STM CircleOS forum / Using interrupts with CircleOS V1.6

Squonk · 2007-10-28 13:08:09

How can I use a hardware interrupt with CircleOS V1.6. Since the vector table is now in RAM this should be possible. Does anybody have a code snipplet for adjusting the interrupt vector?

Regards

Squonk

lionel · 2007-10-28 14:34:36

Hello,

the functions to use are :

Code:

void UTIL_SetIrqHandler (int it_number, tHandler it_routine);
tHandler* UTIL_GetIrqHandler (int it_number);

Here is a snippet of Application.c from the PrimerMouse application (it makes use of USB interrupts):

Code:

[...]
tHandler OldHandler;

enum MENU_code Application_Ini ( void )
   {
   [...]
#define ID_IRQ_USB_LP  (0x90)
      
   //Set IRQ Handler
   OldHandler = (tHandler)UTIL_GetIrqHandler( ID_IRQ_USB_LP );
   UTIL_SetIrqHandler(ID_IRQ_USB_LP, (u32)USB_Istr);

   //USB Initialization
   Set_System();  
   USB_Interrupts_Config();
   Set_USBClock();
   USB_Init();
   [...]
   }

regards,
Lionel

Squonk · 2007-10-28 21:22:42

Thank You for the very useful information. I guess I should have taken a look into the PrimerMouse Apllication sources earlier!
But another question: Which interupts are used by the CircleOS and which can be used freely by my own application? Is there any hint for this in the documentation, or must I examine the source code of CircleOS?
Best regards
Squonk

Francis · 2007-10-29 08:04:50

CircleOS uses the systick (scheduler) and the timer2 interupts (to perform the MEMS sampling at a constant rate).

armaniake · 2008-06-17 00:00:13

Hi,

What is the rate at which the MEMS is polled at the maximum CPU speed (72Mhz) - Circle_OS1.7?

I understand that TIMER2 calls MEMS_Handler() regularly via interrupt.

It seems that the PCLK1 clock (TIMER 2 CLK) is at 72MHz. I say so because of the x2Multiplier that kicks in when APB1 prescaler is set to a different value than 1. It is the case here as we have:

RCC_Configuration()

/* PCLK1 = HCLK/2 */
RCC_PCLK1Config( RCC_HCLK_Div2 );

And from

TIM_Configuration(),

it looks like we setup TIMER 2 for a rate of:

512 * (1/72000000) = 7.1us (140KHz)

Note: MEMS_DIVIDER is set to 1 in MEMS_Handler()

It seems as we were polling the MEMS at 140KHz but that does not make sense as the max ODR = 2560Hz (ODR4, 640Hz).

What am I missing?

Francis · 2008-06-17 18:38:44

The pre-division by 256 in the timer.
The max frequency is 140kHz/256 = 546Hz.

armaniake · 2008-06-17 19:29:08

I see,

I suppose it is done by

TIM_Configuration()

...

/* Immediate load of TIM2 Precaler value */
TIM_PrescalerConfig( TIM2, 0x100, TIM_PSCReloadMode_Immediate );

I missed that point as I am still trying to get a grasp on how to configure the timer for a time base mechanism. Particularly, I'm not sure of what is the difference between:

TIM_TimeBaseStructure.TIM_Prescaler = 0x1;

and

TIM_PrescalerConfig( TIM2, 0x100, TIM_PSCReloadMode_Immediate );

They both seem to hit the TIM2PSC register. Would know a bit more than maybe to tell me what is the distinction between those?

Thank you

Francis · 2008-06-18 12:25:20

You are right, the second line seems to overwrite the initial configuration. It will be removed in V1.8 (and replaced by a proper initial (single) configuration).

# 1 2007-10-28 13:08:09 Using interrupts with CircleOS V1.6

Using interrupts with CircleOS V1.6

# 2 2007-10-28 14:34:36 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

Code:

Code:

# 3 2007-10-28 21:22:42 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

# 4 2007-10-29 08:04:50 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

# 5 2008-06-17 00:00:13 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

# 6 2008-06-17 18:38:44 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

# 7 2008-06-17 19:29:08 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

# 8 2008-06-18 12:25:20 Using interrupts with CircleOS V1.6

Re: Using interrupts with CircleOS V1.6

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