Out of memory?

hitsumen · ‎2012-05-13

Posted on May 13, 2012 at 18:30

Good day,

I was playing with ST32F103RET6 MCU.

I looked in datasheet, my MCU has 64Kb of SRAM, so I could easily create array with 20 kbytes. But I cannot.

I use IAR compiler, What can be wrong. I can create only 1800byte array.

unsigned char my_array[1800];

If I create something like my_array[3000]. My MCU going to reset..

Thank you.

#ram #linker-error

frankmeyer9 · ‎2012-05-18

Posted on May 18, 2012 at 10:22

Do you access this array from two different places, say, from main loop and from within an interrupt ?

Then you might have a synchronization problem. The pictures look like something is advancing your array indices 'randomly' in the loop, judging the code you provided.

hitsumen · ‎2012-05-20

Posted on May 20, 2012 at 16:17

Its weird, I removed transfer to UART, and changed to transfer directly to LCD and it worked, hmm, but still something is not right.. I think something is wrong with interupts.. I will post my interupt functions when I get home, maybe you will find something strange there.

I think that when I do some processing, interupt handler could interupt the sending process, and something weird is happening..

hitsumen · ‎2012-05-20

Posted on May 20, 2012 at 16:21

Yes I think the same thing.. I will post some code, maybe you see what is wrong here.. And I tried to disable global interupts, it does not worked, it looked something like this:

asm volatile (''cpsid i'');

frankmeyer9 · ‎2012-05-20

Posted on May 20, 2012 at 19:23

I guess your ''threads'' (to steal this terminus from PC programming) are not properly synchronized. Interrupts, especially communication related ones, have a lot in common with threads/processes. The synchronization and safe communication between those threads is a nontrivial problem - I believe you know those issues like race conditions & deadlocks...

If you have a logic analyzer available, you can use some free GPIOs as debug outputs to trace the issue down under realtime conditions.

hitsumen · ‎2012-05-20

Posted on May 20, 2012 at 20:46

some code:

#define GPIO_VSYNC_CMOS GPIOC

#define RCC_APB2Periph_GPIO_VSYNC_CMOS RCC_APB2Periph_GPIOC

#define GPIO_PIN_VSYNC_CMOS GPIO_Pin_4

#define EXTI_LINE_VSYNC_CMOS EXTI_Line4

#define GPIO_PORT_SOURCE_VSYNC_CMOS GPIO_PortSourceGPIOC

#define GPIO_PIN_SOURCE_VSYNC_CMOS GPIO_PinSource4

void ov7670_Interrupts_Config_EN(void)

{

NVIC_InitTypeDef NVIC_InitStructure;

#ifdef VECT_TAB_RAM

/* Set the Vector Table base location at 0x20000000 */

NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);

#else /* VECT_TAB_FLASH */

/* Set the Vector Table base location at 0x08000000 */

NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);

#endif

/* Configure one bit for preemption priority */

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);

/* Configure one bit for preemption priority */

NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

/* Enable the EXTI9_5 Interrupt */

NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQChannel;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

}

void OV7670_EXTI_Config_EN(void)

{

EXTI_InitTypeDef EXTI_InitStructure;

GPIO_EXTILineConfig(GPIO_PORT_SOURCE_VSYNC_CMOS, GPIO_PIN_SOURCE_VSYNC_CMOS);

EXTI_InitStructure.EXTI_Line = EXTI_LINE_VSYNC_CMOS;

EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;

EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising ;

EXTI_InitStructure.EXTI_LineCmd = ENABLE;

EXTI_Init(&EXTI_InitStructure);

EXTI_GenerateSWInterrupt(EXTI_LINE_VSYNC_CMOS);

}