Microbalze becomes weird

[xuantran]

Dear all,

I have a Microblaze, which blinks a LED by using for loop delay with DELAY being 10000.

Clock of the Microblaze is 100MHz.

Optimization level of an application is -O0.

With this setup, I can see clearly the blinking LED .

However, when the Microblaze uses a Timer to measure eslapsed time of the for loop. I cannot see the blinking LED anymore. Actually, in this case the LED blinks faster than in the case without the Timer. In oder to see the blinking LED, I changed the DELAY of the for loop to 1000000.

I did an another experiment on the Evaluation Board VC709. The setup is the same as the one I did before. Nevertheless, I only see the blinking LED with the DELAY of the for loop being 1000000. With the DELAY being 10000, I cannot see the blinking LED.

Could you explain why it happens like this? What did I do wrongly?

I would be grateful for any help.

[bpatterson]

It would probably be helpful if you could post your code / block design.

[xuantran]

Thank you so much for your suggestion.

I attach the snapshop of the block desgin. The code is below.

* main.c

/****************************************************************************/
/* Includes */
#include "xparameters.h"
#include "xstatus.h"

#include "gpio.h"
#include "xtmrctr.h"

/****************************************************************************/
#define GPIO_LED_DEVICE_ID XPAR_GRNCB_UB_MAIN_GRNCB_UB_AXI_GPIO_0_BASEADDR
#define TMRCTR_DEVICE_ID XPAR_TMRCTR_0_DEVICE_ID

#define TIMER_COUNTER_0 0

/* The AXI GPIO is connected to a tri color LED. This LED can light up into two
* different colors: green and red. */
static const uint32_t LED_GREEN = 0;// Bit 0 of GPIO is connected to the green LED
static const uint32_t LED_RED = 1; // Bit 1 of GPIO is connected to the red LED
static const uint32_t LED_DELAY = 10000;
/****************************************************************************/

/* Variable Definitions */
static XGpio gpioLEDInst; /* The instance of the GPIO */

static XTmrCtr TimerCounter; /* The instance of the Tmrctr Device */

/****************************************************************************/
static int32_t mainInit ();

/****************************************************************************/

int main()
{
int32_t status = XST_FAILURE;
volatile uint32_t i = 0;
uint32_t initTimerVal = 0;
uint32_t currTimerVal = 0;
uint32_t diffTimerVal = 0;

status = mainInit();
if (XST_SUCCESS != status)
return XST_FAILURE;

/* Start the timer */
XTmrCtr_Start(&TimerCounter, TIMER_COUNTER_0);

while(1)
{
gpioLEDOn (&gpioLEDInst, LED_GREEN); // Turn on LED
initTimerVal = XTmrCtr_GetValue (&TimerCounter, TIMER_COUNTER_0);
for (i = 0; i < LED_DELAY; ++i); // Delay

currTimerVal = XTmrCtr_GetValue (&TimerCounter, TIMER_COUNTER_0);

diffTimerVal = currTimerVal - initTimerVal;

gpioLEDOff (&gpioLEDInst, LED_GREEN); // Turn off LED
for (i = 0; i < LED_DELAY; ++i) {} // Delay
gpioLEDOn (&gpioLEDInst, LED_RED); // Turn on LED
for (i = 0; i < LED_DELAY; ++i) {} // Delay
gpioLEDOff (&gpioLEDInst, LED_RED); // Turn off LED
for (i = 0; i < LED_DELAY; ++i){} // Delay
}
/*
* Disable the Autoreload mode of the timer counters.
*/
XTmrCtr_SetOptions(&TimerCounter, TIMER_COUNTER_0, 0);

return 0;
}

/****************************************************************************/
static int32_t mainInit ()
{
int32_t status = XST_FAILURE;

/* Initialize GPIO (LEDs) */
status = gpioLEDInit (&gpioLEDInst, GPIO_LED_DEVICE_ID);
if (XST_SUCCESS != status)
return XST_FAILURE;

/* Initialize Timer */
status = tmrCntInit (&TimerCounter, TMRCTR_DEVICE_ID, TIMER_COUNTER_0);
if (XST_SUCCESS != status)
{
return XST_FAILURE;
}

return status;
}
/****************************************************************************/

Please let me know if there is anything missing or unclear.

[peters]

Hi Xuan,

One thing I noticed is the line in your your C-code:

#define GPIO_LED_DEVICE_ID XPAR_GRNCB_UB_MAIN_GRNCB_UB_AXI_GPIO_0_BASEADDR

You assign a Baseaddress to a device ID which doesn’t look right for me.

The device ID is an assigned number to an instance of axi_gpio (can be seen in the xparameters.h), whereas the Baseaddress is actually an address in your address map.

Please check if this could be the problem.

[xuantran]

You are right. Thank you so much for pointing out my mistake.

#define GPIO_LED_DEVICE_ID XPAR_GRNCB_UB_MAIN_GRNCB_UB_AXI_GPIO_0_BASEADDR

XPAR_GRNCB_UB_MAIN_GRNCB_UB_AXI_GPIO_0_BASEADDR = 0x40000000

Unfortunately , the software still finds the device beacause the DeviceId is uint16_t. :-(

int32_t gpioLEDInit (XGpio *InstancePtr, uint16_t DeviceId)