/* ** ################################################################### ** Compilers: ARM Compiler ** Freescale C/C++ for Embedded ARM ** GNU C Compiler ** IAR ANSI C/C++ Compiler for ARM ** ** ** ** Version: rev. 1.0, 2011-12-15 ** ** 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: 2015 Freescale Semiconductor, Inc. All Rights Reserved. ** ** http: www.freescale.com ** mail: support@freescale.com ** ** Revisions: ** - rev. 1.0 (2011-12-15) ** Initial version ** ** ################################################################### */ /** * @file MK20DX256 * @version 1.0 * @date 2011-12-15 * @brief Device specific configuration file for MK20DX256 (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 #include "MK20DX256.h" #define DISABLE_WDOG 1 #define CLOCK_SETUP 3 /* 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 = 41.94MHz This works on Teensy3.1 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 = 48MHz 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 3 ... Multipurpose Clock Generator (MCG) in PLL Engaged External (PEE) mode Reference clock source for MCG module is an external crystal 16MHz Core clock = 72MHz, BusClock = 48MHz This is the default Teensy3.1 72Mhz set up */ /*---------------------------------------------------------------------------- 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_XTAL32k_CLK_HZ 32768u /* Value of the external 32k 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_XTAL32k_CLK_HZ 32768u /* Value of the external 32k 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_XTAL32k_CLK_HZ 32768u /* Value of the external 32k 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 */ #elif (CLOCK_SETUP == 3) #define CPU_XTAL_CLK_HZ 16000000u /* Value of the external crystal or oscillator clock frequency in Hz */ #define CPU_XTAL32k_CLK_HZ 32768u /* Value of the external 32k 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 72000000u /* Default System clock value */ #endif /* (CLOCK_SETUP == 2) */ /* ---------------------------------------------------------------------------- -- Core clock ---------------------------------------------------------------------------- */ uint32_t SystemCoreClock = DEFAULT_SYSTEM_CLOCK; /* ---------------------------------------------------------------------------- -- SystemInit() ---------------------------------------------------------------------------- */ void SystemInit (void) { /* SystemInit MUST NOT use any variables from the .data section, as this section is not loaded yet! */ #if (DISABLE_WDOG) /* Disable the WDOG module */ /* WDOG_UNLOCK: WDOGUNLOCK=0xC520 */ WDOG->UNLOCK = (uint16_t)0xC520u; /* Key 1 */ /* WDOG_UNLOCK : WDOGUNLOCK=0xD928 */ WDOG->UNLOCK = (uint16_t)0xD928u; /* Key 2 */ /* WDOG_STCTRLH: DISTESTWDOG=0,BYTESEL=0,TESTSEL=0,TESTWDOG=0,STNDBYEN=1,WAITEN=1,STOPEN=1,DBGEN=0,ALLOWUPDATE=1,WINEN=0,IRQRSTEN=0,CLKSRC=1,WDOGEN=0 */ WDOG->STCTRLH = (uint16_t)0x01D2u; #endif /* (DISABLE_WDOG) */ #if (CLOCK_SETUP == 0) /* SIM->CLKDIV1: OUTDIV1=0,OUTDIV2=0,OUTDIV4=1 Set Prescalers 41.94MHz cpu, 41.94MHz system, 20.97MHz