Special features

AN3288

18/27

Doc ID 18011 Rev 2

brk_stat = TRUE;

...

}

else if(acc>thr2b) /* it corresponds to a medium braking effort */

{...

TIM1_SetCompare1(PWM2); /* set the PWM duty cycle to 50% */

brk_stat = TRUE;

...

}

...

else /* if no braking */

{TIM1_SetCompare1(PWM0); /* PWM duty cycle to 100% set LEDs OFF */

brk_stat = FALSE;

}

state= WAIT;

break;

4.2

Continuous dimming mode

The choice of the main ranges of deceleration for characterizing the light response is purely

discretionary. It's possible to set a continuous dimming mode matching the LEDs’ brightness

with the resolution of the accelerometer. Fixing a simple relation of proportionality between

the PWM duty cycle and the deceleration, according to a coefficient opportunely selected,

the LED’s brightness may vary continuously in a range of values containing more than 1,000

programmable levels.

/* PWM duty cycle proportional to the deceleration */

PWM_duty_cycle=(acc*(k));

...

if(acc< thr1)

/* if deceleration is higher than the activation

threshold */

{

...

TIM1_SetCompare1(PWM_duty_cycle); /* set the PWM duty cycle */

brk_stat = TRUE; }

...}