bsp_touchscr.c

来自「lpc2478+ucosII+ucgui源码」· C语言 代码 · 共 447 行 · 第 1/2 页

            BSP_TouchScr_Dly_uS(BSP_TOUCH_SCR_SETUP_DLY_uS);     /* Wait for I/O setup time                                    */        

        adc_acc     = 0;  
        for (i = 0; i < BSP_TOUCH_SCR_NBR_SAMPLES; i++) {
            adc_acc += BSP_ADC_GetStatus(BSP_ADC_Y1);
            BSP_TouchScr_Dly_uS(BSP_TOUCH_SCR_ADC_DLY_uS);
        }        

        adc_acc                    /= BSP_TOUCH_SCR_NBR_SAMPLES;     
        p_status->TouchScrIsPressed = DEF_TRUE;                  
        p_status->TouchScrX         = (CPU_INT16U)adc_acc;
        
    }

    BSP_TouchScr_IO_Init();                                      /* Set the I/O to a common know state                          */
}


/*
*********************************************************************************************************
*                                            BSP_TouchScr_MeasureY()
*
* Description : Measure the Y coordinate of the Touch Screen.
*               Touch Screen Hardware on the LPC2478-SK
*
*                                     (Y2) P0.21
*                                      |
*                            +---------|----------+
*                            |         |          |
*                            |      +==|==+       |
*                            |      |     |       |     
*                            |  +===============+ |       
*              P0.22  (X2)<--|--|      R1       |-|-->(X1) P0.24/AD[1]
*                            |  +===============+ |       
*                            |      | R2  |       |       
*                            |      |     |       |       
*                            |      +==|==+       |       
*                            +=========|==========+     
*                                      |
*                                     (Y1) P0.23/AD[0]
*              (1) Set Y1 and Y2 as pull-up outputs and X2 as pull-down input and X1 as ADC channel 1.
*              (2) If X2 is LOW the Touch screen is not being pressed go to step 5.
*              (3) Measure ADC Channel 1 input BSP_TOUCH_SCR_NBR_SAMPLES times.
*              (4) Average the result and return the data.
*              (5) Set Y1, Y2, X1, X2 as inputs with pull-up resistor.
*  
* Argument(s) : p_status  Pointer to the BSP_TOUCH_SCR_STATUS structure.                   
*
* Return(s)   : none.
*
* Caller(s)   : Application
*               
* Note(s)     : none.
*********************************************************************************************************
*/

void  BSP_TouchScr_MeasureY (BSP_TOUCH_SCR_STATUS  *p_status)
{
    CPU_INT32U   adc_acc;
    CPU_INT32U   i;
    
    
    IO0DIR   |= BSP_TOUCH_SCR_IO0DIR_Y_GRP;                      /* Configure Y1 and Y2 as outputs                             */
    IO0SET    = BSP_TOUCH_SCR_IO0DIR_Y_GRP;                      /* Set Y1 and Y2 to '1'                                       */
    PINSEL1  |= BSP_TOUCH_SCR_PINSEL1_X1_ADC;                    /* Select X1 as ADC channel 1                                 */
    PINMODE1 |= BSP_TOUCH_SCR_PINMODE1_X2_PULL_DOWN;             /* Configure X2 with a Pull-Down resistor                     */
    
    
    BSP_TouchScr_Dly_uS(BSP_TOUCH_SCR_SETUP_DLY_uS);             /* Wait for I/O Setup time                                    */
    
    if (DEF_BIT_IS_CLR(IO0PIN, BSP_TOUCH_SCR_IO0DIR_X2)) {       /* If X2 is LOW the Touch Screen is not being pressed         */
        p_status->TouchScrIsPressed = DEF_FALSE;
    } else {                                                     /* If X2 is HIGH the Touch Screen is being pressed            */
        IO0CLR  = BSP_TOUCH_SCR_IO0DIR_Y2;                       /* Reset Y2 to '0' so current will drain between Y1->Y2       */
       BSP_TouchScr_Dly_uS(BSP_TOUCH_SCR_SETUP_DLY_uS);          /* Wait for I/O setup time                                    */        
        
        adc_acc     = 0;  
        
        for (i = 0; i < BSP_TOUCH_SCR_NBR_SAMPLES; i++) {           
            adc_acc += BSP_ADC_GetStatus(BSP_ADC_X1);
            BSP_TouchScr_Dly_uS(BSP_TOUCH_SCR_ADC_DLY_uS);
        }        
        
        adc_acc                    /= BSP_TOUCH_SCR_NBR_SAMPLES; /* Average the ADC samples result                              */  
        p_status->TouchScrIsPressed = DEF_TRUE;                  
        p_status->TouchScrY         = (CPU_INT16U)adc_acc;
        
    }

    BSP_TouchScr_IO_Init();                                      /* Set the I/O to a common know state                          */
}



