SenseHat; Random Pattern using FrameBuffer: No Error?

Asked Feb 08 '16 at 18:28

Active Feb 08 '16 at 18:36

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This Raspberry Pi Post talking about the SenseHat gives the following example to fill up the LED matrix with random colours:

cat /dev/urandom > /dev/fb1

This works: but also generates the following error:

cat: write error: File too large

I can use 'dd' instead

dd if=/dev/urandom of=/dev/fb1 count=1 bs=128

This works: and doesn't give an error: but I just got the figure of 128bytes from trial and error - what is the real size to use here ?

[Also: can somebody add 'SenseHat' to the list of tags ; it seems we should have this here?]

edited Feb 08 '16 at 18:36

asked Feb 08 '16 at 18:28

monojohnny

try use sudo before the cat command? – Piotr Kula Feb 08 '16 at 18:49
Thanks - makes no difference - the framebuffer is apparently 128bytes in size; and anything over that will result in the error (same with the dd if I use 'bs=129 count=1'. – monojohnny Feb 08 '16 at 18:54
Sorry it was just a guess. I don't know that much about the frame buffer ;( – Piotr Kula Feb 08 '16 at 18:56

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