clock.c

cc2430编程实例,非常适合初学者学习。

/******************************************************************************
    Filename: clock.c

    This file defines clock related functions for the CC243x family
    of RF system-on-chips from Texas Instruments.

******************************************************************************/

/*******************************************************************************
 * INCLUDES
 */

#include "clock.h"
#include <hal_mcu.h>


/*******************************************************************************
 * PUBLIC FUNCTIONS
 */


/******************************************************************************
* @fn     clockSetMainSrc
*
* @brief  Function for setting the main system clock source.
*         The function turns off the clock source that is not being used.
*         TICKSPD is set to the same frequency as the source.
*
* @param  uint8 source (one of CLOCK_SRC_HFRC or CLOCK_SRC_XOSC)
*
* @return void
*
******************************************************************************/
void clockSetMainSrc(uint8 source)
{
    register uint8 osc32k_bm = CLKCON & CLKCON_OSC32K_BM;

    // Source can have the following values:
    // CLOCK_SRC_XOSC   0x00  High speed Crystal Oscillator (XOSC)
    // CLOCK_SRC_HFRC   0x01  Low power RC Oscillator (HFRC)

    if (source == CLOCK_SRC_HFRC)
    {
        SLEEP &= ~SLEEP_OSC_PD_BM;       // power up both oscillators
        while (!CC2430_IS_HFRC_STABLE());// wait until the oscillator is stable

        asm("NOP");
        CLKCON = (osc32k_bm | CLKCON_OSC_BM | TICKSPD_DIV_2 | CLKCON_CLKSPD_BM);
        while (CLKCON != (osc32k_bm | CLKCON_OSC_BM | TICKSPD_DIV_2 | CLKCON_CLKSPD_BM));

        SLEEP |= SLEEP_OSC_PD_BM;        // power down the unused oscillator
    }
    else if (source == CLOCK_SRC_XOSC)
    {
        SLEEP &= ~SLEEP_OSC_PD_BM;       // power up both oscillators
        while (!CC2430_IS_XOSC_STABLE());// wait until the XOSC is stable

        asm("NOP");
        halMcuWaitUs(64);
        CLKCON = (osc32k_bm | TICKSPD_DIV_1);
        while (CLKCON != (osc32k_bm | TICKSPD_DIV_1));

        SLEEP |= SLEEP_OSC_PD_BM;        // power down the unused oscillator
    }

}

/******************************************************************************
* @fn     clockSelect32k
*
* @brief  Function for selecting source for the 32kHz oscillator
*
* @param  uint8 source (one of CLOCK_32K_XTAL or CLOCK_32K_RCOSC)
*
* @return void
*
******************************************************************************/
void clockSelect32k(uint8 source)
{
    if (source == CLOCK_32K_XTAL)
    {
        CLKCON &= ~CLKCON_OSC32K_BM;
    }
    else if (source == CLOCK_32K_RCOSC)
    {
        CLKCON |= CLKCON_OSC32K_BM;
    }
}

/***********************************************************************************
  Copyright 2007 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
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  YOU FURTHER ACKNOWLEDGE AND AGREE THAT THE SOFTWARE AND DOCUMENTATION ARE
  PROVIDED 揂S IS