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by Markus989
Fri Jan 24, 2014 1:16 pm
Forum: Advanced users
Topic: CONFIG_PREEMPT_RT on Raspberry Pi
Replies: 88
Views: 49668

Re: CONFIG_PREEMPT_RT on Raspberry Pi

Hi, I'm also not a linuxkernel expert, but i have one idea with which the latency problem might be solved. Without the sd-card-patch we don't have the latencyproblem but we cannot boot from sd-card. So, is it possible to detect somehow inside our sd driver wether the kernel is booted or not?? If yes...
by Markus989
Mon Jan 06, 2014 3:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI driver latency and a possible solution
Replies: 241
Views: 136769

Re: SPI driver latency and a possible solution

Make use of spi_async for anything that is timing critical, then you shortcut the context switch! What you may end up doing is scheduling your (read) message from a timer interrupt triggering at regular intervals. That should be the most consistent method from a scheduling perspective - at the wors...
by Markus989
Sat Jan 04, 2014 11:13 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI driver latency and a possible solution
Replies: 241
Views: 136769

Re: SPI driver latency and a possible solution

Thanks msperl for the overview of the procedure which is taken place!!! I already investigate the code to find those latencies, but Im new to linux module development, so its not that easy for me. Sorry for the poor description I gave :| I'm not using the spidev driver, I work on implementing a spi ...
by Markus989
Fri Jan 03, 2014 11:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI driver latency and a possible solution
Replies: 241
Views: 136769

Re: SPI driver latency and a possible solution

Hi all, I have a question concerning the spi performance with your patch when sending only 1 Byte per spi-message. My SPI-slave expects between every Byte a GPIO -Signal(called a framesignal). This means for me its only possible to send the spi message byte after byte, with a gpio trigger in between...
by Markus989
Sun Jul 07, 2013 7:03 pm
Forum: C/C++
Topic: Networkmodule - open-function is called automaticly
Replies: 0
Views: 362

Networkmodule - open-function is called automaticly

Hi all, i want to program a network ethernet module which uses SPI as the hardwareinterface. My problem is when I load the Module with the insmod command, the open-function is called automaticly. But I need to call this function with the commandline, with ifconfig eth1 up. With an none ethernet dirv...
by Markus989
Thu Jun 06, 2013 2:47 pm
Forum: Deutsch
Topic: SPI Protokoll Driver am Kernel anmelden
Replies: 4
Views: 2512

Re: SPI Protokoll Driver am Kernel anmelden

Genau(soll später ein Netzwerktreiber werden der über SPI angebunden wird), als erstes möchte ich allerdings erst einmal einen Loopback über SPI hinbekommen, wofür das spi_example benutzt werden kann. Ich habe den üblichen spidev-Treiber wie auf ( http://www.brianhensley.net/2012/07/getting-spi-work...
by Markus989
Thu Jun 06, 2013 9:35 am
Forum: Deutsch
Topic: SPI Protokoll Driver am Kernel anmelden
Replies: 4
Views: 2512

SPI Protokoll Driver am Kernel anmelden

Servus, ich bin gerade dabei einen SPI-Treiber für das RPi zu schreiben. Zunächst wollte ich durch das Verbinden von MISO und MOSI einen Loopback realisieren. Dazu hab folgenden Treiber als Beispiel genommen: http://elk.informatik.fh-augsburg.de/pub/elinux/ngw100/AVR32743/spi/spi_example.c Er lässt ...

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