Hi everyone, I'm new here I want to know if it's possible to program At91SAM7x256 without need to use a JTAG connector and cable. Thanks
You can program it over USB with the SAM-BA bootloader. See http://www.atmel.com/dyn/products/tools_card.asp?tool_id=3883 for more information.
thank you for help I want to ask if it's a good practice to port linux on this MCU
Akrmi Yaacoub wrote: > I want to ask if it's a good practice to port linux on this MCU It is an ARM7 part so has no MMU. There are distributions of Linux that will run without an MMU (uClinux for example), but just because you can, does not mean you would want to. Lack of memory protection removes one major advantage of using Linux. Also no usable Linux distribution will run in the on-chip memory resources; you'll need a board with external RAM and unless you boot from removable media, external Flash too. If you need hard real-time performance and small memory footprint, Linux would not be appropriate. If you want to take advantage of communications devices and storage media of various types Linux may be a good choice. Consider something more suited to small devices such as eCos if you need real-time and extensive device support, or FreeRTOS is you simply need a real-time preemptive priority based scheduler. Clifford
I agree, this is not the kind of controller that you would run Linux on. If you are interested in playing with Linux on an ARM controller, use one of the bigger ARM9 parts with a MMU, like the SAM9 series. But in any case you will need external Flash and RAM and a whole lot of infrastructure, so it's best to start with a board that already comes with a working Linux distribution, otherwise you may be soon get frustrated.
My application needs an I/O (LCD, SD, GSM via rs232) management with a soft real time performance and not a lot of data to store on memory. I know that it's not necessary to make it with embedded linux kernel But I want to do so to familiarise with embedded linux. Do you advise me to switch to an ARM9 MCU if so can you, please, recommand me a low cost board that have these features? Kind regards
How much is "low cost"? To run Linux sensibly you need probably an ARM9 at 200MHz with >=16Mb external RAM and >=4Mb of Flash. That is just teh requirement to get the OS to run. Linux is a general purpose OS, if your application is very specific and small, you will be spending more on hardware to support the OS than is strictly necessary to implement the application. I suggest then that you simple Google "ARM9 development board" if you still think you need this. I think eCOS may be more appropriate however.
Ok thank you, I got it ecos or freertos are the more suitable for my application. and what about distributions like RTLinux can it run inside an MCU with an MPU but not MMU? Oresama
oresama wrote: > and what about distributions like RTLinux can it run inside an MCU with > an MPU but not MMU? > You are really stuck on this Linux thing aren't you!? That is a question probably best answered by checking out the project's own web site. RTLinux however has even more complex requirements that regular Linux. Despite its name it is not in fact a Linux distribution, it is a VM that runs a real-time micro-kernel with Linux as a virtualised guest OS. So not a chance on an ARM7 IMO.