I am new at embedded system programming. I am working on a device that uses an 8051 chipset. I have noticed in the sample programs that when defining variables, sometimes they use the keyword xdata. like this... static unsigned char xdata PatternSize; while other times the xdata keyword is omitted. My understanding is that the xdata k...
I have a simple bootloader, which initializes and prepares SDRAM. Then it loads an application from the Flash and starts it at some address in the RAM. After the application has finished its execution, the system does restart. There is no system stack. Now, I would like this bootloader receives control back after an application finished...
I am trying to understand what the following line of the worst-ever-seen C code (from uboot project) mean: rc = ((ulong (*)(bd_t *, int, char *[]))addr) (bd, --argc, &argv[1]); What is it? A function call? Can it be more readable? Thanks in advance for your help! ...
I'm in the process of developing a software library to be used for embedded systems like an ARM chip or a TI DSP (for mostly embedded systems, but it would also be nice if it could also be used in a PC environment). Obviously this is a pretty broad range of target systems, so being able to easily port to different systems is a priority....
I heard about eCos and it looks like it would be fun to play about with as a hobby project. Can anyone recommend a reasonably priced development board.If it doesn't add too much to the cost, I'd like to have a few buttons to press (and detect the press programatically) and an LCD for some debug output. Ethernet would be nice (hmm, maybe...
I dump my RAM (a piece of it - code segment only) in order to find where is which C function being placed. I have no map file and I don't know what boot/init routines exactly do. I load my program into RAM, then if I dump the RAM, it is very hard to find exactly where is what function. I'd like to use different patterns build in the C ...
Ok, you can tell by my name that I'm new to this, so please understand if any "errors & warnings" I am trying to build rootfs image for at91sam9260 controller, for which I'm using buildroot. The problem is that it is not able to download the package "ftp://ftp.uu.net/graphics/jpeg//jpegsrc.v6b.tar.gz". And on top of that, I'm also not a...
I'm trying to upload a compiled program to a microcontroller.. well my problem is not in programming or uploading things.. my problem is what to upload u.u The program is in C and was compiled with SDCC. The mcu is an AT89S8252 by ATMEL. I built a simple parallel port programmer following MCU protocols for serial programming as stated ...
I wish to learn more about the inner working of the computer, to enhance my knowledge about embedded system developement. At work, I never get involved with the low-level details (such as, the GDT, the loader of the code from flash to RAM, etc) as all these are already written. I'd rather not buy any other hardware currently. Is there ...
When you say "optimization", people tend to think "speed". But what about embedded systems where speed isn't all that critical, but memory is a major constraint? What are some guidelines, techniques, and tricks that can be used for shaving off those extra kilobytes in ROM and RAM? How does one "profile" code to see where the memory bloat...
While, as far as I remember, IEEE 754 says nothing about a flush-to-zero mode to handle denormalized numbers faster, some architectures offer this mode (e.g. http://docs.sun.com/source/806-3568/ncg_lib.html ). In the particular case of this technical documentation, standard handling of denormalized numbers is the default, and flush-to-z...
Background: The compiler may insert padding into a struct to make it's members align better. This will result in the sizeof the struct being larger than the sum of the sizes of it's members. Reordering the members of the structure so they pack better can remove the need for the compiler to pad in this manner and make the struct smaller s...
hello, i have been debating which OS to use for a car pc.. and ubuntu netbook remix (UNR) and moblin seem to be the best ones suited for a small touch screen.. however, i want to use an OS which has good support from the community.. and was confused upon reading the wikis for each of them which says that both OSes are built by canonic...
The article was about an embedded device containing a memory chip, processor and could be extended with bluetooth wifi and an other RF transmitter. The manufacturer developed a framework which contained: memory managment, TCP/IP stacks and more. Anyone has an idea what it was? thnx ...
Has anyone tried running any linux distro from USB on the ICOP Technology Ebox : link ...
i am using busybox and linux 2.6.32.4. my configuration is based on fedora 12. and started mdev according to mdev document. but i cant see my modules like network adapters and plugged usb devices. is there thing must be done? mdev commands (after mounts): echo /sbin/mdev > /proc/sys/kernel/hotplug /sbin/mdev -s ...
There are tons of programming related blogs around the Internet, but I'm looking for resources that focus on embedded systems software and naturally also hardware things. What blogs, podcasts, newsletters, web sites etc. do you read to learn new things? Are there embedded systems professionals that every embedded engineer should be awar...
I'm interested in any comparisons between GCC and Greenhills C compiler with regard to memory footprint of generated code specifically on ARM platforms. Are there any benchmarks or comparisons for these compilers? Has anyone had any experience here that they'd like to share? ...
When using the CCS compiler's multiple compilation units feature, I stumbled upon what seems to be a pretty serious bug: The setup is a header file defining a #bit in a #byte, two compilation units #include-ing the header file and a function referring to said #bit. It seems that the function's code (specifically using the correct addre...
How are you meant to initialise the program using Qt embedded? At the moment I'm using QMainWindow but this means including a lot extra when configuring Qt and makes the applications a lot bigger when compiling them statically.What are you meant to use in place of QMainWindow? I don't need anything like maximise buttons - using a small s...