system_msp432p401r.c

/******************************************************************************
* @file     system_msp432p401r.c
* @brief    CMSIS Cortex-M4F Device Peripheral Access Layer Source File for
*           MSP432P401R
* @version  2.200
* @date     2016-05-09
*
* @note     View configuration instructions embedded in comments
*
******************************************************************************/
//*****************************************************************************
//
// Copyright (C) 2015 - 2016 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
//  Redistributions of source code must retain the above copyright
//  notice, this list of conditions and the following disclaimer.
//
//  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.
//
//  Neither the name of Texas Instruments Incorporated 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
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//*****************************************************************************

#include <stdint.h>
#include "msp.h"

/*--------------------- Configuration Instructions ----------------------------
   1. If you prefer to halt the Watchdog Timer, set __HALT_WDT to 1:
   #define __HALT_WDT       1
   2. Insert your desired CPU frequency in Hz at:
   #define __SYSTEM_CLOCK   12000000
   3. If you prefer the DC-DC power regulator (more efficient at higher
       frequencies), set the __REGULATOR to 1:
   #define __REGULATOR      1
 *---------------------------------------------------------------------------*/

/*--------------------- Watchdog Timer Configuration ------------------------*/
//  Halt the Watchdog Timer
//     <0> Do not halt the WDT
//     <1> Halt the WDT
#define __HALT_WDT         1

/*--------------------- CPU Frequency Configuration -------------------------*/
//  CPU Frequency
//     <1500000> 1.5 MHz
//     <3000000> 3 MHz
//     <12000000> 12 MHz
//     <24000000> 24 MHz
//     <48000000> 48 MHz
#define  __SYSTEM_CLOCK    3000000

/*--------------------- Power Regulator Configuration -----------------------*/
//  Power Regulator Mode
//     <0> LDO
//     <1> DC-DC
#define __REGULATOR        0

/*----------------------------------------------------------------------------
   Define clocks, used for SystemCoreClockUpdate()
 *---------------------------------------------------------------------------*/
#define __VLOCLK           10000
#define __MODCLK           24000000
#define __LFXT             32768
#define __HFXT             48000000

/*----------------------------------------------------------------------------
   Clock Variable definitions
 *---------------------------------------------------------------------------*/
uint32_t SystemCoreClock = __SYSTEM_CLOCK;  /*!< System Clock Frequency (Core Clock)*/

/**
 * Update SystemCoreClock variable
 *
 * @param  none
 * @return none
 *
 * @brief  Updates the SystemCoreClock with current core Clock
 *         retrieved from cpu registers.
 */
void SystemCoreClockUpdate(void)
{
    uint32_t source, divider;
    uint8_t dividerValue;

    float dcoConst;
    int32_t calVal;
    uint32_t centeredFreq;
    int16_t dcoTune;

    divider = (CS->CTL1 & CS_CTL1_DIVM_MASK) >> CS_CTL1_DIVM_OFS;
    dividerValue = 1 << divider;
    source = CS->CTL1 & CS_CTL1_SELM_MASK;

    switch(source)
    {
    case CS_CTL1_SELM__LFXTCLK:
        if(BITBAND_PERI(CS->IFG, CS_IFG_LFXTIFG_OFS))
        {
            // Clear interrupt flag
            CS->KEY = CS_KEY_VAL;
            CS->CLRIFG |= CS_CLRIFG_CLR_LFXTIFG;
            CS->KEY = 1;

            if(BITBAND_PERI(CS->IFG, CS_IFG_LFXTIFG_OFS))
            {
                if(BITBAND_PERI(CS->CLKEN, CS_CLKEN_REFOFSEL_OFS))
                {
                    SystemCoreClock = (128000 / dividerValue);
                }
                else
                {
                    SystemCoreClock = (32000 / dividerValue);
                }
            }
            else
            {
                SystemCoreClock = __LFXT / dividerValue;
            }
        }
        else
        {
            SystemCoreClock = __LFXT / dividerValue;
        }
        break;
    case CS_CTL1_SELM__VLOCLK:
        SystemCoreClock = __VLOCLK / dividerValue;
        break;
    case CS_CTL1_SELM__REFOCLK:
        if (BITBAND_PERI(CS->CLKEN, CS_CLKEN_REFOFSEL_OFS))
        {
            SystemCoreClock = (128000 / dividerValue);
        }
        else
        {
            SystemCoreClock = (32000 / dividerValue);
        }
        break;
    case CS_CTL1_SELM__DCOCLK:
        dcoTune = (CS->CTL0 & CS_CTL0_DCOTUNE_MASK) >> CS_CTL0_DCOTUNE_OFS;
    
        switch(CS->CTL0 & CS_CTL0_DCORSEL_MASK)
        {
        case CS_CTL0_DCORSEL_0:
            centeredFreq = 1500000;
            break;
        case CS_CTL0_DCORSEL_1:
            centeredFreq = 3000000;
            break;
        case CS_CTL0_DCORSEL_2:
            centeredFreq = 6000000;
            break;
        case CS_CTL0_DCORSEL_3:
            centeredFreq = 12000000;
            break;
        case CS_CTL0_DCORSEL_4:
            centeredFreq = 24000000;
            break;
        case CS_CTL0_DCORSEL_5:
            centeredFreq = 48000000;
            break;
        }

