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Hi,
I have a couple of executables [ while(1) {...} loop programs within a main() function ] generated ( hex or bin or s19 ; for simplicity lets say hex ) and I want to allocate each hex file at a specific starting address in the flash memory, so that in a main program I can jump to a specific starting address depending on the input to execute the present code.
1. Any help to solve this problem ? 2. Is there any way to merge these hex files together and then I can can jump to their specific location ?
Thank you, Walid Farid
-------------------------------------- More about the problem ------------------------------
So, I've 3 developed projects where each project interfaces with specific peripherals on the development board. And, I want to load all 3 hex files ( or any other form of executable ) corresponding to each project to the flash memory and execute one of these codes at a time from the flash. I'm not sure why did you mention executing the code from the RAM, if I can execute it directly from the flash.
I thought, if I'm able to load the 3 hex files to the flash memory, I can load a 4th hex file, which given a specific input will run one of the 3 hex files at a time directly from the flash.
I'm using KEIL-MDK evaluation version and looking at the hex file, I can see that the starting/entry point of the code is 0x8000_00ED. So, I'm sure that all hex files will have the same entry point.
In KEIL-MDK, If I changed the code memory area to start at a different location than 0x8000_0000 ( say 0x8000_0100 ), will this change the starting/entry point ? Will the bootloader start executing the code at 0x8000_0100 which maps to the RESET routine? Or does the bootloader, regardless of the entry point in the hex file, places the code starting at 0x8000_0000 ?
I hope I clarified what I want to do ... so, regardless of or with regard to using hex files, how can I solve this problem ?
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P.S. : This question has already been posted on the STM32 forums
Walid,
Save yourself a headache (even though you can learn a lot by doing what you were thinking of). Why not make one application with 4 functions or, alternatively - libraries, that represent the components you need to program. Then, in your program's startup you decide which function to execute based on the position of a jumper, an incoming serial message etc...done! Why make life harder when not necessary...?
Hi Tamir,
Thank you for the suggestion. I guess that the merging way is what I'll do at the end after having no other option. However, as I mentioned, these different components use sometimes the same interrupt service routines and so on, so they overlap. That said, merging them will take more time, as they are not just simple functions. So, I'll give it some time to investigate the other option and then will decide.
Thank you, Walid
That is inherent in the nature of making a system that can support multiple applications!
IF you really want to proceed down this track then, to do it properly, you would have to do like "real" operating systems do and provide a "driver" layer that does all the direct hardware access.
You can totally avoid the issue by having just 1 application loaded at any one time!