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Bare Metal image capture

Posted: Wed Jul 18, 2012 12:14 pm
by steve_gulick
Hello - I'm interested in being able to capture images in a bare metal program as soon as possible after power on. Does anyone have an idea of the latency before the first frame would to accessible to the arm side?
Thanks

Re: Bare Metal image capture

Posted: Wed Jul 18, 2012 2:30 pm
by Cycl0ne
HI,

can you give more information? From where you want to take the capture? You are on baremetal = no graphics activated. so you activate the graphics card -> you get a framebuffer -> you can draw on it -> you can take a capture of it.

Re: Bare Metal image capture

Posted: Wed Jul 18, 2012 2:46 pm
by steve_gulick
Hi Cycl0ne

No, I mean capturing images from the future 5MP camera via the GPU. I want to power up the raspberry pi based on an external trigger then start capturing images to memory and/or sd card with minimum delay

Thanks

Re: Bare Metal image capture

Posted: Wed Jul 18, 2012 3:07 pm
by DexOS
First you need a way for bare metal OS to access the future 5MP camera, so that depends on what info is released.
But i would say at a guess about two seconds.

Re: Bare Metal image capture

Posted: Thu Jul 19, 2012 2:24 am
by steve_gulick
I was hoping it would be more on the order of 200ms. Maybe there might be some tricks that could speed up the GPU's booting?

Re: Bare Metal image capture

Posted: Thu Jul 19, 2012 8:14 am
by Cycl0ne
Dont think so, the ARASAN(?) MMC Controller needs atleast 1sec for initialisation.

Re: Bare Metal image capture

Posted: Thu Jul 19, 2012 12:35 pm
by DexOS
steve_gulick wrote:I was hoping it would be more on the order of 200ms. Maybe there might be some tricks that could speed up the GPU's booting?
From boot you will not get that, but you could get that easy if you leave it running, but in a type of sleep mode.