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by ACouCam
Sat Mar 04, 2017 5:55 pm
Forum: Advanced users
Topic: PI3 acoustic emissions
Replies: 0
Views: 450

PI3 acoustic emissions

Hi all, We have a project involving the Pi3 as a recording device for some digital microphones. One side-effect of using the Pi that we noticed is that the electronics itself generate very weak audible and ultrasound. The sound seems to differ in frequency and intensity depending on the load on the ...
by ACouCam
Wed Dec 17, 2014 6:41 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI driver latency and a possible solution
Replies: 242
Views: 152996

Re: SPI driver latency and a possible solution

Ok tkanks a lot, didn't know about rpi-source.

Jonas
by ACouCam
Tue Dec 16, 2014 7:55 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI driver latency and a possible solution
Replies: 242
Views: 152996

Re: SPI driver latency and a possible solution

Hi Notro!

Just a question about including this driver in the kernel. Will you try again some time in the future (perhaps when the issue is fixed) and why was the case closed last time?
I would be very happy to see that this would get included.

Regards,
Jonas
by ACouCam
Fri Dec 12, 2014 4:08 pm
Forum: Advanced users
Topic: Disable_L2cache - No boot
Replies: 8
Views: 2601

Re: Disable_L2cache - No boot

Ok, thanks for your reply. Have to try that sometime with more time at hand. It would indeed be interesting to know what caused the effect but of course not 100% relevant to the project. But as I side note we always run apt-get update/upgrade after each rpi-update so probably the changes are quite r...
by ACouCam
Fri Dec 12, 2014 3:27 pm
Forum: Advanced users
Topic: Disable_L2cache - No boot
Replies: 8
Views: 2601

Re: Disable_L2cache - No boot

Hi! We tried to rollback to the last kernel we had installed 3.12.33+. But the same behavior did still occur (higher FPS and higher CPU load). Could it just be that something was not installed properly earlier, causing to the CPU to stall for short amount of times and that would now result in the hi...
by ACouCam
Fri Dec 12, 2014 9:31 am
Forum: Advanced users
Topic: Disable_L2cache - No boot
Replies: 8
Views: 2601

Re: Disable_L2cache - No boot

Well this doesn't seem so relevant anymore. Just updated to the new kernel 3.12.34+ from a max. 3 weeks old one and now suddenly we're seeing a very large improvement in FPS. Seems like it somehow almost doubled the FPS of our program. Don't know if some bugs regarding Audio/Raspicam&mmal/GPU or som...
by ACouCam
Thu Dec 11, 2014 7:28 pm
Forum: Advanced users
Topic: Disable_L2cache - No boot
Replies: 8
Views: 2601

Re: Disable_L2cache - No boot

Thanks DOM for your reply. Yes our project is indeed both CPU and GPU intensive, now CPU usage is at about 70% (most of it comes from streaming data over SPI about 0.9MByte/s) along with outputting Audio and some other stuff. The GPU then continuously do some heavy calculations together with a conti...
by ACouCam
Thu Dec 11, 2014 8:17 am
Forum: Advanced users
Topic: Disable_L2cache - No boot
Replies: 8
Views: 2601

Disable_L2cache - No boot

Hi! We have a very GPU intensive program running on the Raspberry and wondered if the Config.txt option Disable_l2cache = 1 would speed things up. But instead with this option set to the config file the raspberry won't boot any more and just shows a black screen. Tried this a couple of times and the...
by ACouCam
Tue Dec 02, 2014 9:12 am
Forum: Graphics programming
Topic: Resolutions and cropping
Replies: 1
Views: 1471

Resolutions and cropping

Hi all! We have a project using the Raspberry Cam with the binned 2x2 mode 1296×972 using the full FOV. Short story, after this we show the camera picture onto an LCD 1280x800 screen. Now our question is, what will happen to the camera picture when we show it on the screen? Will it crop 16 and 172 p...
by ACouCam
Tue Sep 23, 2014 12:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI CPU usage
Replies: 13
Views: 4382

Re: SPI CPU usage

One more note about the DMA driver, even when run in interrupt pio mode, it should be faster than the stock driver. This is because the fifo apparently is larger than what the docs say: https://github.com/notro/spi-bcm2708/wiki#fifo-size Ok, this sounds nice. So, one could easily get things faster ...
by ACouCam
Tue Sep 23, 2014 10:54 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI CPU usage
Replies: 13
Views: 4382

Re: SPI CPU usage

ok, so if the CPU now would be stuck for a while in kernel, while transferring and processing the numerous spi data and interrupts then one should be able to lower the overall CPU load by increasing the SPI speed, and thus the CPU is stuck for a shorter amount of time, right? (In my case, when there...
by ACouCam
Tue Sep 23, 2014 9:59 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI CPU usage
Replies: 13
Views: 4382

Re: SPI CPU usage

Ok, how did you come to the conclusion of 0.5 seconds for the bits? In my understanding the physical SPI module is a "free running" module with its own small internal RX and TX buffer. Then when for example the RX buffer gets full or near full the module creates an interrupt to the CPU and the CPU s...
by ACouCam
Tue Sep 23, 2014 8:15 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI CPU usage
Replies: 13
Views: 4382

Re: SPI CPU usage

Joan, Sorry, didn't really get what you tried to explain with the busy spin? The polling now happens every 4ms and is only two-byte long. But when there is a "Yes" reply there'll be a 24.2KB transfer in one big chunk and then continue polling until the next data chunk and so forth. Adding to approxi...
by ACouCam
Tue Sep 23, 2014 7:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI CPU usage
Replies: 13
Views: 4382

Re: SPI CPU usage

Thanks for your input guys, really appreciate it!

I'll have a look at Martin Sperl's drivers. Definitely have to do something about this issue because it is kind of silly that just a 0.9MB/s data transfer takes the major part of the available CPU time.

Thanks,
Jonas
by ACouCam
Mon Sep 22, 2014 7:41 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI CPU usage
Replies: 13
Views: 4382

SPI CPU usage

Hello! We've a rather CPU demanding project involving continuous SPI transfer @16MHz from an FPGA to the Raspberry pi. The data is sent from the FPGA to the PI in chunks with an overall mean transfer rate of about 0.9MByte/s. The system works as follows, first the Rapsberry as the SPI master sends o...
by ACouCam
Wed Feb 26, 2014 6:16 am
Forum: Camera board
Topic: Weird error
Replies: 5
Views: 3259

Re: Weird error

Hi!

Thanks for the suggestion. Although I found my problem, it was the small rectangular-shaped connector above the camera sensor which connects the sensor to the PCB which was loose.

Jonas
by ACouCam
Mon Feb 24, 2014 7:21 pm
Forum: Camera board
Topic: Weird error
Replies: 5
Views: 3259

Weird error

Hi! I just plugged in my Raspi-camera and did all the preparations (enabling it in raspi-config, updating pi to last firmware) but I get a strange error when I try to use it with Raspivid. The error is: "received unexpected camera control callback event 0x4f525245" Anyone got any clue about this or ...

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