flash*/ SIM->CLKDIV1 = SIM_CLKDIV1_OUTDIV4(1); /* Switch to FEI Mode */ /* MCG->C1: CLKS=0,FRDIV=0,IREFS=1,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_IREFS_MASK | MCG_C1_IRCLKEN_MASK; /* MCG->C2: LOCKRE0=0,RANGE0=0,HGO=0,EREFS=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); /* MCG->C5: PLLCLKEN=0,PLLSTEN=0,PRDIV0=0 */ MCG->C5 = (uint8_t)0x00u; /* MCG->C6: LOLIE=0,PLLS=0,CME=0,VDIV0=0 */ MCG->C6 = (uint8_t)0x00u; while((MCG->S & MCG_S_IREFST_MASK) == 0u) { } /* 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->CLKDIV1: OUTDIV1=0,OUTDIV2=0,OUTDIV4=1 Set Prescalers 48MHz cpu, 48MHz system, 24MHz flash*/ SIM->CLKDIV1 = SIM_CLKDIV1_OUTDIV4(1); /* Switch to FBE Mode */ /* OSC0->CR: ERCLKEN=0,EREFSTEN=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */ OSC0->CR = (uint8_t)0x00u; /* MCG->C7: OSCSEL=0 */ MCG->C7 = (uint8_t)0x00u; /* MCG->C2: LOCKRE0=0,RANGE0=2,HGO=0,EREFS=1,LP=0,IRCS=0 */ MCG->C2 = MCG_C2_RANGE0(2); /* MCG->C1: CLKS=2,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_CLKS(2) | MCG_C1_FRDIV(3) | MCG_C1_IRCLKEN_MASK; /* MCG->C4: DMX32=0,DRST_DRS=0 */ MCG->C4 &= (uint8_t)~(uint8_t)0xE0u; /* MCG->C5: PLLCLKEN=0,PLLSTEN=0,PRDIV0=3 */ MCG->C5 = MCG_C5_PRDIV0(3); /* MCG->C6: LOLIE=0,PLLS=0,CME=0,VDIV0=0 */ MCG->C6 = (uint8_t)0x00u; while((MCG->S & MCG_S_OSCINIT0_MASK) == 0u) { } /* Check that the oscillator is running */ while((MCG->S & 0x0Cu) != 0x08u) { } /* Wait until external reference clock is selected as MCG output */ /* Switch to PBE Mode */ /* MCG_C5: PLLCLKEN=0,PLLSTEN=0,PRDIV0=3 */ MCG->C5 = MCG_C5_PRDIV0(3); /* MCG->C6: LOLIE=0,PLLS=1,CME=0,VDIV0=0 */ MCG->C6 = MCG_C6_PLLS_MASK; while((MCG->S & MCG_S_PLLST_MASK) == 0u) { } /* Wait until the source of the PLLS clock has switched to the PLL */ while((MCG->S & MCG_S_LOCK0_MASK) == 0u) { } /* Wait until locked */ /* Switch to PEE Mode */ /* MCG->C1: CLKS=0,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_FRDIV(3) | MCG_C1_IRCLKEN_MASK; while((MCG->S & 0x0Cu) != 0x0Cu) { } /* Wait until output of the PLL is selected */ while((MCG->S & MCG_S_LOCK0_MASK) == 0u) { } /* Wait until locked */ #elif (CLOCK_SETUP == 2) /* SIM->CLKDIV1: OUTDIV1=0,OUTDIV2=0,OUTDIV4=1 Set Prescalers 8MHz cpu, 8MHz system, 8MHz flash*/ SIM->CLKDIV1 = SIM_CLKDIV1_OUTDIV4(1); /* Switch to FBE Mode */ /* OSC0->CR: ERCLKEN=0,EREFSTEN=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */ OSC0->CR = (uint8_t)0x00u; /* MCG->C7: OSCSEL=0 */ MCG->C7 = (uint8_t)0x00u; /* MCG->C2: LOCKRE0=0,RANGE0=2,HGO=0,EREFS=1,LP=0,IRCS=0 */ MCG->C2 = MCG_C2_RANGE0(2) | MCG_C2_EREFS0_MASK; /* MCG->C1: CLKS=2,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_CLKS(2) | MCG_C1_FRDIV(3) | MCG_C1_IRCLKEN_MASK; /* MCG->C4: DMX32=0,DRST_DRS=0 */ MCG->C4 &= (uint8_t)~(uint8_t)0xE0u; /* MCG->C5: PLLCLKEN=0,PLLSTEN=0,PRDIV0=0 */ MCG->C5 = (uint8_t)0x00u; /* MCG->C6: LOLIE=0,PLLS=0,CME=0,VDIV0=0 */ MCG->C6 = (uint8_t)0x00u; while((MCG->S & MCG_S_OSCINIT0_MASK) == 0u) { } /* Check that the oscillator is running */ while((MCG->S & 0x0CU) != 0x08u) { } /* Wait until external reference clock is