What is the technical reason why Interstate75 can only drive up to 256x64?

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I am trying to get a lot of Hub75 panels driven. I have therefore purchased several Interstate75W Picos.
I wonder why I can’t connect more than four 64x64 panels to one Pico. Is it a timing issue, a memory issue, or something else about how the panels work?

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Well - it turns out that it can drive more panels, at least with the C code. I connected 6 in row and created a Hub75 instance with 384 by 64 px, and it just worked - I can access every pixel in it. The only problem is that I’m slowly running out of RAM with the other things I want to do on the Pico …

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@ThomasT was this possible in Python land? or did you have to move to C?

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Just a FYI post. The latest RP2350 version has more memory.

  • Powered by RP2350A (Dual Arm Cortex M33 running at up to 150MHz with 520KB of SRAM)
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I did that in plain C where I had more control over memory.

Also: I’ve since moved to using a Raspi 5, which can drive 24 panels, see Looking for fun interactive ideas for a 320x240 LED display - rpi-rgb-led-matrix

I used this code: GitHub - hzeller/rpi-rgb-led-matrix: Controlling up to three chains of 64x64, 32x32, 16x32 or similar RGB LED displays using Raspberry Pi GPIO

And drivers: Anyone tried the Joy-it MATRIXCTRL as an active adapter? - rpi-rgb-led-matrix

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I know some Python, but not enough to add my own equivalent to DISPLAY_INTERSTATE75_128X64…

I hear you on the RAM, but then again trying to display a 1MB ics calendar was never that smart to begin with 😅