        if(dcoTune == 0)
        {
            SystemCoreClock = centeredFreq;
        }
        else
        {

            if(dcoTune & 0x1000)
            {
                dcoTune = dcoTune | 0xF000;
            }

            if (BITBAND_PERI(CS->CTL0, CS_CTL0_DCORES_OFS))
            {
                dcoConst = *((float *) &TLV->DCOER_CONSTK_RSEL04);
                calVal = TLV->DCOER_FCAL_RSEL04;
            }
            /* Internal Resistor */
            else
            {
                dcoConst = *((float *) &TLV->DCOIR_CONSTK_RSEL04);
                calVal = TLV->DCOIR_FCAL_RSEL04;
            }

            SystemCoreClock = (uint32_t) ((centeredFreq)
                               / (1
                                    - ((dcoConst * dcoTune)
                                            / (8 * (1 + dcoConst * (768 - calVal))))));
        }
        break;
    case CS_CTL1_SELM__MODOSC:
        SystemCoreClock = __MODCLK / dividerValue;
        break;
    case CS_CTL1_SELM__HFXTCLK:
        if(BITBAND_PERI(CS->IFG, CS_IFG_HFXTIFG_OFS))
        {
            // Clear interrupt flag
            CS->KEY = CS_KEY_VAL;
            CS->CLRIFG |= CS_CLRIFG_CLR_HFXTIFG;
            CS->KEY = 1;

            if(BITBAND_PERI(CS->IFG, CS_IFG_HFXTIFG_OFS))
            {
                if(BITBAND_PERI(CS->CLKEN, CS_CLKEN_REFOFSEL_OFS))
                {
                    SystemCoreClock = (128000 / dividerValue);
                }
                else
                {
                    SystemCoreClock = (32000 / dividerValue);
                }
            }
            else
            {
                SystemCoreClock = __HFXT / dividerValue;
            }
        }
        else
        {
            SystemCoreClock = __HFXT / dividerValue;
        }
        break;
    }
}

/**
 * Initialize the system
 *
 * @param  none
 * @return none
 *
 * @brief  Setup the microcontroller system.
 *
 * Performs the following initialization steps:
 *     1. Enables the FPU
 *     2. Halts the WDT if requested
 *     3. Enables all SRAM banks
 *     4. Sets up power regulator and VCORE
 *     5. Enable Flash wait states if needed
 *     6. Change MCLK to desired frequency
 *     7. Enable Flash read buffering
 */
void SystemInit(void)
{
    // Enable FPU if used
    #if (__FPU_USED == 1)                              /* __FPU_USED is defined in core_cm4.h */
    SCB->CPACR |= ((3UL << 10 * 2) |                   /* Set CP10 Full Access */
                   (3UL << 11 * 2));                   /* Set CP11 Full Access */
    #endif

    #if (__HALT_WDT == 1)
    WDT_A->CTL = WDT_A_CTL_PW | WDT_A_CTL_HOLD;         // Halt the WDT
    #endif

    SYSCTL->SRAM_BANKEN = SYSCTL_SRAM_BANKEN_BNK7_EN;   // Enable all SRAM banks

    #if (__SYSTEM_CLOCK == 1500000)                                  // 1.5 MHz
    // Default VCORE is LDO VCORE0 so no change necessary

    // Switches LDO VCORE0 to DCDC VCORE0 if requested
    #if __REGULATOR
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    PCM->CTL0 = PCM_CTL0_KEY_VAL | PCM_CTL0_AMR_4;
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    #endif

    // No flash wait states necessary

    // DCO = 1.5 MHz; MCLK = source
    CS->KEY = CS_KEY_VAL;                                 // Unlock CS module for register access
    CS->CTL0 = CS_CTL0_DCORSEL_0;                                // Set DCO to 1.5MHz
    CS->CTL1 &= ~(CS_CTL1_SELM_MASK | CS_CTL1_DIVM_MASK) | CS_CTL1_SELM__DCOCLK;  // Select MCLK as DCO source
    CS->KEY = 0;

    // Set Flash Bank read buffering
    FLCTL->BANK0_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);
    FLCTL->BANK1_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);

    #elif (__SYSTEM_CLOCK == 3000000)                                  // 3 MHz
    // Default VCORE is LDO VCORE0 so no change necessary

    // Switches LDO VCORE0 to DCDC VCORE0 if requested
    #if __REGULATOR
    while(PCM->CTL1 & PCM_CTL1_PMR_BUSY);
    PCM->CTL0 = PCM_CTL0_KEY_VAL | PCM_CTL0_AMR_4;
    while(PCM->CTL1 & PCM_CTL1_PMR_BUSY);
    #endif

