Pwm modulation on blackfin

Hi All
I'm trying to modulate PWM timer (working on 1MHz) with sinusoidal signal at 50 Hz on Blackfin 537.
the VI working done, but i'm cannot control the frequency on modulating signal, however it's look like the FOR loop proccesing time is 1.7msec. why ?
My software: Labview 8.6 , ADI_Blackfin 8.6
Hardware : ADSP-BF537 EZ-KIT, silicone ver 0.2
Attachments:
pwm_modulation.JPG ‏79 KB

Hi Karunya,
I'm downloaded the datasheet of ADSP-BF537 EZ-KIT. From that I'm understand that I'm can't work with TMR0 and LED4 in the same project.
What I'm mean in my question is why I'm see the signal that generated to TMR0 only on LED4, and not between pins 6 and 9 on header P11. The signal was checked by oscilloscope.
Following your request to measure the execution time of FOR loop by using flat sequence and timer, I can't do it because in working with BlackFin, labview compiling the VI and downloaded him to the RAM of EZ-KIT, and the VI looking like freeze (not on running mode) and I'm doesn't see any change on indicators. To demonstrate this operation, I'm measure the time of steps on one cycle of output signal. Attached image from oscilloscope, you can see that the time of one step (is equal to one iteration of FOR loop) is around 1.7 msec.
My main question is how to increase the iteration cycle of executed FOR loop, or any other suggestion to create modulated PWM by sinusoidal signal with adjustable frequency of sinusoidal signal (at range of 10-100Hz).
Note: my mission is to create modulated PWM, when carrier signal on 100kHz (natural frequency of TMR0) and modulated by signal (that change the % of duty cycle for TMR0) is absolute sinusoidal at range of 10-100Hz (because the % of duty cycle can be 0-100%).
The absolute sinus that you see on the image got from Low Pass filter by the oscilloscope software.
Attachments:
Block diagram 10 sample.JPG ‏88 KB
pwm_10samples.JPG ‏28 KB
pwm_100samples.JPG ‏27 KB

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I am just posting my last trouble when I was using Labview software for an academic work.
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National Instruments France
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