Hi, Is there a device driver and software exemples available to use the GPIO of the friendly ARM mini 2440 ? Thanks, Have a Nice Day, All of You
I guess you have seen the buttons_test.c in the example code? I found this on AVRfreaks.net for the AVR32, search for this title <Example code to initialize new spi-gpio driver>, maybe it will be helpful.
http://www.mjmwired.net/kernel/Documentation and look for gpio.txt Went searching for /sys/class/gpio in the factory install and couldn't find it. Another one to look at is: http://foxlx.acmesystems.it/?id=22 There is an example: gpiosyscalls.c which looks useful. They have a lot of information, which would help one to at least get some direction. I'll talk to the S/W guys at work about some GPIO examples.
You need to recompile the kernel to have a working /sys/class/gpio. Anyway i can't understand how to use it. this is my /sys/class/gpio mini2440:/sys/class/gpio# ls export gpiochip128 gpiochip192 gpiochip64 unexport gpiochip0 gpiochip160 gpiochip32 gpiochip96 mini2440:/sys/class/gpio# cd gpiochip0 mini2440:/sys/class/gpio/gpiochip0# ls base label ngpio subsystem uevent mini2440:/sys/class/gpio/gpiochip0# cat base 0 mini2440:/sys/class/gpio/gpiochip0# cat label GPIOA mini2440:/sys/class/gpio/gpiochip0# cat ngpio 24 mini2440:/sys/class/gpio/gpiochip0#
10Q? Would you like to tell me what worked well? I tried to compile gpiosyscalls.c but the compiler I am using in Code::Blocks can't find "linux/gpio_syscalls.h" So, I am off searching for that library. Regards, Dave
Pasquale, Could you tell me how to modify config_mini2440_n35 as found on the factory DVD to enable GPIO? I find it a bit odd that they go to the trouble of giving you all those connections to GPIO, on some nice headers, and then don't enable that capability. Thank you. Regards, davef
i recompiled the linux kernel (source downloaded from the friendlyarm.net website) after changing its configuration, to include drivers for gpio. the chinese manual (again, from friendlyarm.net download page) actually tells us how to do that, please translate chapters 5.3, 5.4, (for gcc toolchain installation) and chapter 6 (for the configuration menus tutorial and actual kernel compilation) with http://translate.google.com (which i did). now "/sys/class/gpio" exists in my system... -irfan-
irfan, Thanks for the pointers. Fortunately, a fellow I work with also bought a FriendlyArm and is able to translate the sections you mentioned. Regards, Dave
< for /sys/class/gpio just add CONFIG_GPIO_SYSFS=y into .config file The problem I had with this was I couldn't find it using menuconfig on the FriendlyArm distro (220.127.116.11). If you could tell me where to find it, at least that would be useful to know. I have since moved to using the kernel on the buserror site Thanks, Dave
I did the same as Irfan and i'm able to access all gpio pins. I built my own driver using the s3c2410_gpio_setpin, s3c2410_gpio_getpin and s3c2410_gpio_cfgpin functions. regards
Hi davef Where you able to find "linux/gpio_syscalls.h" and the associated libs src. If you have please post it on the net via a file sharing site. regards --fatbrain
fatbrain, I would look at: http://lxr.linux.no/+trees for any code you want. I did not get any further with GPIO in general and GPIO_SYSFS in particular . . . working on rootfs and a web server. Good luck
Hola a todos. Quisiera saber como tenemos acceso a todos los pines del puerto GPIO, tengo la version de kernel 2.6.13 , no estan el sys/class/gpio que han comentado,dicen que deberia recompilar el kernel, especificamente a que parte se refieren, he buscado el .congig y la unica opcion relacionada con gpio esta ya montada, Entonces no tengo un archivo descriptor para manejar el gpio. Gracias por su tiempo.
Hello everyone I am relatively new to handling the linux kernel I have the linux kernel 2.6.29. I recompiled it to include the gpio drivers But now the size of the zImage is going beyond 2MB. What seems to be the problem? Have i included some extra options while compiling? Thanks in advance for any help Cheers
hey, i started here a little open source lib for gpio, but still working http://sourceforge.net/projects/gpiolib/
I realize that this thread is somewhat old but here is a helpful link for enabling gpio support...this creates the /sys/class/gpio directory http://ebrombaugh.studionebula.com/embedded/mini2440/index.html
hey , i am successful in using the 34-pin GPIO in Qt 4.6.3 program for 3 stepper motor driver pulse-engine using 9 Gpio pins, 3 for each motor .. 1.Enable 2.direction & 3.step this was done by enabling kernel gpio support and compiling the kernel. My problem is when i try to toggle gpio using Qts timer the maximum pulse freq i get is only 450HZ ....i need freq in few kilohertz ..what approach should i take for this is it Gpio access problem from user space ,Qt program overhead or linux kernel schedular tick issue and how can achieve those kilohertz freq(max 10khz for each motor).... Anybody willing to help...? Thanks in Advance
Do some research on writing a kernel driver for GPIO rather than working through sysfs. I don't know how much faster that would be. Then some people manage to use various "real time" patches to get higher speed. Then get rid of the operating system and write "bare metal" C code, then do it in assembly. It is a difficult trade-off . . . if you want a fancy GUI, like Qt and have good control over hardware I would suggest to use the GUI to talk to small 8 bit uPs (over serial) that can do this more effectively.
I agree with Davef (by the way, are you the same davef on TinyCLR forum?) that you should offload the IO to an external processor and do all the GUI with QT. No matter how much you try, Linux or Android are just not a real time OS so you can not guarantee latency. We do this very thing with a control system for a large hyrdraulic machine. All the GUI is done under a Windows application but the actual sampling and control is done by an microcontroller board communicating over USB. Dave...
No to TinyCLR. Was quite active on AVRfreaks during my uP formative years. Thanks for the reminder about USB rather than serial. There is a 8bit USB series from ATMEL and also a USB library called LUFA that you can run on their older 8bit ATMega series.
Just someone using the same name then! :o) If the AVR does not have built in USB I just use the FT232R from FTDI as I have found that it just works 100% every time. In fact, I have used that chip to convert legacy RS232 designs to USB over the years. Dave...
There are AVR chips with USB capability. This is even better: http://www.pjrc.com/teensy/ A guy at work has been using these for the last 6 months or more. Time to have a chat with him.
I often just build my own PCB's as by the time you buy these and wire it all up, you have quite a mess. Good for home hobby but not much use for commercial applications other than development and learning as a start on a new processor. You can get 1 off PCB's these days for little cost that it makes more sense just to build your own (assuming you have the know how anyway) and then you can include power supply, outside world screw connectors or plugs etc. Dave...