FIQ Error

mayii wrote on Tuesday, March 18, 2008:

Hi all,

Controller: AT91SAM7S256
Dev Board:  AT91SAM7S-EK
Compiler:   IAR 5.11

     I have downloaded demo project provided for the above said configuration, compiled and transferred it to the target using ATMEL SAM-ICE (J-Link). But when I say run it hangs when it tries to execute the following line

orr     r0,r0,#FIQ_MODE                     ; Set FIQ mode bits

and comes to the following section of the code

        ldr  pc,[pc,#+24]             ;; Undefined instructions

I guess a interrupt is getting generated. But cant understand it fully.
Looking forward for replies.

davedoors wrote on Tuesday, March 18, 2008:

This is in the startup code right, before main() is called? All it does is set r0 so nothing that could cause it to jump to the FIQ handler. Does the program hang when you run it without the debugger also? It could be the debugger is not initializing the micro correctly so there is an FIQ pending. I don’t think this can be the case though as setting the processor into FIQ mode is very different from actually generating an FIQ.

davedoors wrote on Tuesday, March 18, 2008:

more -

I note you are using the S256. Did you change the target device in the project settings to be for this device, and select the correct linker script. I think the demo yo are basing it on is for a SAM7 with less memory.