I have a smart card-like miniSD card (it's a javacard as far as I know) and I'm trying to write an emulator for it that runs on Windows and Linux. The emulator will be used in software integration tests. I want to test my client without using the actual hardware for several reasons. One reason is that the actual hardware will change its state irreversibly and doesn't allow a complete reset.
The device implements a mass storage with FAT32 file system. It contains a special device file that is being used for controlling the device via simple file write/read operations.
My goal is that the virtual (emulated) device appears with drive letter in Windows explorer as soon as the emulator is started, similar as if someone would actually plug a real device.
I wonder if there is any open software project that I can base my program on? The biggest challenges are obviously
Providing/developing a "virtual" (USB/SD) mass storage device
Intercepting file I/O operations on the special device file.
According to Wikipedia, device files are a common way to simplify driver development. So I wondered if there are existing emulation solutions for driver developers. At least I couldn't find any.
Simulating the device file itself would be an important first step. My first idea was to use a normal file and to communicate with the client by actually reading/writing to this file while observing it. I.e. clear the file as soon as the client wrote to it and write the response into it. I don't know if this could work at all. One problem is that the client doesn't open the file with shared mode, so my simulator cannot access it at the same time.
Then I found out that QEMU can emulate mass storage, however it seems that it only supports image files and that probably doesn't allow device file.
Microsoft has some documentation about how to write USB device emulators and drivers but it seems to be very complex and I wondered if there is an exisiting solution that could be extended:
Finally there is the USB/IP Project, but I don't know if it is helpful as I still need to develop a driver and then I'm back at the complex MS documentation above.
I am working with Linux software on DE10-nano board and I need to perform a small modification to default FPGA configuration (add pull-ups on GPIO lines).
The user manual points to DE10-Nano System CD\Demonstrations\FPGA\Default as default project which suppose to produce the factory FPGA configuration.
I compile it, convert SOF to RBF, and put the RBF on SD card for U-Boot to load.
U-Boot programs FPGA (I get orange LED on) and then fails to load Linux device tree (I get ERROR: Did not find a cmdline Flattened Device Tree message via COM port) although the same device tree file is in the same place on SD card.
Am I using the correct Quartus project?
The only solution that worked for me (loading my own .rbf file with the unmodified Linux Angrstrom from Terasic) was to use the SD card images from:
http://download.terasic.com/downloads/cd-rom/de10-nano/linux_BSP/
I used the de10_nano_linux_console image. I used the sof_to_rbf.bat file to generate the .rbf file, ensuring that compression was turned on and the output file name was soc_system.rbf.
Any other method I tried with the SD card resulted in the error message the OP posted relating to the Device Tree.
I'm working with a USB device in Linux and have written a library to control this device.
Without going in to TOO many details, the device uses a standard UART protocol, so all I have to do is open a serial connection with open, configure the relevant parameters like baud rate, stop bit, parity, etc, etc, and start bit-banging registers.
The library works fine, however, it its hard coded to assume that this device is /dev/ttyUSB0. That is, this is what I pass to open. If open fails, I exit.
What I would like to do is detect that this device is present, regardless if it's /dev/ttyUSB0, /dev/ttyUSB1, etc. And even detect if there are multiple of these devices connected.
I can write code to poll certain registers on the device that will return serial number, product ID, etc, so I can detect that what is on the other end of the USB is indeed my device... but how can I find a list of connected USB devices, again, in native C?
OR is there a more elegant way of doing this, such as interfacing with it's kernel module, or something? I can provide the USB driver it actually uses, but I'm sort of lost when looking through the code.
Thanks for any insight.
The elegant method is to use udev to create a descriptive symlink for your device when it is connected. Add a line something like this to /etc/udev/rules.d
SUBSYSTEM=="tty",ENV{ID_MODEL}=="My_FlowMeter_Model",ENV{ID_USB_INTERFACE_NUM}=="00",SYMLINK+="flowmeter",RUN+="/bin/su pi -c /home/pi/record-flowmeter.sh
That's a very slightly modified version of an actual udev rule my research group uses to collect data from USB devices connected to battery-powered Raspberry Pi boxes. It also runs a script automatically, which has commands like
stty -F /dev/flowmeter 500000 -ixon -echo -icanon
If you want to know the "real" device filename, you could do readlink /dev/flowmeter. But for most uses you can just use the link: fd = open("/dev/flowmeter"); (or pass it as an argument to your program)
Naturally you should replace flowmeter with a short name for your own device, as well as updating the ID_MODEL based on the output from lsusb.
Multiple devices are a bit more complicated, but there are plenty of examples of udev rules out there.
On Linux, the information you are looking for is in the /sys filesystem, specifically under /sys/bus/usb/devices. From there you will need to search the filesystem to find your device.
For example, I just plugged a USB-serial dongle into my Linux (kernel version 2.6.35) and the device appeared under /sys/bus/usb/devices/2.1-8. Here, I am able to find that this is my device by vendorId:deviceId by checking the files idVendor and idProduct. Here, there is a directory named 2.1-8:1:0 which contains a directory named ttyUSB0.
Obviously, to find your device you will need code (or a shell script using find) to scan the directory tree, looking for the right entries.
I want to create a USB driver, so my own C application to be able to get into my flash drive and take information from the imported flash drive.
OS: Windows
I start my app contains my USB driver and I plug-in my flash and its shows in Explorer that this drive is plugged and it is accessible, while that's happening, my app is checking that file data.txt EXIST if that file exist, program run next function, if not program, my program runs down/exit/!
If you are looking for a programmable USB dongle, I suggest inspecting this SO thread: Programmable USB dongles
The Windows Driver Kit should simplify your work or atleast help you at the start.
I am new to C and am trying to write a program that syncs files on my computer to a USB device. It currently works my me cd'ing to the directory that the device mounts to and typing "myprog init" which creates a .myprog file. The idea then is that when a USB device is connected my program checks for the .myprog file, if it finds it then it syncs. Problem is that I can't figure out how to detect when a new USB device is connected.
I am writing the program for Linux (I'm using Ubuntu 9.04) and using GCC.
Thanks for any help :)
Look into udev documentation for this (writing udev rules).
Also have a look at this stackoverflow thread.