    // No flash wait states necessary

    // DCO = 3 MHz; MCLK = source
    CS->KEY = CS_KEY_VAL;                                                         // Unlock CS module for register access
    CS->CTL0 = CS_CTL0_DCORSEL_1;                                                  // Set DCO to 1.5MHz
    CS->CTL1 &= ~(CS_CTL1_SELM_MASK | CS_CTL1_DIVM_MASK) | CS_CTL1_SELM__DCOCLK;  // Select MCLK as DCO source
    CS->KEY = 0;

    // Set Flash Bank read buffering
    FLCTL->BANK0_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);
    FLCTL->BANK1_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);

    #elif (__SYSTEM_CLOCK == 12000000)                                // 12 MHz
    // Default VCORE is LDO VCORE0 so no change necessary

    // Switches LDO VCORE0 to DCDC VCORE0 if requested
    #if __REGULATOR
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    PCM->CTL0 = PCM_CTL0_KEY_VAL | PCM_CTL0_AMR_4;
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    #endif

    // No flash wait states necessary

    // DCO = 12 MHz; MCLK = source
    CS->KEY = CS_KEY_VAL;                                                         // Unlock CS module for register access
    CS->CTL0 = CS_CTL0_DCORSEL_3;                                                  // Set DCO to 12MHz
    CS->CTL1 &= ~(CS_CTL1_SELM_MASK | CS_CTL1_DIVM_MASK) | CS_CTL1_SELM__DCOCLK;  // Select MCLK as DCO source
    CS->KEY = 0;

    // Set Flash Bank read buffering
    FLCTL->BANK0_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);
    FLCTL->BANK1_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);

    #elif (__SYSTEM_CLOCK == 24000000)                                // 24 MHz
    // Default VCORE is LDO VCORE0 so no change necessary

    // Switches LDO VCORE0 to DCDC VCORE0 if requested
    #if __REGULATOR
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    PCM->CTL0 = PCM_CTL0_KEY_VAL | PCM_CTL0_AMR_4;
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    #endif

    // 1 flash wait state (BANK0 VCORE0 max is 12 MHz)
    FLCTL->BANK0_RDCTL &= ~FLCTL_BANK0_RDCTL_WAIT_MASK | FLCTL_BANK0_RDCTL_WAIT_1;
    FLCTL->BANK1_RDCTL &= ~FLCTL_BANK0_RDCTL_WAIT_MASK | FLCTL_BANK0_RDCTL_WAIT_1;

    // DCO = 24 MHz; MCLK = source
    CS->KEY = CS_KEY_VAL;                                                         // Unlock CS module for register access
    CS->CTL0 = CS_CTL0_DCORSEL_4;                                                  // Set DCO to 24MHz
    CS->CTL1 &= ~(CS_CTL1_SELM_MASK | CS_CTL1_DIVM_MASK) | CS_CTL1_SELM__DCOCLK;  // Select MCLK as DCO source
    CS->KEY = 0;

    // Set Flash Bank read buffering
    FLCTL->BANK0_RDCTL |= (FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);
    FLCTL->BANK1_RDCTL &= ~(FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);

    #elif (__SYSTEM_CLOCK == 48000000)                                // 48 MHz
    // Switches LDO VCORE0 to LDO VCORE1; mandatory for 48 MHz setting
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    PCM->CTL0 = PCM_CTL0_KEY_VAL | PCM_CTL0_AMR_1;
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));

    // Switches LDO VCORE1 to DCDC VCORE1 if requested
    #if __REGULATOR
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    PCM->CTL0 = PCM_CTL0_KEY_VAL | PCM_CTL0_AMR_5;
    while((PCM->CTL1 & PCM_CTL1_PMR_BUSY));
    #endif

    // 2 flash wait states (BANK0 VCORE1 max is 16 MHz, BANK1 VCORE1 max is 32 MHz)
    FLCTL->BANK0_RDCTL &= ~FLCTL_BANK0_RDCTL_WAIT_MASK | FLCTL_BANK0_RDCTL_WAIT_2;
    FLCTL->BANK1_RDCTL &= ~FLCTL_BANK1_RDCTL_WAIT_MASK | FLCTL_BANK1_RDCTL_WAIT_2;

    // DCO = 48 MHz; MCLK = source
    CS->KEY = CS_KEY_VAL;                                                         // Unlock CS module for register access
    CS->CTL0 = CS_CTL0_DCORSEL_5;                                                  // Set DCO to 48MHz
    CS->CTL1 &= ~(CS_CTL1_SELM_MASK | CS_CTL1_DIVM_MASK) | CS_CTL1_SELM__DCOCLK;  // Select MCLK as DCO source
    CS->KEY = 0;

    // Set Flash Bank read buffering
    FLCTL->BANK0_RDCTL |= (FLCTL_BANK0_RDCTL_BUFD | FLCTL_BANK0_RDCTL_BUFI);
    FLCTL->BANK1_RDCTL |= (FLCTL_BANK1_RDCTL_BUFD | FLCTL_BANK1_RDCTL_BUFI);
    #endif

}