topic Re: Interrupts - MC9S12XDT512MAA in S12 / MagniV Microcontrollers

Interrupts - MC9S12XDT512MAA

Gerald1 — Mon, 11 Feb 2008 22:23:54 GMT

are there software interrupts (!= hardware interrupts like, signal rises to high on a port) existing on a MC9S12XDT512MAA?

cu

Added p/n to subject.

Message Edited by NLFSJ on 2008-02-11 01:55 PM

Re: Interrupts - MC9S12XDT512MAA

DPB — Tue, 12 Feb 2008 17:05:04 GMT

Hello

There is indeed a software interrupt available on this device in the form of the SWI instruction.
This is a non-maskable interrupt and is listed in the interrupt vector table on page 73 of the S12XD-Family reference manual.
It is described in more detail on page 351 of the associated CPU reference manual at.....
http://www.freescale.com/files/microcontrollers/doc/ref_manual/S12XCPUV1.pdf?fpsp=1

DPB

Re: Interrupts - MC9S12XDT512MAA

Gerald1 — Tue, 12 Feb 2008 17:56:32 GMT

i am using the codewarrior c-compiler.

in the headerfile (mc9s12xdt512.h) i saw:
/**************** interrupt vector table ****************/
#define Vswi 0x0000FFF6

//---------------------------------------------------------------
//my code:

#pragma CODE_SEG __NEAR_SEG NON_BANKED /* Interrupt section for this module.

interrupt void Vswi(void)
{
// ...code...
}

#pragma CODE_SEG DEFAULT

how should i enable swi interrupt by using -> EnableInterrupts?
and how could i set and clear the swi interrupt?

bye

Re: Interrupts - MC9S12XDT512MAA

Steve — Tue, 12 Feb 2008 21:39:19 GMT

SWI does not need to be enabled or disabled and there is no flag clearing required - see the SWI instruction in the CPU glossary for more info.

If you need more control or more software interrupts you can use the XGATE software triggers (there are 8 in the XGSWT register) but remember to direct them to the CPU. In that case you will need to enable interrupts (CLI) and clear the relevant flag on completion.

Re: Interrupts - MC9S12XDT512MAA

JimDon — Tue, 12 Feb 2008 21:44:03 GMT

Also be aware that some Freescale debuggers use SWI for code running in ram and that some RTK's use it to switch task (UCOS for sure).

You may wish to find another mechanism to accomplish this.