/*
*********************************************************************************************************
*                                            BSP_TouchScr_Convert()
*
* Description : Convert the X and Y coordenates form ADC value to Pixels value. 
*               Touch Screen Hardware on the LPC2478-SK
*
*                                  (Y2) P0.21
*                            |--- 320 (pixels) ---|
*                            +---------|----------+ -----
*                            |         |          |     |
*                            |      +==|==+       |     |
*                            |      |     |       |     | (240 pixels)   
*                            |  +===============+ |     |  
*              P0.22  (X2)<--|--|      R1       |-|-->(X1) P0.24/AD[1]
*                            |  +===============+ |     |  
*                            |      | R2  |       |     |  
*                            |      |     |       |     |  
*                            |      +==|==+       |     |  
*                            +=========|==========+ ----|    
*                                      |
*                                     (Y1) P0.23/AD[0]
*  
* Argument(s) : p_status  Pointer to the BSP_TOUCH_SCR_STATUS structure.                   
*
* Return(s)   : none.
*
* Caller(s)   : Application
*               
* Note(s)     : none.
*********************************************************************************************************
*/

void  BSP_TouchScr_Convert (BSP_TOUCH_SCR_STATUS  *p_status)
{
    CPU_INT32U  x_pixels;
    CPU_INT32U  y_pixels;

    
    x_pixels  = (p_status->TouchScrX - BSP_TOUCH_SCR_MIN_X_ADC) 
              * (BSP_TOUCH_SCR_H_SIZE);
    x_pixels /= (BSP_TOUCH_SCR_DELTA_X_ADC); 
    
    y_pixels  = (BSP_TOUCH_SCR_MAX_Y_ADC - p_status->TouchScrY) 
              * BSP_TOUCH_SCR_V_SIZE;

    y_pixels /= (BSP_TOUCH_SCR_DELTA_Y_ADC); 
    
    p_status->TouchScrX = x_pixels;
    p_status->TouchScrY = y_pixels;
}

/*
*********************************************************************************************************
*                                              BSP_TouchScr_Dly()
*
* Description : Delay for the specified number of micro seconds
*               
* Argument(s) : us  number of microseconds to delay.
*
* Return(s)   : none.
*
* Caller(s)   : BSP_TouchScr_MeasureX()
*               BSP_TouchScr_MeasureY()
*
* Note(s)     : none.
*********************************************************************************************************
*/

static void  BSP_TouchScr_Dly_uS (CPU_INT32U  us) 
{   
    CPU_INT32U  pclk_freq;
    CPU_INT32U  cpu_freq;
    CPU_INT32U  tmr_dly;
    CPU_INT32U  dflt_dly;
   
    
    pclk_freq = BSP_CPU_PclkFreq(BSP_PCLK_TIMER3);
    cpu_freq  = BSP_CPU_ClkFreq();
    tmr_dly   = (pclk_freq / 1000000L) *  us ;
    dflt_dly  = (cpu_freq  / 1000000L) *  BSP_TOUCH_SCR_DFLT_DLY_uS;
    
    T3TCR     = 2;                                              /* Disable timer 0 and reset.                                */
    T3PC      = 0;                                              /* Prescaler is set to no division.                          */
    T3CCR     = 0;                                              /* Capture is disabled.                                      */
    T3EMR     = 0;                                              /* No external match output.                                 */
    T3TCR     = 1;                                              /* Enable timer 0                                            */
    
    while (((CPU_INT32U)T3TC     < tmr_dly) &&                  /* If the Timer is stopped by the application the default... */
            (CPU_INT32U)dflt_dly > 0      ) {                   /* delay counter is used.                                    */                          
        dflt_dly--;
    }
   
}  

/*
*********************************************************************************************************
*                                             BSP_TouchScr_IO_Init()
*
* Description : Initializes the Touch Screen I/Os as inputs with Pull-Up resistor
*               
* Argument(s) : none.
*
* Return(s)   : none.
*
* Caller(s)   : BSP_TouchScr_Init()
*               BSP_TouchScr_MeasureX()
*               BSP_TouchScr_MeasureY()
*
* Note(s)     : (1) In order to save power while a conversion is not required the Touch Screen I/O are set to
                    inputs with a pull-up resistor.
*********************************************************************************************************
*/

static void  BSP_TouchScr_IO_Init (void)
{
    IO0DIR   &= ~(BSP_TOUCH_SCR_IO0DIR_Y_GRP
              |   BSP_TOUCH_SCR_IO0DIR_X_GRP);
    
    PINSEL1  &= ~(BSP_TOUCH_SCR_PINSEL1_X1_MASK
              |   BSP_TOUCH_SCR_PINSEL1_X2_MASK 
              |   BSP_TOUCH_SCR_PINSEL1_Y1_MASK 
              |   BSP_TOUCH_SCR_PINSEL1_Y2_MASK); 

    PINMODE1 &= ~(BSP_TOUCH_SCR_PINMODE1_X1_MASK
              |   BSP_TOUCH_SCR_PINMODE1_X2_MASK 
              |   BSP_TOUCH_SCR_PINMODE1_Y1_MASK
              |   BSP_TOUCH_SCR_PINMODE1_Y2_MASK);     
}