versions/v1_4_0/mynewt-core/hw/mcu/nxp/mkw41z/src/system_MKW41Z4.c

/*
** ###################################################################
**     Processors:          MKW41Z256VHT4
**                          MKW41Z512VHT4
**
**     Compilers:           Keil ARM C/C++ Compiler
**                          GNU C Compiler
**                          IAR ANSI C/C++ Compiler for ARM
**
**     Reference manual:    MKW41Z512RM Rev. 0.1, 04/2016
**     Version:             rev. 1.0, 2015-09-23
**     Build:               b160720
**
**     Abstract:
**         Provides a system configuration function and a global variable that
**         contains the system frequency. It configures the device and initializes
**         the oscillator (PLL) that is part of the microcontroller device.
**
**     Copyright (c) 2016 Freescale Semiconductor, Inc.
**     All rights reserved.
**
**     Redistribution and use in source and binary forms, with or without modification,
**     are permitted provided that the following conditions are met:
**
**     o Redistributions of source code must retain the above copyright notice, this list
**       of conditions and the following disclaimer.
**
**     o Redistributions in binary form must reproduce the above copyright notice, this
**       list of conditions and the following disclaimer in the documentation and/or
**       other materials provided with the distribution.
**
**     o Neither the name of Freescale Semiconductor, Inc. nor the names of its
**       contributors may be used to endorse or promote products derived from this
**       software without specific prior written permission.
**
**     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
**     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
**     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
**     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
**     ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
**     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
**     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
**     ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
**     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
**     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**
**     http:                 www.freescale.com
**     mail:                 support@freescale.com
**
**     Revisions:
**     - rev. 1.0 (2015-09-23)
**         Initial version.
**
** ###################################################################
*/

/*!
 * @file MKW41Z4
 * @version 1.0
 * @date 2015-09-23
 * @brief Device specific configuration file for MKW41Z4 (implementation file)
 *
 * Provides a system configuration function and a global variable that contains
 * the system frequency. It configures the device and initializes the oscillator
 * (PLL) that is part of the microcontroller device.
 */

#include <stdint.h>
#include "mcu/fsl_device_registers.h"
#include "mcu/cmsis_nvic.h"

/* ----------------------------------------------------------------------------
   -- Core clock
   ---------------------------------------------------------------------------- */

uint32_t SystemCoreClock = DEFAULT_SYSTEM_CLOCK;

/* ----------------------------------------------------------------------------
   -- SystemInit()
   ---------------------------------------------------------------------------- */

void SystemInit (void) {

#if (DISABLE_WDOG)
  /* SIM_COPC: COPT=0,COPCLKS=0,COPW=0 */
  SIM->COPC = (uint32_t)0x00u;
#endif /* (DISABLE_WDOG) */

  NVIC_Relocate();
}

/* ----------------------------------------------------------------------------
   -- SystemCoreClockUpdate()
   ---------------------------------------------------------------------------- */

void SystemCoreClockUpdate (void) {

  uint32_t MCGOUTClock;                /* Variable to store output clock frequency of the MCG module */
  uint16_t Divider;

  if ((MCG->C1 & MCG_C1_CLKS_MASK) == 0x00U) {
    /* FLL is selected */
    if ((MCG->C1 & MCG_C1_IREFS_MASK) == 0x00U) {
      /* External reference clock is selected */
      if((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x00U) {
        MCGOUTClock = CPU_XTAL_CLK_HZ; /* System oscillator drives MCG clock */
      } else {
        MCGOUTClock = CPU_XTAL32k_CLK_HZ; /* RTC 32 kHz oscillator drives MCG clock */
      }
      if (((MCG->C2 & MCG_C2_RANGE_MASK) != 0x00U) && ((MCG->C7 & MCG_C7_OSCSEL_MASK) != 0x01U)) {
        switch (MCG->C1 & MCG_C1_FRDIV_MASK) {
        case 0x38U:
          Divider = 1536U;
          break;
        case 0x30U:
          Divider = 1280U;
          break;
        default:
          Divider = (uint16_t)(32LU << ((MCG->C1 & MCG_C1_FRDIV_MASK) >> MCG_C1_FRDIV_SHIFT));
          break;
        }
      } else {/* ((MCG->C2 & MCG_C2_RANGE_MASK) != 0x00U) */
        Divider = (uint16_t)(1LU << ((MCG->C1 & MCG_C1_FRDIV_MASK) >> MCG_C1_FRDIV_SHIFT));
      }
      MCGOUTClock = (MCGOUTClock / Divider); /* Calculate the divided FLL reference clock */
    } else { /* (!((MCG->C1 & MCG_C1_IREFS_MASK) == 0x00U)) */
      MCGOUTClock = CPU_INT_SLOW_CLK_HZ; /* The slow internal reference clock is selected */
    } /* (!((MCG->C1 & MCG_C1_IREFS_MASK) == 0x00U)) */
    /* Select correct multiplier to calculate the MCG output clock  */
    switch (MCG->C4 & (MCG_C4_DMX32_MASK | MCG_C4_DRST_DRS_MASK)) {
      case 0x00U:
        MCGOUTClock *= 640U;
        break;
      case 0x20U:
        MCGOUTClock *= 1280U;
        break;
      case 0x40U:
        MCGOUTClock *= 1920U;
        break;
      case 0x60U:
        MCGOUTClock *= 2560U;
        break;
      case 0x80U:
        MCGOUTClock *= 732U;
        break;
      case 0xA0U:
        MCGOUTClock *= 1464U;
        break;
      case 0xC0U:
        MCGOUTClock *= 2197U;
        break;
      case 0xE0U:
        MCGOUTClock *= 2929U;
        break;
      default:
        break;
    }
  } else if ((MCG->C1 & MCG_C1_CLKS_MASK) == 0x40U) {
    /* Internal reference clock is selected */
    if ((MCG->C2 & MCG_C2_IRCS_MASK) == 0x00U) {
      MCGOUTClock = CPU_INT_SLOW_CLK_HZ; /* Slow internal reference clock selected */
    } else { /* (!((MCG->C2 & MCG_C2_IRCS_MASK) == 0x00U)) */
      Divider = (uint16_t)(0x01LU << ((MCG->SC & MCG_SC_FCRDIV_MASK) >> MCG_SC_FCRDIV_SHIFT));
      MCGOUTClock = (uint32_t) (CPU_INT_FAST_CLK_HZ / Divider); /* Fast internal reference clock selected */
    } /* (!((MCG->C2 & MCG_C2_IRCS_MASK) == 0x00U)) */
  } else if ((MCG->C1 & MCG_C1_CLKS_MASK) == 0x80U) {
    /* External reference clock is selected */
    if((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x00U) {
      MCGOUTClock = CPU_XTAL_CLK_HZ;   /* System oscillator drives MCG clock */
    } else {
      MCGOUTClock = CPU_XTAL32k_CLK_HZ; /* RTC 32 kHz oscillator drives MCG clock */
    }
  } else { /* (!((MCG->C1 & MCG_C1_CLKS_MASK) == 0x80U)) */
    /* Reserved value */
    return;
  } /* (!((MCG->C1 & MCG_C1_CLKS_MASK) == 0x80U)) */
  SystemCoreClock = (MCGOUTClock / (0x01U + ((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV1_MASK) >> SIM_CLKDIV1_OUTDIV1_SHIFT)));

}