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system_MKL25Z4.c
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/*
** ###################################################################
** Processor: MKL25Z128VLK4
** Compilers: ARM Compiler
** Freescale C/C++ for Embedded ARM
** GNU C Compiler
** IAR ANSI C/C++ Compiler for ARM
**
** Reference manual: KL25RM, Rev.1, Jun 2012
** Version: rev. 1.1, 2012-06-21
**
** 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: 2012 Freescale Semiconductor, Inc. All Rights Reserved.
**
** http: www.freescale.com
** mail: [email protected]
**
** Revisions:
** - rev. 1.0 (2012-06-13)
** Initial version.
** - rev. 1.1 (2012-06-21)
** Update according to reference manual rev. 1.
**
** ###################################################################
*/
/**
* @file MKL25Z4
* @version 1.1
* @date 2012-06-21
* @brief Device specific configuration file for MKL25Z4 (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 "MKL25Z4.h"
#define DISABLE_WDOG 1
#define CLOCK_SETUP 1
/* Predefined clock setups
0 ... Multipurpose Clock Generator (MCG) in FLL Engaged Internal (FEI) mode
Reference clock source for MCG module is the slow internal clock source 32.768kHz
Core clock = 41.94MHz, BusClock = 13.98MHz
1 ... Multipurpose Clock Generator (MCG) in PLL Engaged External (PEE) mode
Reference clock source for MCG module is an external crystal 8MHz
Core clock = 48MHz, BusClock = 24MHz
2 ... Multipurpose Clock Generator (MCG) in Bypassed Low Power External (BLPE) mode
Core clock/Bus clock derived directly from an external crystal 8MHz with no multiplication
Core clock = 8MHz, BusClock = 8MHz
*/
/*----------------------------------------------------------------------------
Define clock source values
*----------------------------------------------------------------------------*/
#if (CLOCK_SETUP == 0)
#define CPU_XTAL_CLK_HZ 8000000u /* Value of the external crystal or oscillator clock frequency in Hz */
#define CPU_INT_SLOW_CLK_HZ 32768u /* Value of the slow internal oscillator clock frequency in Hz */
#define CPU_INT_FAST_CLK_HZ 4000000u /* Value of the fast internal oscillator clock frequency in Hz */
#define DEFAULT_SYSTEM_CLOCK 41943040u /* Default System clock value */
#elif (CLOCK_SETUP == 1)
#define CPU_XTAL_CLK_HZ 8000000u /* Value of the external crystal or oscillator clock frequency in Hz */
#define CPU_INT_SLOW_CLK_HZ 32768u /* Value of the slow internal oscillator clock frequency in Hz */
#define CPU_INT_FAST_CLK_HZ 4000000u /* Value of the fast internal oscillator clock frequency in Hz */
#define DEFAULT_SYSTEM_CLOCK 48000000u /* Default System clock value */
#elif (CLOCK_SETUP == 2)
#define CPU_XTAL_CLK_HZ 8000000u /* Value of the external crystal or oscillator clock frequency in Hz */
#define CPU_INT_SLOW_CLK_HZ 32768u /* Value of the slow internal oscillator clock frequency in Hz */
#define CPU_INT_FAST_CLK_HZ 4000000u /* Value of the fast internal oscillator clock frequency in Hz */
#define DEFAULT_SYSTEM_CLOCK 8000000u /* Default System clock value */
#endif /* (CLOCK_SETUP == 2) */
/* ----------------------------------------------------------------------------
-- Core clock
---------------------------------------------------------------------------- */
uint32_t SystemCoreClock = DEFAULT_SYSTEM_CLOCK;
/* ----------------------------------------------------------------------------
-- SystemInit()
---------------------------------------------------------------------------- */
void SystemInit (void) {
#if (DISABLE_WDOG)
/* Disable the WDOG module */
