AN3288 datasheet(17/27 Pages) STMICROELECTRONICS

17 / 27 page

AN3288

Special features

Doc ID 18011 Rev 2

17/27

Regarding the two new states, while “ACTUATE_FORWARD” is implemented as the state

previously reported in the previous thresholds system C algorithm, the state

“ACTUATE_REVERSE” has been implemented in the same way but with positive threshold

values.

The thresholds system code modified for enabling the bidirectional functionality is

represented here:

/* "FORWARD" direction */

state ACTUATE_FORWARD:

if(acc<thr3a)

/* it corresponds to the maximum braking effort */

{

...

TIM1_SetCompare1(PWM3); /* set the PWM duty cycle to 25% */

brk_stat = TRUE;

...

}

else if(acc<thr2a) /* 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;

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

/* "REVERSE" direction */

state ACTUATE_REVERSE:

if(acc>thr3b)

/* it corresponds to the maximum braking effort */

{

...

TIM1_SetCompare1(PWM3); /* set the PWM duty cycle to 25% */

AN3288 Datasheet(PDF) 17 Page - STMicroelectronics