• 32位 的变量 用于表示 ms ,可以表示多少天那?


    1、在  TI  的 BLE 协议栈 中,即 OSAL 中 获取当前 系统 tick 的方法如下

     /*
      * Read the system clock - returns milliseconds
      */
      extern uint32 osal_GetSystemClock( void );

    2、32位 的变量 用于表示 ms ,可以表示多少天那?关系如下:

    2^32 ms = 

    4294967296 ms =

    4294967.296 S = 

    71582.788266666666666666666666667 分钟 = 

    1193.0464711111111111111111111111 小时 = 

    49.71026962962962962962962962963 天

    /******************************************************************************
    
     @file  OSAL_Timers.h
    
     @brief This file contains the OSAL Timer definition and manipulation functions.
    
     Group: WCS, BTS
     Target Device: CC2540, CC2541
    
     ******************************************************************************
     
     Copyright (c) 2004-2016, Texas Instruments Incorporated
     All rights reserved.
    
     IMPORTANT: Your use of this Software is limited to those specific rights
     granted under the terms of a software license agreement between the user
     who downloaded the software, his/her employer (which must be your employer)
     and Texas Instruments Incorporated (the "License"). You may not use this
     Software unless you agree to abide by the terms of the License. The License
     limits your use, and you acknowledge, that the Software may not be modified,
     copied or distributed unless embedded on a Texas Instruments microcontroller
     or used solely and exclusively in conjunction with a Texas Instruments radio
     frequency transceiver, which is integrated into your product. Other than for
     the foregoing purpose, you may not use, reproduce, copy, prepare derivative
     works of, modify, distribute, perform, display or sell this Software and/or
     its documentation for any purpose.
    
     YOU FURTHER ACKNOWLEDGE AND AGREE THAT THE SOFTWARE AND DOCUMENTATION ARE
     PROVIDED 揂S IS?WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED,
     INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY, TITLE,
     NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL
     TEXAS INSTRUMENTS OR ITS LICENSORS BE LIABLE OR OBLIGATED UNDER CONTRACT,
     NEGLIGENCE, STRICT LIABILITY, CONTRIBUTION, BREACH OF WARRANTY, OR OTHER
     LEGAL EQUITABLE THEORY ANY DIRECT OR INDIRECT DAMAGES OR EXPENSES
     INCLUDING BUT NOT LIMITED TO ANY INCIDENTAL, SPECIAL, INDIRECT, PUNITIVE
     OR CONSEQUENTIAL DAMAGES, LOST PROFITS OR LOST DATA, COST OF PROCUREMENT
     OF SUBSTITUTE GOODS, TECHNOLOGY, SERVICES, OR ANY CLAIMS BY THIRD PARTIES
     (INCLUDING BUT NOT LIMITED TO ANY DEFENSE THEREOF), OR OTHER SIMILAR COSTS.
    
     Should you have any questions regarding your right to use this Software,
     contact Texas Instruments Incorporated at www.TI.com.
    
     ******************************************************************************
     Release Name: ble_sdk_1.4.2.2
     Release Date: 2016-06-09 06:57:09
     *****************************************************************************/
    
    #ifndef OSAL_TIMERS_H
    #define OSAL_TIMERS_H
    
    #ifdef __cplusplus
    extern "C"
    {
    #endif
    
    /*********************************************************************
     * INCLUDES
     */
    
    /*********************************************************************
     * MACROS
     */
    
    /*********************************************************************
     * CONSTANTS
     * the unit is chosen such that the 320us tick equivalent can fit in 
     * 32 bits.
     */
     #define OSAL_TIMERS_MAX_TIMEOUT 0x28f5c28e /* unit is ms*/
    
    /*********************************************************************
     * TYPEDEFS
     */
    
    /*********************************************************************
     * GLOBAL VARIABLES
     */
    
    /*********************************************************************
     * FUNCTIONS
     */
    
      /*
       * Initialization for the OSAL Timer System.
       */
      extern void osalTimerInit( void );
    
      /*
       * Set a Timer
       */
      extern uint8 osal_start_timerEx( uint8 task_id, uint16 event_id, uint32 timeout_value );
      
      /*
       * Set a timer that reloads itself.
       */
      extern uint8 osal_start_reload_timer( uint8 taskID, uint16 event_id, uint32 timeout_value );
    
      /*
       * Stop a Timer
       */
      extern uint8 osal_stop_timerEx( uint8 task_id, uint16 event_id );
    
      /*
       * Get the tick count of a Timer.
       */
      extern uint32 osal_get_timeoutEx( uint8 task_id, uint16 event_id );
    
      /*
       * Simulated Timer Interrupt Service Routine
       */
    
      extern void osal_timer_ISR( void );
    
      /*
       * Adjust timer tables
       */
      extern void osal_adjust_timers( void );
    
      /*
       * Update timer tables
       */
      extern void osalTimerUpdate( uint32 updateTime );
    
      /*
       * Count active timers
       */
      extern uint8 osal_timer_num_active( void );
    
      /*
       * Set the hardware timer interrupts for sleep mode.
       * These functions should only be called in OSAL_PwrMgr.c
       */
      extern void osal_sleep_timers( void );
      extern void osal_unsleep_timers( void );
    
     /*
      * Read the system clock - returns milliseconds
      */
      extern uint32 osal_GetSystemClock( void );
    
      /*
       * Get the next OSAL timer expiration.
       * This function should only be called in OSAL_PwrMgr.c
       */
      extern uint32 osal_next_timeout( void );
    
    /*********************************************************************
    *********************************************************************/
    
    #ifdef __cplusplus
    }
    #endif
    
    #endif /* OSAL_TIMERS_H */
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  • 原文地址:https://www.cnblogs.com/suozhang/p/8611173.html
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