1. Home
  2. Embedded Programming
  3. Microblaze and low level interrupt example

Microblaze and low level interrupt example

currently i try to write a simple interrupt driven timer example without using the provided help functions in the xilinx edk. The goal is to reduce the code size for a minimal system configuration. The xilinx functions blows up the code, so i try to program the timer and interrupt controller components by my self. So these works, i receive the timer interrupt. My problem is now, that the handler function doesn't return correctly and the stack grows up. I use rtib (microblaze) for the return from interrupt. Any ideas, why these doesn't work correctly ?

Perhaps somebody has a good reference about the low level programming of the microblaze.

Reply to
Andreas Wassatsch
Loading thread data ...

Hi,

You should use rtid for returning from an interrupt on MicroBlaze. Since you have used your own versions of the handlers, you also handle the stack yourself. MicroBlaze will not pop/push anything to the stack in hardware, everything is controlled by instructions.

If the stack growns, I think you are missing a restore of the stack pointer somewhere in the code. Check that your handler restores the stack pointer to it's previous values when you do the rtid instruction.

You are mostly likely creating space on the stack in the beginning of your handler with something like addik r1, r1, -12 This creates space in the stack for 3 words, register r1 is normally used as stack pointer and stack pointer grows downwards in memory. You should then have something near the RTID that restores the value of r1 like addik r1, r1, 12

Göran

Reply to
Göran Bilski

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.