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ARM7TDMI processor mode

shan S
Note: This was originally posted on 23rd November 2012 at http://forums.arm.com

I am using the ATMEL91SAM7SE512 controller with ARM7TDMI processor.The application is running in the User mode .

when the interrupt(IRQ) occurs processor must switch to IRQ mode,then it should go to the IRQ handler routine.

here application developer part is to tell the IRQ handler address only.so who taking the responsibility to change from User mode to IRQ mode.

whether the core itself switched into IRQ mode using hardware setup or some low level routines(program) avail.i struck in this point , i cant

proceed further on this study of ARM7TDMI processor.


please tell me your thoughts regarding this query.

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thanks
shan.s



Parents
  • Note: This was originally posted on 26th November 2012 at http://forums.arm.com


    Assuming that interrupts are enabled (CPSR.I=0) the processor will automatically switch to IRQ mode when the IRQ is signaled.  It will also automatically start executing from the IRQ entry in the vector table.

    It is up to the boot code to make sure the vector table is in place, with the correct handlers set up.




    Hi,
          Thanks for ur answer. it is fine that in boot program we are filling the exception vectors.
    may i know about exception entry and exception exit code.they given the exception entry and
    exception exit code (ASSEMBLY) in ARM7TDMI processor architecture document.it is not in
    my project code( Boot program(startup.s) + application program).simply we cant assume  that mode
    switch were happened and interrupt handler routine is called.


    thanks
    shan.s
Reply
  • Note: This was originally posted on 26th November 2012 at http://forums.arm.com


    Assuming that interrupts are enabled (CPSR.I=0) the processor will automatically switch to IRQ mode when the IRQ is signaled.  It will also automatically start executing from the IRQ entry in the vector table.

    It is up to the boot code to make sure the vector table is in place, with the correct handlers set up.




    Hi,
          Thanks for ur answer. it is fine that in boot program we are filling the exception vectors.
    may i know about exception entry and exception exit code.they given the exception entry and
    exception exit code (ASSEMBLY) in ARM7TDMI processor architecture document.it is not in
    my project code( Boot program(startup.s) + application program).simply we cant assume  that mode
    switch were happened and interrupt handler routine is called.


    thanks
    shan.s
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