56F800/E: question about Interrupts

[jag]

Hi to all.
I was reading the datasheet of the new 56F8037 when a question came to my mind.
I'm thinking ybout the Fast Interrupts and the SW Interrupts.
I'm not sure when the FI are useful, and what are the drawback (if any) of using this kind of interrupt.
And I don't understand what are the SW interrupts and when they should be used.

Someone can give me some examples of use of these two Interrupts (just by word, I don't need the code), in order to understand better the functionality of the 56F800/E core?

Thank You

BYe Jack

[Bentech]

Jack,
  I see no one has replied so I though I would say something. I am using the DSP563xx processor series and if you read the datasheet it tells you a bit about the fast and slow interrupts. There is a big difference and I start by explaining the interrupt process.

 Each interrupt has a two instruction slot in an interrupt vector table. When an interrupt occurs, the program counter is frozen and these two instructions are fetched and executed. Normally a jump instruction is inserted in the table which jumps to the ISR so the interrupt routine can be executed. This is a long interrupt.

  A fast interrupt is used if neither of the two instructions are a jump insturuction. Here, the two instuctions are executed, and the program continues. The benefit of a fast interrupt is that the state of the machine is not saved and all the overheads associated with a jump are not there making it very fast.

  So basically, if you can execute your interrupt in only two instructions, then a fast interrupt can be used. Here, you may only set a flag, or use some special instructions that have been designed so you can transfer data between peripherals.

  For more information, check out the DSP56300 Family Manual and look at section 2.3.2.

I hope that helps.

Cheers,
  Carl