mbed library sources: Modified to operate FRDM-KL25Z at 48MHz from internal 32kHz oscillator (nothing else changed).
Fork of mbed-src by
The only file that changed is: mbed-src-FLL48/targets/cmsis/TARGET_Freescale/TARGET_KL25Z/system_MKL25Z4.h
targets/cmsis/TARGET_Freescale/TARGET_KL05Z/system_MKL05Z4.c
- Committer:
- bogdanm
- Date:
- 2013-09-10
- Revision:
- 20:4263a77256ae
File content as of revision 20:4263a77256ae:
#include <stdint.h> #include "MKL05Z4.h" #define DISABLE_WDOG 1 /* Predefined clock setups 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 = 47.97MHz, BusClock = 23.48MHz */ #define CPU_XTAL_CLK_HZ 32768u /* 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 47972352u /* Default System clock value */ uint32_t SystemCoreClock = DEFAULT_SYSTEM_CLOCK; 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) */ SIM->SCGC5 |= (SIM_SCGC5_PORTB_MASK | SIM_SCGC5_PORTA_MASK); /* Enable clock gate for ports to enable pin routing */ /* SIM_SCGC5: LPTMR=1 */ SIM->SCGC5 |= SIM_SCGC5_LPTMR_MASK; /* SIM_CLKDIV1: OUTDIV1=0,??=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 = (SIM_CLKDIV1_OUTDIV1(0x00) | SIM_CLKDIV1_OUTDIV4(0x01)); /* Update system prescalers */ /* SIM_SOPT1: OSC32KSEL=0 */ SIM->SOPT1 &= (uint32_t)~(uint32_t)(SIM_SOPT1_OSC32KSEL(0x03)); /* System oscillator drives 32 kHz clock for various peripherals */ /* SIM_SOPT2: TPMSRC=2 */ SIM->SOPT2 = (uint32_t)((SIM->SOPT2 & (uint32_t)~(uint32_t)(SIM_SOPT2_TPMSRC(0x01))) | (uint32_t)(SIM_SOPT2_TPMSRC(0x02))); /* Set the TPM clock */ /* PORTA_PCR3: ISF=0,MUX=0 */ PORTA->PCR[3] &= (uint32_t)~(uint32_t)((PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x07))); /* MCG_SC: FCRDIV=1 */ MCG->SC = (uint8_t)((MCG->SC & (uint8_t)~(uint8_t)(MCG_SC_FCRDIV(0x06))) | (uint8_t)(MCG_SC_FCRDIV(0x01))); /* Switch to FEI Mode */ /* MCG_C1: CLKS=0,FRDIV=0,IREFS=1,IRCLKEN=1,IREFSTEN=0 */ MCG->C1 = MCG_C1_CLKS(0x00) | MCG_C1_FRDIV(0x00) | MCG_C1_IREFS_MASK | MCG_C1_IRCLKEN_MASK; /* MCG_C2: LOCRE0=0,??=0,RANGE0=0,HGO0=0,EREFS0=0,LP=0,IRCS=1 */ MCG->C2 = (MCG_C2_RANGE0(0x00) | MCG_C2_IRCS_MASK); /* MCG_C4: DMX32=1,DRST_DRS=1 */ MCG->C4 = (uint8_t)((MCG->C4 & (uint8_t)~(uint8_t)(MCG_C4_DRST_DRS(0x02))) | (uint8_t)(MCG_C4_DMX32_MASK | MCG_C4_DRST_DRS(0x01))); /* OSC0_CR: ERCLKEN=1,??=0,EREFSTEN=0,??=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */ OSC0->CR = OSC_CR_ERCLKEN_MASK; 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 */ } } void SystemCoreClockUpdate(void) { uint32_t MCGOUTClock; uint8_t Divider; if ((MCG->C1 & MCG_C1_CLKS_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 */ } } else { MCGOUTClock = CPU_INT_SLOW_CLK_HZ; /* The slow internal reference clock is selected */ } /* 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 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 { MCGOUTClock = CPU_INT_FAST_CLK_HZ / (1 << ((MCG->SC & MCG_SC_FCRDIV_MASK) >> MCG_SC_FCRDIV_SHIFT)); /* Fast internal reference clock selected */ } } 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 { /* Reserved value */ return; } SystemCoreClock = (MCGOUTClock / (1u + ((SIM->CLKDIV1 & SIM_CLKDIV1_OUTDIV1_MASK) >> SIM_CLKDIV1_OUTDIV1_SHIFT))); }