topic Re: ISR in Kinetis L in Kinetis Microcontrollers

ISR in Kinetis L

vivacious — Wed, 06 Feb 2013 12:46:12 GMT

Hi,

I am looking to write an ISR in C (bare metal) for one Kinetis L.
However I didn't get any procedure to setup any particular ISR.

Can somebody guide me where should I look for these details?

.....Still better if I can get an example code.

Re: ISR in Kinetis L

marcopalestro — Wed, 06 Feb 2013 13:18:10 GMT

Hi Vivek,

I can tell you how I got working ISR for Kinetis, but I guess it depends on the toolchain you're using.

With IAR Embedded Workbench, I just declare the ISR like a normal routine:

void lptmr_isr(void)

{

lp_seconds++;

LPTMR0_CSR |= LPTMR_CSR_TCF_MASK; // write 1 to TCF to clear the LPT timer compare flag

}

In the example I use LPTMR for 1 second interrupt; I have a file named vectors.c taken from the sample code. It declares an array and forces it to be allocated in the intvec segment:

#pragma location = ".intvec"

const vector_entry __vector_table[] = //@ ".intvec" =

{

VECTOR_000, /* Initial SP */

VECTOR_001, /* Initial PC */

VECTOR_002,

VECTOR_003,

...

The entries VECTOR_*** are defined in vectors.h

#define VECTOR_000	(pointer*)__BOOT_STACK_ADDRESS
#define VECTOR_001	__startup
#define VECTOR_002	default_isr

you just have to substitue the right entry with your ISR. I'm working this way on KL15, KL25, K70 families.

Regards

Marco

Re: ISR in Kinetis L

vivacious — Wed, 06 Feb 2013 17:36:06 GMT

Thanks for your response Marco....though I should have mentioned that I am using CodeWarrior10.3.......

But I think this should help.......Let me check.

Looking forward to more explanations/responses ......like more generic ones.

Re: ISR in Kinetis L

JimDon — Wed, 06 Feb 2013 19:07:33 GMT

Look in kinetis_sysinit.c.

For example, if I define " void SysTick_Handler(){}" else where, that will go in the vector table due to the weak keyword.

In ARM, a plain"C" function can be an interrupt handler, as the hardware knows that when a function returns it was from an interrupt, and how to handle it.

Re: ISR in Kinetis L

JimDon — Thu, 07 Feb 2013 02:22:53 GMT

Put this in main.c:

/*
 *  SET_NMI_INTERRUPT() - This will cause an NMI interrupt.
 *  It is a one shot, and does not need to be reset.
 */
#define SET_NMI_INTERRUPT() SCB_ICSR |= SCB_ICSR_NMIPENDSET_MASK

volatile int nmi_counter=0;
void NMI_Handler() // override the weak definition
{
  ++nmi_counter; // Put a break point here.
}

int main(int argc,char **argv) 
{  
     while(1)
       SET_NMI_INTERRUPT();
}

Re: ISR in Kinetis L

vivacious — Mon, 11 Feb 2013 01:22:35 GMT

ok...thank you one and all.

I've tested this and this works.

Well I think basic idea is that correspoinding to a IRQ function in Kinetis_sysinit.c, you have to create a function by the same name (Example UART0_IRQHandler() for UART0). The newly defined function would be the ISR for the interrut(UART0 in this case).

Let me know if I've missed anything.