I have been referencing the startup files for the "Basic Tools" project. Specifically I have been looking at the: 1) macros setup function file (SAM7.mac); 2) the compiler linker file (at91SAM7S64_NoRemap.xcl); 3) the code startup assembly file (Cstartup.s79). My question is this, I am trying to use this project as a template but set up the environment for my own application, which uses internal flash only for code. I need to understand all aspects of these startup files in order to determine if I need any changes for my application.

One thing I'm not sure I understand is how the IRQ_STACK_SIZE and the CSTACK_SIZE were chosen. Shouldn't the IRQ_STACK_SIZE be 128 bytes versus 64? That is, 32 possible interrupt vectors via the AIC with 4 bytes for each vector. Or was this size chosen to represent different requirements? What about the CSTACK_SIZE selection? Was it just an arbitrary large number chosen?

Thank you for your assistance,
Regards,

Hi Peichler

Yes of course you can use the Basic tools for a template.

I advice in the first time to use the RAM feature for little code, however when the code increase you can use the Flash workspace for debug your application.(the Cstartup it's the same ).

The IRQ_SATCK_SIZE it used only if you have some interruption, you can check in the IRQ_Handler_Entry piece of code for interrupt management this code use only 2 stack spaces for register and after use the standard C_SATCK.
IRQ_STACK_SIZE EQU (2*8*4) ; 2 words per interrupt priority level
The IRQ_STACK size needs only 64 bytes and not 128
Is not dependent of the vector number it’s dependent of the nested interrupt (8 for the ATMEL product)
The CSTACK size corresponding at the stack needed by the C code and depending to your application.
1) The file SAM7.mac is the iar script file for the Flash connection, these macro are runnunig when the IAR tools download the program file ( in this case this macro it used to debug and not for download )

2) at91SAM7S64_NoRemap.xcl is the memory description file for the linker operation.

3) The startup file it the same for the both cased .

Thank you for your assistance JPP, I think I have it pretty much understood now.