FRDM KE06Z: How to access Interrupt service program?

[scofieldwolff]

Hi, I just use Kinetis E series MCU. And use GPIO_demo code to test my board, I wanna use Interrupt service program to light LED for 1Hz. But never access the Interrupt service program, I check the demo program, and set NVIC_ISER  and RTC_RTIE, this 's OK.   However, dont using interrput program to lingt LED, and polling RTIF flag code is OK.

I dont kown how to access interrupt service program,   THX  for your Help.

[isaacavila · Accepted solution]

Hi Scofield,

When using an Interrupt Service Routine (ISR) you have to consider next conditions:

• When Configuring your Peripheral (In my case I will use PIT_CH0 as Interrupt source) you have to set the right flags to request an interrupt:

• Then, you must enable its respective vector in the NVIC module. This steps consists to write to specific ISER register and set its priority:

As you can see on Interrupt Vector Assignments table on MCU’s reference manual, PIT_CH0 vector is expressed as 38, however, when enable this vector on NVIC module, we must select IRQ value (38 – 16 = 22; It subtracts 16 because the first 16 vectors are core-vectors.)

• After NVIC configuration is done, We must enable all interrupts in the core, this is done by using the assembler instruction:  CPSIE i:

/* Enable interrupts (clear PRIMASK) */

#define ENABLE_INTERRUPTS  asm(" CPSIE i");

• Then, we must implement our ISR. In this ISR we must clear the specific flag that causes the interrupt request.

void PIT_CH0_IRQHandler(void) {

    /* Clear Timer Interrupt Flag */

    PIT_TFLG0 |= PIT_TFLG_TIF_MASK;

    /* Do your ISR proccess here */

}

• At this point, how does the MCU knows that PIT_CH0_IRQHanlder corresponds to PIT0? Well, there is a table located at: Project_Settings > Startup_Code > kinetis_sysinit.c (for CodeWarrior 10.6 and bare metal project)

• In this source file, there is a table where all ISR are declared, so make sure your ISR is named exactly the same as in InterruptVector table:

• After following these steps you shouldn’t have any problems on attending the specific ISR.

I attached the project (It was done using a KE04 board) but hope this could serve as example.

Regards,

Isaac Avila

[scofieldwolff]

Thanks, I solve the problem. I set RTC interrupt exactly, but I forgot to set my ISR code to the interrupt vector.   However, I take a Macro for linking my interrupt service code to interrupt vector. In the interrupt souce file, I do it as follow.

#ifndefine RTC_IRQHandler

#define RTC_IRQHandler  RTC_Isr  // RTC-Isr is my interrupt code.

extern void RTC_Isr(void);

Before making  the Macro ,  I comment the RTC_IRQHandler Func. declaration.

[Alice_Yang]

Hello scofield,

I recommend you firstly refer to a GPIO interrupt demo code  .

And which IDE do you use ? If CW , please refer to here :

  ....\Freescale\CW MCU v10.6\MCU\CodeWarrior_Examples\Kinetis_Examples\KE\build\cw\ke06\GPIO_demo

If you do not use this , i attachment the main file , i think you can refer to .

If you have some question about this demo , you can tell me !

Have a great day,
Alice

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[scofieldwolff]

Thanks for your help. I conquer the problem.I forgot to set the Interrupt vector.