixWidth = 128;
kMatrixHeight = 64;

The issue I have is that all the two bottom panel update like they are still MOD16 scanned. In other words, the bottom panels draws rows 0 to 7 at 8-15 & rows 16 to 23 at 24 to32 then go back & draw rows 8 to 15 at 0 to 7 & rows 24 to 31 at 16 to 23. The top rows (which are not upside down) work fine.

If I configure for a linear arrangement by commenting out the SMARTMATRIX_OPTIONS_C_SHAPE_STACKING option, the panels work just fine, all draw from top to bottom.

What am I missing? Is it because the panels aren’t square?

Unfortunately MultiRowRefreshMapping and C-shaped stacking are incompatible. It would require rewriting a lot of delicate code to make it compatible.

I just added this to the MultiRowRefreshMapping section in the Wiki (it was already in Features):

Note: SM_HUB75_OPTIONS_C_SHAPE_STACKING isn’t compatible with panels that require the Multi Row Refresh Mapping feature

You could maybe mount the panels at a right angle to make the same shape but have shorter Z-shaped cable runs, and rotate the matrix in setup

Wow, thanks for the quick reply. How can I tell which panels require MultiRowRefreshMapping ? I guess I thought most did.

No, most panels don’t require it and I didn’t even add it to SmartMatrix Library until ~5 years in. There’s details here:

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