bsp.c

keil 下的ucOS移植程序。移植平台AT91SAM7S64.

/*
*********************************************************************************************************
*                                            Atmel AT91 SAM7
*                                         Board Support Package
*
*                              (c) Copyright 2004, Micrium, Inc., Weston, FL
*                                          All Rights Reserved
*
*
* File : BSP.C
* By   : Jean J. Labrosse
*********************************************************************************************************
*/

#include <includes.h>
/*
*********************************************************************************************************
*                                              CONSTANTS
*********************************************************************************************************
*/


/*
*********************************************************************************************************
*                                              PROTOTYPES
*********************************************************************************************************
*/

static  void  BSP_DummyISR_Handler(void);
static  void  Tmr_TickISR_Handler(void);


/*
*********************************************************************************************************
*                                           DUMMY IRQ HANDLER
*
* Description : This function is called to handle invalid IRQs
*
* Arguments   : none
*********************************************************************************************************
*/

static  void  BSP_DummyISR_Handler (void)
{
}

/*
*********************************************************************************************************
*                                    INITIALIZE THE INTERRUPT CONTROLLER
*
* Description : This function is called to disable ALL interrupts.
*
* Arguments   : none
*********************************************************************************************************
*/

void  BSP_IntCtrlInit (void)
{
    int  i;

    AT91C_BASE_AIC->AIC_EOICR = 0x00000000;                        /* End-of-interrupt command         */

    for (i = 0; i < 32; i++) {                                     /* Disable all ISRs                 */
        AT91C_BASE_AIC->AIC_SVR[i] = (INT32U)BSP_DummyISR_Handler;
        AT91C_BASE_AIC->AIC_SMR[i] = 0;
    }
}


/*
*********************************************************************************************************
*                                         TICKER INITIALIZATION
*
* Description : This function is called to initialize uC/OS-II's tick source which uses the PIT
*               (typically a timer generating interrupts every 1 to 100 mS).
*
* Arguments   : none
*
* Note(s)     : 1) PIT Interrupt frequency:
*
*                         MCLK        1
*               Freq =    ---- * -----------
*                          16     (PIV + 1)
*
*
*                         MCLK      1
*               PIV  =  ( ---- * ------ ) - 1
*                          16     Freq
*
*               Where:
*                    MCLK = 48 MHz (i.e 48,000,000)
*                    Freq = Desired frequency (i.e. OS_TICKS_PER_SEC)
*********************************************************************************************************
*/

void  Tmr_TickInit (void)
{
    INT32U  counts;

                                                /* Set the vector address for PIT                      */
    AT91C_BASE_AIC->AIC_SVR[AT91C_ID_SYS] = (INT32U)Tmr_TickISR_Handler;
    AT91C_BASE_AIC->AIC_SMR[AT91C_ID_SYS] = AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE
                                          | AT91C_AIC_PRIOR_LOWEST;

    // clear any pending interrupt for this AIC input and then enable the interrupt.
    AT91C_BASE_AIC->AIC_ICCR              = 1 << AT91C_ID_SYS;
    AT91C_BASE_AIC->AIC_IECR              = 1 << AT91C_ID_SYS;

    counts                                = (48000000 / 16 / OS_TICKS_PER_SEC) - 1;
    AT91C_BASE_PITC->PITC_PIMR            = AT91C_PITC_PITEN | AT91C_PITC_PITIEN | counts;
}


/*
*********************************************************************************************************
*                                           PIT IRQ HANDLER
*
* Description : This function handles the PIT interrupt that is used to generate TICKs for uC/OS-II.
*
* Arguments   : none
*********************************************************************************************************
*/

static  void  Tmr_TickISR_Handler (void)
{
    volatile  INT32U  status;


    if (AT91C_BASE_PITC->PITC_PISR & AT91C_PITC_PITS)
    {
      status = AT91C_BASE_PITC->PITC_PIVR;      /* Clear PIT interrupt                                   */

      OSTimeTick();                             /* Tell uC/OS-II about clock tick                        */
    }
}