Initial Clock Format

rpi-rgb-led-matrix-master/adapter/passive-3/README.md

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+Adapter PCB to support up to 3 panel chains
+===========================================
+
+   * This is a passive board. It is simple, but the logic level will be out of
+     spec for the LED matrix (3.3V vs. 5V) which might or might not work.
+     Driving long cables with the GPIO pins is also not a good idea.
+   * You typically want to consider using the [active board](../active-3).
+   * Works for Matrix up to 1:16 multiplexing (32 rows). For 1:32 multiplexing,
+     you want to use the [active board](../active-3). You can of also hack
+     this board as [suggested in this bugtracker entry](https://github.com/hzeller/rpi-rgb-led-matrix/issues/360#issuecomment-321104348) to make it work with
+     64x64 boards.
+   * Only really advisable, if the LED panels have 74HCT245 (as opposed to just
+     74HC245) in their input stage, because then they can deal properly with
+     the 3.3V logic levels coming from the Pi.
+   * Supports up to three panel chains for newer plus models and
+     Raspberry Pi 2/3 that have 40 GPIO pins.
+   * Open source KiCAD PCB EDA format.
+   * (not very pretty layout, was just lazy and let the auto-router do it).
+   * The FAB files are provided as [passive3-rpi-hub75-adapter-fab.zip](./passive3-rpi-hub75-adapter-fab.zip)
+
+This board is [shared on OSH Park][osh-passive3] (not affiliated).
+
+![Preview][rendering]
+
+[rendering]: ../../img/passive3-pcb.png
+[osh-passive3]: https://oshpark.com/shared_projects/FNAtZUsP