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FRDM KE06Z: How to access Interrupt service program?

Question asked by scofield wolff on May 20, 2015
Latest reply on May 27, 2015 by scofield wolff

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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

May 28, 2015 8:41 AM

Correct Answer

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

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Alice_Yang

May 22, 2015 1:42 AM

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

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scofield wolff @ Alice_Yang on May 28, 2015 7:18 AM

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

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isaacavila

May 28, 2015 8:41 AM

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:

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

Attachments

KE_04_Interrupt_Handling.zip187.8 KB

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scofield wolff @ isaacavila on May 28, 2015 7:18 AM

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.

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4 Replies

Alice_Yang May 22, 2015 1:42 AM
Mark Correct
Correct Answer
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!
-----------------------------------------------------------------------------------------------------------------------
Attachments
- isr.h.zip967 bytes
- readme.txt.zip1.0 KB
- GPIO_demo.c.zip1.4 KB
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- scofield wolff @ Alice_Yang on May 28, 2015 7:18 AM
  Mark Correct
  Correct Answer
  Thanks for your help. I conquer the problem.I forgot to set the Interrupt vector.
  Like • Show 0 Likes0
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isaacavila May 28, 2015 8:41 AM
Unmark Correct
Correct Answer
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
Attachments
- KE_04_Interrupt_Handling.zip187.8 KB
Like • Show 0 Likes0
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- scofield wolff @ isaacavila on May 28, 2015 7:18 AM
  Mark Correct
  Correct Answer
  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.
  Like • Show 0 Likes0
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FRDM KE06Z: How to access Interrupt service program?

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