Posts: 1
Joined: Wed Oct 11, 2017 11:46 pm

Using camera without GPU

Thu Jun 14, 2018 5:15 pm

Hi, I'm not sure if this is the right place to post this question but I am working on a project that will use the GPU for time sensitive IR communications over GPIO on headless pi Zeros. This decision was made to prevent the pi's Linux scheduler from interfering with IR data flow since it requires reliable and accurate timing on the level of 100-200 μs. However the project may eventually be used to take stills via a pi cam. My question is if the camera module requires GPU access for simply saving stills? If so, will saving a still consume enough QPUs to interfere with timing of an IR emitter and an IR receiver?


Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 21333
Joined: Sat Jul 30, 2011 7:41 pm

Re: Using camera without GPU

Fri Jun 15, 2018 8:11 am

Possibly. There is a LOT of SDRAM traffic when a still is captured, so that might have some effect as the CSI peripheral requires the bus, so the ARM side may slow down a tiny bit. 100us? Probably not.

There are other interactions that might cause problems as well, but difficult to assess.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
"My grief counseller just died, luckily, he was so good, I didn't care."

Return to “Bare metal, Assembly language”