/* SIM_COPC: COPT=0,COPCLKS=0,COPW=0 */
SIM->COPC = (uint32_t)0x00u;
#endif /* (DISABLE_WDOG) */
#if (CLOCK_SETUP == 0)
/* SIM->CLKDIV1: OUTDIV1=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,OUTDIV4=2,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
SIM->CLKDIV1 = (uint32_t)0x00020000UL; /* Update system prescalers */
/* Switch to FEI Mode */
/* MCG->C1: CLKS=0,FRDIV=0,IREFS=1,IRCLKEN=1,IREFSTEN=0 */
MCG->C1 = (uint8_t)0x06U;
/* MCG_C2: LOCRE0=0,??=0,RANGE0=0,HGO0=0,EREFS0=0,LP=0,IRCS=0 */
MCG->C2 = (uint8_t)0x00U;
/* MCG->C4: DMX32=0,DRST_DRS=1 */
MCG->C4 = (uint8_t)((MCG->C4 & (uint8_t)~(uint8_t)0xC0U) | (uint8_t)0x20U);
/* OSC0->CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */
OSC0->CR = (uint8_t)0x80U;
/* MCG->C5: ??=0,PLLCLKEN0=0,PLLSTEN0=0,PRDIV0=0 */
MCG->C5 = (uint8_t)0x00U;
/* MCG->C6: LOLIE0=0,PLLS=0,CME0=0,VDIV0=0 */
MCG->C6 = (uint8_t)0x00U;
while((MCG->S & MCG_S_IREFST_MASK) == 0x00U) { /* Check that the source of the FLL reference clock is the internal reference clock. */
}
while((MCG->S & 0x0CU) != 0x00U) { /* Wait until output of the FLL is selected */
}
#elif (CLOCK_SETUP == 1)
/* SIM->SCGC5: PORTA=1 */
SIM->SCGC5 |= (uint32_t)0x0200UL; /* Enable clock gate for ports to enable pin routing */
/* SIM->CLKDIV1: OUTDIV1=1,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,OUTDIV4=1,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
SIM->CLKDIV1 = (uint32_t)0x10010000UL; /* Update system prescalers */
/* PORTA->PCR18: ISF=0,MUX=0 */
PORTA->PCR[18] &= (uint32_t)~0x01000700UL;
/* PORTA->PCR19: ISF=0,MUX=0 */
PORTA->PCR[19] &= (uint32_t)~0x01000700UL;
/* Switch to FBE Mode */
/* OSC0->CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=1,SC4P=0,SC8P=0,SC16P=1 */
OSC0->CR = (uint8_t)0x89U;
/* MCG->C2: LOCRE0=0,??=0,RANGE0=2,HGO0=0,EREFS0=1,LP=0,IRCS=0 */
MCG->C2 = (uint8_t)0x24U;
/* MCG->C1: CLKS=2,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */
MCG->C1 = (uint8_t)0x9AU;
/* MCG->C4: DMX32=0,DRST_DRS=0 */
MCG->C4 &= (uint8_t)~(uint8_t)0xE0U;
/* MCG->C5: ??=0,PLLCLKEN0=0,PLLSTEN0=0,PRDIV0=1 */
MCG->C5 = (uint8_t)0x01U;
/* MCG->C6: LOLIE0=0,PLLS=0,CME0=0,VDIV0=0 */
MCG->C6 = (uint8_t)0x00U;
while((MCG->S & MCG_S_IREFST_MASK) != 0x00U) { /* Check that the source of the FLL reference clock is the external reference clock. */
}
while((MCG->S & 0x0CU) != 0x08U) { /* Wait until external reference clock is selected as MCG output */
}
/* Switch to PBE Mode */
/* MCG->C6: LOLIE0=0,PLLS=1,CME0=0,VDIV0=0 */
MCG->C6 = (uint8_t)0x40U;
while((MCG->S & 0x0CU) != 0x08U) { /* Wait until external reference clock is selected as MCG output */
}
while((MCG->S & MCG_S_LOCK0_MASK) == 0x00U) { /* Wait until locked */
}
/* Switch to PEE Mode */
/* MCG->C1: CLKS=0,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */
MCG->C1 = (uint8_t)0x1AU;
while((MCG->S & 0x0CU) != 0x0CU) { /* Wait until output of the PLL is selected */
}
#elif (CLOCK_SETUP == 2)
/* SIM->SCGC5: PORTA=1 */
SIM->SCGC5 |= (uint32_t)0x0200UL; /* Enable clock gate for ports to enable pin routing */
/* SIM->CLKDIV1: OUTDIV1=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,OUTDIV4=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0,??=0 */
SIM->CLKDIV1 = (uint32_t)0x00000000UL; /* Update system prescalers */
/* PORTA->PCR18: ISF=0,MUX=0 */
PORTA->PCR[18] &= (uint32_t)~0x01000700UL;
/* PORTA->PCR19: ISF=0,MUX=0 */
PORTA->PCR[19] &= (uint32_t)~0x01000700UL;
/* Switch to FBE Mode */
/* OSC0->CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=1,SC4P=0,SC8P=0,SC16P=1 */
OSC0->CR = (uint8_t)0x89U;
