DM355 Interrupt Controller

Mato Hattori

Hello,

I would appreciate if someone teach me how to program Interrupt Service Routine for DM355 processor.

I'm not using Linux or any sort but writing a 100% raw registers access program.

I enabled Timer interrupt, and confirmed the FIQ register reflects the occurance of interrupt.

I set INTC's EABASE register to 0, and placed a Blanch instruction at memory location supposed to be refered by FIQENTRY register as the interrupt occured.

But it seems that the Blanch instruction has never been executed.

What did I do wrong?

over 16 years ago

0 Mato Hattori over 16 years ago

Prodigy 150 points

Well, after a few weeks of struggle, I found an answer by myself.

There is a register accessible only by ARM assembler.

I had to Clear bit 6 of CPSR register to enable FIQ.

Assembler code to do this is like below;

MRS  r0, cpsr
BIC  r0, r0, #0x40 ; ENABLE FIQ
MSR  cpsr, r0

Refer to "DM335 ARM Subsystem User's Guide" 3. ARM Core 3.3. Processor Status Registers.

Hope someone finds this useful.

0 Ed Sutton over 11 years ago in reply to Mato Hattori

Intellectual 885 points

Mato,

Thank you for taking time to post this. Nearly five years later I found this *very* useful.

Can you please post a code snippet on how you "set INTC's EABASE register to 0, and place a branch instruction at memory location supposed to be refered by FIQENTRY register as the interrupt occurred."

I think I have it all wrong in my code sample pasted here:

ARM interrupt handler and initialization example in C ( bare-metal no OS ) ?

-Ed

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DM355 Interrupt Controller