selected as MCG output */ /* Switch to BLPE Mode */ /* MCG->C2: LOCKRE0=0,RANGE0=2,HGO=0,EREFS=1,LP=0,IRCS=0 */ MCG->C2 = MCG_C2_RANGE0(2) | MCG_C2_EREFS0_MASK; #elif (CLOCK_SETUP == 3) /* SIM->CLKDIV1: OUTDIV1=0,OUTDIV2=0,OUTDIV4=1 Set Prescalers 72MHz cpu, 72MHz system, 36MHz flash*/ SIM->CLKDIV1 = SIM_CLKDIV1_OUTDIV4(1); /* SIM->CLKDIV2: USBDIV=2,USBFRAC=1 Divide 72MHz system clock for USB 48MHz */ SIM->CLKDIV2 = SIM_CLKDIV2_USBDIV(2) | SIM_CLKDIV2_USBFRAC_MASK; /* OSC0->CR: ERCLKEN=0,EREFSTEN=0,SC2P=1,SC4P=0,SC8P=1,SC16P=0 10pF loading capacitors for 16MHz system oscillator*/ OSC0->CR = OSC_CR_SC8P_MASK | OSC_CR_SC2P_MASK; /* Switch to FBE Mode */ /* MCG->C7: OSCSEL=0 */ MCG->C7 = (uint8_t)0x00u; /* MCG->C2: LOCKRE0=0,RANGE0=2,HGO=0,EREFS=1,LP=0,IRCS=0 */ MCG->C2 = MCG_C2_RANGE0(2) | MCG_C2_EREFS0_MASK; //MCG->C2 = (uint8_t)0x24u; /* MCG->C1: CLKS=2,FRDIV=3,IREFS=0,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_CLKS(2) | MCG_C1_FRDIV(3) | MCG_C1_IRCLKEN_MASK; /* MCG->C4: DMX32=0,DRST_DRS=0,FCTRIM=0,SCFTRIM=0 */ MCG->C4 &= (uint8_t)~(uint8_t)0xE0u; /* MCG->C5: PLLCLKEN=0,PLLSTEN=0,PRDIV0=7 */ MCG->C5 = MCG_C5_PRDIV0(7); /* MCG->C6: LOLIE=0,PLLS=0,CME=0,VDIV0=0 */ MCG->C6 = (uint8_t)0x00u; while((MCG->S & MCG_S_OSCINIT0_MASK) == 0u) { } /* Check that the oscillator is running */ while((MCG->S & 0x0Cu) != 0x08u) { } /* Wait until external reference clock is selected as MCG output */ /* Switch to PBE Mode */ /* MCG_C5: PLLCLKEN=0,PLLSTEN=0,PRDIV0=5 */ MCG->C5 = MCG_C5_PRDIV0(5); /* MCG->C6: LOLIE=0,PLLS=1,CME=0,VDIV0=3 */ MCG->C6 = MCG_C6_PLLS_MASK | MCG_C6_VDIV0(3); while((MCG->S & MCG_S_PLLST_MASK) == 0u) { } /* Wait until the source of the PLLS clock has switched to the PLL */ while((MCG->S & MCG_S_LOCK0_MASK) == 0u) { } /* Wait until locked */ /* Switch to PEE Mode */ /* MCG->C1: CLKS=0,FRDIV=2,IREFS=0,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_FRDIV(2) | MCG_C1_IRCLKEN_MASK; while((MCG->S & 0x0Cu) != 0x0Cu) { } /* Wait until output of the PLL is selected */ while((MCG->S & MCG_S_LOCK0_MASK) == 0u) { } /* Wait until locked */ #endif /* (CLOCK_SETUP) */ } /* ---------------------------------------------------------------------------- -- 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 */ if ((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x0u) { MCGOUTClock = CPU_XTAL_CLK_HZ; /* System oscillator drives MCG clock */ } else { /* (!((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x0u)) */ MCGOUTClock = CPU_XTAL32k_CLK_HZ; /* RTC 32 kHz oscillator drives MCG clock */ } /* (!((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x0u)) */ 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 */ if ((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x0u) { MCGOUTClock = CPU_XTAL_CLK_HZ; /* System oscillator drives MCG clock */ } else { /* (!((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x0u)) */ MCGOUTClock = CPU_XTAL32k_CLK_HZ; /* RTC 32 kHz oscillator drives MCG clock */ } /* (!((MCG->C7 & MCG_C7_OSCSEL_MASK) == 0x0u)) */ } 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))); }