CCS/TMS320F280049C: GPIO qualification for rising and falling edge.

Part Number: TMS320F280049C

Tool/software: Code Composer Studio

Dear TI,

I am using a state machine to detect direction rotation(clockwise or counter clockwise) of a synchronous machine,

I am using emf voltage  phase to phase 1_2 and 2_3 comparison, the combination bellow,

10,11,01,00 for + direction   and 10, 00, 01, 11 for -.

When i test this state machine, i figured out that the state doesn't work well in low speed, 

The issue is, i want to detect rotation direction in low speed,

Do i have to activate any qualification factor for the GPIO pins?

C code

   UINT16 l_u16Ph1_2;
    UINT16 l_u16Ph2_3;
    UINT32 l_u32Test;
    int32  l_i16Dir = 0;

    l_u16Ph1_2 = GPIO_ReadPin(DRV_GPIO_X_U_COMP_PH_2_3);
    l_u16Ph2_3 = GPIO_ReadPin(DRV_GPIO_X_U_COMP_PH_1_2);

    /* memo cmp n-1*/
    l_u32Test = s_u32CmpDir;

    switch (s_u16Stat)
    {

    case 'A':
        if (1u == l_u16Ph1_2 && 0u == l_u16Ph2_3)
        {
            s_u16Stat = 'B';
            s_u32CmpDir+=10;
        }
        else if (0u == l_u16Ph1_2 && 1u == l_u16Ph2_3)
        {
            s_u16Stat = 'D';
            s_u32CmpDir-=10;
        }
        else
        {
            s_u16Stat = 'A';
        }
        break;

    case 'B':
        if (1u == l_u16Ph1_2 && 1u == l_u16Ph2_3)
        {
            s_u16Stat = 'C';
            s_u32CmpDir+=10;
        }
        else if (0u == l_u16Ph1_2 && 1u == l_u16Ph2_3)
        {
            s_u16Stat = 'A';
            s_u32CmpDir-=10;
        }
        else
        {
            s_u16Stat = 'B';
        }
        break;

    case 'C':
        if (0u == l_u16Ph1_2 && 1u == l_u16Ph2_3)
        {
            s_u16Stat = 'D';
            s_u32CmpDir+=10;
        }
        else if (1u == l_u16Ph1_2 && 0u == l_u16Ph2_3)
        {
            s_u16Stat = 'B';
            s_u32CmpDir-=10;
        }
        else
        {
            s_u16Stat = 'C';
        }

        break;

    case 'D':
        if (0u == l_u16Ph1_2 && 0u == l_u16Ph2_3)
        {
            s_u16Stat = 'A';
            s_u32CmpDir+=10;
        }
        else if (1u == l_u16Ph1_2 && 1u == l_u16Ph2_3)
        {
            s_u16Stat = 'C';
            s_u32CmpDir-=10;
        }
        else
        {
            s_u16Stat = 'D';
        }
        break;

    default:
        break;
    }

    l_i16Dir = l_u32Test - s_u32CmpDir;

    if (l_i16Dir>0)
    {
        s_u16CmpConfirm++;
    }
    else
    {
        s_u16CmpConfirm = 0;
    }

    if (s_u16CmpConfirm > 10)
    {
        *p_bRotationDir = TRUE;
    }
    else
    {
        *p_bRotationDir = FALSE;
    }

code:

Thank you in advance,

S.Tarik,