Differences

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--- projects:q3kled [2015/12/16 17:37] – created q3k
+++ projects:q3kled [2018/04/11 21:16] – q3k
@@ Line 1: / Line 1: @@
+{{template>:template:project
+ | name=q3kled
+ | status=[[http://led.waw.hackerspace.pl/\|active]]
+ | founder=[[user>q3k]]
+ | repo=[[github>q3k/ledvideo]]
+}}
 ====== Chinese 'HUB75' RGB LED Driver ======
-[[people:q3k:start|q3k]]'s project to create a Zynq-based RGB LED Matrix driver. In progress!
+[[people:q3k:start|q3k]]'s project to create a Zynq-based RGB LED Matrix driver.
+[[https://youtu.be/gnT0wj1DyD0|Video of a 128x128 panel it action at 32c3]].
+===== Overview =====
+This project targets the [[projects:zturn-hackers|MYiR ZTurn board]] with a custom buffer interface board (to be released). The programmable logic exposes a 65-kbyte block RAM to Linux running on the PS via a full-speed AXI slave. The logic also loads data from the BRAM, gamma corrects it and outputs it to the RGB panel interface.
+===== Current Status =====
+It works! But really needs to be re-written. Keep poking q3k on IRC until he does so.
+Issues:
+  * <del>Vertical glitches</del> Fixed by switching buffers to 5V
+  * <del>Low framerate</del> Fixed by switching buffers to 5V and increasing pixel clock
+  * Horizontal ghosting
+  * No double buffering in hardware
+  * No vsync / interrupts
+  * No runtime configuration
+  * Kernel framebuffer access from userspace (FBDev/DirectFB) locks up whole system
+  * Gamma correction is poor, needs and actual ICC color profile correction
+  * Hardcoded parameters in kernel/mpv driver
+Note: photo of display was taken before dank memes started becoming appropriated by hate groups.
+{{https://owncloud.hackerspace.pl/index.php/apps/files_sharing/ajax/publicpreview.php?x=1278&y=1358&a=true&file=IMG_20151222_185742.jpg&t=vcbwcUxqmTVcCfh&scalingup=0&.png?600}}
+{{https://owncloud.hackerspace.pl/index.php/apps/files_sharing/ajax/publicpreview.php?x=1278&y=1358&a=true&file=IMG_20151222_212052.jpg&t=naEYL6o4nBA6RJR&scalingup=0&.png?600}}
 ===== Components =====
-  * [[https://github.com/q3k/ledvideo|AXI4 Stream IP Core]]
+  * [[https://github.com/q3k/ledvideo|AXI4 slave IP Core]]
-  * [[https://github.com/q3k/q3kled|Linux Kernel driver]]
+  * [[https://github.com/q3k/q3kled|Linux Kernel framebuffer driver]]
+  * [[https://github.com/q3k/mpv|mpv fork with direct LED output (bypassing kernel)]]