wiki:Lichee Pi Baseboard

Version 3 (modified by pulkomandy, 7 months ago) ( diff )

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Notes

Currently using some random SD image I found on the web. It does not have audio and ethernet. It is from 2017, so the next step is to build a newer one.

Upstream uboot and Linux should work fine.

The LCD videomode is currently configured statically with an uboot build option CONFIG_VIDEO_LCD_MODE. This needs to be tweaked to support VGA output using the LCD IO pins, mainly the hsync needs to be a lot wider than it would be for LCDs (about 20% of the horizontal total according to the VESA GTF, but modern VGA can probably get away with less than that).

TODO: it would be great if this was settable from uboot environment instead of having to rebuild. It is possible to edit it directly in the SD image with a hex editor however, so that's better than nothing.

For doing SCART, the hsync/vsync needs to be turned into a composite sync (that's just a XOR of the two signals). I put a +5V line on the VGA output so I can power a chip doing the XOR in the SCART adapter (and also power DDC lines on VGA displays). I have to check if the LCD driver accepts doing such lowres things.

Various links

Other interesting CPUs

In QFP packages:

  • Allwinner V3lp: new pin compatible (?) version with low voltage RAM
  • Allwinner V3x: new version of the V3s with more RAM (not pin compatible)
  • Allwinner T113: dual core CPU, also has embedded RAM

In BGA:

  • Allwinner D1 for RISC-V fun (sipeed has a system on module for it already)
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