bsp.c

来自「Atmega128高档8位单片机的uCOSII移植源码工程文件」· C语言 代码 · 共 105 行

/*
*********************************************************************************************************
*                                           Atmel ATmega128
*                                         Board Support Package
*
*                                (c) Copyright 2005, Micrium, Weston, FL
*                                          All Rights Reserved
*
*
* File : BSP.C
* By   : Jean J. Labrosse
*********************************************************************************************************
*/

#include <includes.h>

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

static  void  BSP_InitTickISR(void);
static  void  LED_Init(void);

/*
*********************************************************************************************************
*                                         BSP INITIALIZATION
*
* Description : This function should be called by your application code before you make use of any of the
*               functions found in this module.
*
* Arguments   : none
*********************************************************************************************************
*/

void  BSP_Init (void)
{
    LED_Init();
    
    BSP_InitTickISR();
}


/*
*********************************************************************************************************
*                                        SETUP THE TICK RATE
*
* Note(s): 1) OCR0 = CPU_CLK_FREQ / (2 * Prescaler * OC_freq) - 1
*          2) The equation actually performs rounding by multiplying by 2, adding 1 and then divising by 2
*             in integer math, this is equivalent to adding 0.5
*********************************************************************************************************
*/

static  void  BSP_InitTickISR (void)
{
    INT32U  num;
    INT32U  denom;
    
    TCCR0  = 0x0E;                                      /* Set TIMER0 prescaler to CTC Mode, CLK/256   */
    TCNT0  =    0;                                      /* Start TCNT at 0 for a new cycle             */
    num    = (INT32U)CPU_CLK_FREQ;
    denom  = 2 * 256 * (INT32U)OS_TICKS_PER_SEC;
    OCR0   = (INT8U)((2 * num / denom + 1) / 2 - 1);
    TIFR  |= 0x02;                                      /* Clear  TIMER0 compare Interrupt Flag        */
    TIMSK |= 0x02;                                      /* Enable TIMER0 compare Interrupt             */
}


/*
*********************************************************************************************************
*                                     HANDLE THE TICK INTERRUPT
*
* Note(s): 1) No need to clear the interrupt source since we use output compare mode for Timer #0 and
*             the interrupt is automatically cleard in hardware when the ISR runs.
*********************************************************************************************************
*/

void  BSP_TickISR_Handler (void)
{
    OSTimeTick();
}


/*
*********************************************************************************************************
*                                         BSP INITIALIZATION
*
* Description : This function should be called by your application code before you make use of any of the
*               functions found in this module.
*
* Arguments   : none
*********************************************************************************************************
*/

static  void  LED_Init (void)
{
    PORTE |= LED_WORK_STATE;
    DDRE  |= LED_WORK_STATE;
}

/*********************************************************************************************************
**                            End Of File
********************************************************************************************************/