/* MCG->C2: LOCRE0=0,??=0,RANGE0=2,HGO0=0,EREFS0=1,LP=0,IRCS=0 */
MCG->C2 = (uint8_t)0x24U;
/* MCG->C1: CLKS=2,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */
MCG->C1 = (uint8_t)0x9AU;
/* MCG->C4: DMX32=0,DRST_DRS=0 */
MCG->C4 &= (uint8_t)~(uint8_t)0xE0U;
/* MCG->C5: ??=0,PLLCLKEN0=0,PLLSTEN0=0,PRDIV0=0 */
MCG->C5 = (uint8_t)0x00U;
/* MCG->C6: LOLIE0=0,PLLS=0,CME0=0,VDIV0=0 */
MCG->C6 = (uint8_t)0x00U;
while((MCG->S & MCG_S_IREFST_MASK) != 0x00U) { /* Check that the source of the FLL reference clock is the external reference clock. */
}
while((MCG->S & 0x0CU) != 0x08U) { /* Wait until external reference clock is selected as MCG output */
}
/* Switch to BLPE Mode */
/* MCG->C2: LOCRE0=0,??=0,RANGE0=2,HGO0=0,EREFS0=1,LP=1,IRCS=0 */
MCG->C2 = (uint8_t)0x26U;
while((MCG->S & 0x0CU) != 0x08U) { /* Wait until external reference clock is selected as MCG output */
}
#endif /* (CLOCK_SETUP == 2) */
}
/* ----------------------------------------------------------------------------
-- SystemCoreClockUpdate()
---------------------------------------------------------------------------- */
void SystemCoreClockUpdate (void) {
uint32_t MCGOUTClock; /* Variable to store output clock frequency of the MCG module */
uint8_t Divider;
if ((MCG->C1 & MCG_C1_CLKS_MASK) == 0x0u) {
/* Output of FLL or PLL is selected */
if ((MCG->C6 & MCG_C6_PLLS_MASK) == 0x0u) {
/* FLL is selected */
if ((MCG->C1 & MCG_C1_IREFS_MASK) == 0x0u) {
/* External reference clock is selected */
MCGOUTClock = CPU_XTAL_CLK_HZ; /* System oscillator drives MCG clock */
Divider = (uint8_t)(1u << ((MCG->C1 & MCG_C1_FRDIV_MASK) >> MCG_C1_FRDIV_SHIFT));
MCGOUTClock = (MCGOUTClock / Divider); /* Calculate the divided FLL reference clock */
if ((MCG->C2 & MCG_C2_RANGE0_MASK) != 0x0u) {
MCGOUTClock /= 32u; /* If high range is enabled, additional 32 divider is active */
} /* ((MCG->C2 & MCG_C2_RANGE0_MASK) != 0x0u) */
} else { /* (!((MCG->C1 & MCG_C1_IREFS_MASK) == 0x0u)) */
MCGOUTClock = CPU_INT_SLOW_CLK_HZ; /* The slow internal reference clock is selected */
} /* (!((MCG->C1 & MCG_C1_IREFS_MASK) == 0x0u)) */
/* Select correct multiplier to calculate the MCG output clock */
switch (MCG->C4 & (MCG_C4_DMX32_MASK | MCG_C4_DRST_DRS_MASK)) {
case 0x0u:
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 { /* (!((MCG->C6 & MCG_C6_PLLS_MASK) == 0x0u)) */
/* PLL is selected */
Divider = (1u + (MCG->C5 & MCG_C5_PRDIV0_MASK));
MCGOUTClock = (uint32_t)(CPU_XTAL_CLK_HZ / Divider); /* Calculate the PLL reference clock */
Divider = ((MCG->C6 & MCG_C6_VDIV0_MASK) + 24u);
MCGOUTClock *= Divider; /* Calculate the MCG output clock */
} /* (!((MCG->C6 & MCG_C6_PLLS_MASK) == 0x0u)) */
} else if ((MCG->C1 & MCG_C1_CLKS_MASK) == 0x40u) {
/* Internal reference clock is selected */
if ((MCG->C2 & MCG_C2_IRCS_MASK) == 0x0u) {
MCGOUTClock = CPU_INT_SLOW_CLK_HZ; /* Slow internal reference clock selected */
} else { /* (!((MCG->C2 & MCG_C2_IRCS_MASK) == 0x0u)) */
MCGOUTClock = CPU_INT_FAST_CLK_HZ / (1 << ((MCG->SC & MCG_SC_FCRDIV_MASK) >> MCG_SC_FCRDIV_SHIFT)); /* Fast internal reference clock selected */
} /* (!((MCG->C2 & MCG_C2_IRCS_MASK) == 0x0u)) */
} else if ((MCG->C1 & MCG_C1_CLKS_MASK) == 0x80u) {
/* External reference clock is selected */
MCGOUTClock = CPU_XTAL_CLK_HZ; /* System oscillator drives MCG clock */
} else { /* (!((MCG->C1 & MCG_C1_CLKS_MASK) == 0x80u)) */
/* Reserved value */
return;
} /* (!((MCG->C1 & MCG_C1_CLKS_MASK) == 0x80u)) */
SystemCoreClock = (MCGOUTClock / (1u + ((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV1_MASK) >> SIM_CLKDIV1_OUTDIV1_SHIFT)));
}