KL27Z644 HIRC mode

[radunasui]

I have been trying to enable the HIRC MCG mode on a MKL27Z microcontroller. As far as I know, there are at least two ways to do this: to write the code using the device registers or to use KDSK device specific drivers.

For the first approach my could would look like this:

#include "fsl_device_registers.h"

void main(void)

{

  MCG_MC |= MCG_MC_HIRCEN_MASK; //enable the HIRC

  MCG_MC |= MCG_MC_HIRCLPEN_MASK;

  MCG_C1 |= MCG_C1_CLKS(0b00); //use the HIRC oscillator as the system clock

  for (int i = 0 ; i < 2000 ; i++)

  {if (((MCG_S & MCG_S_CLKST_MASK) >> MCG_S_CLKST_SHIFT) == 0b00) break; // jump out early if CLKST shows HIRC CLK selected before loop finishes

  }

}

The problem with this example is that it does not enter the HIRC mode. I have tried the same approach on on enabling other modes and it works. Am I missing something?

The second approach is to use one of the functions provided in the low level HAL driver, fsl_mcglite_hal.h:

static void CLOCK_HAL_SetHircCmd (MCG_Type  *base, bool enable)

Although the latter will mean less lines of code, I cannot find any reference to what possible values I could give to base ( I could not find any reference to MCG_Type type).

Any thoughts??

Cheers

[kerryzhou]

Hi Radu Nasui,

     You can refer to the KSDK1.3.0, KL27Z644 sample code.

     After you install the KSDK1.3.0, please refer to the SystemInit function in system_MKL27Z644.c, and define CLOCK_SETUP=1 in system_MKL27Z644.h.

  You can find the system_MKL27Z644.h and system_MKL27Z644.c in default folder: C:\Freescale\KSDK_1.3.0\platform\devices\MKL27Z644\startup

   When you configure CLOCK_SETUP=1, the systeminit is using MCG_MODE_HIRC.

#elif (CLOCK_SETUP == 1)

  #define DEFAULT_SYSTEM_CLOCK         48000000u           /* Default System clock value */

  #define CPU_INT_SLOW_CLK_HZ          8000000u            /* Value of the slow internal oscillator clock frequency in Hz  */

  #define MCG_MODE                     MCG_MODE_HIRC       /* Clock generator mode */

  /* MCG_C1: CLKS=0,IRCLKEN=0,IREFSTEN=0 */

  #define MCG_C1_VALUE                 0x00u               /* MCG_C1 */

  /* MCG_C2: RANGE0=0,HGO0=0,EREFS0=0,IRCS=1 */

  #define MCG_C2_VALUE                 0x01u               /* MCG_C2 */

  /* MCG_SC: FCRDIV=0 */

  #define MCG_SC_VALUE                 0x00u               /* MCG_SC */

  /* MCG_MC: HIRCEN=1 LIRC_DIV2=0 */

  #define MCG_MC_VALUE                 0x80u               /* MCG_MC */

  /* OSC0_CR: ERCLKEN=0,EREFSTEN=0,SC2P=0,SC4P=0,SC8P=0,SC16P=0 */

  #define OSC0_CR_VALUE                0x00u               /* OSC0_CR */

  /* SMC_PMCTRL: RUNM=0,STOPA=0,STOPM=0 */

  #define SMC_PMCTRL_VALUE             0x00u               /* SMC_PMCTRL */

  /* SIM_CLKDIV1: OUTDIV1=0,OUTDIV4=1 */

  #define SYSTEM_SIM_CLKDIV1_VALUE     0x10000u            /* SIM_CLKDIV1 */

  /* SIM_SOPT1: OSC32KSEL=0,OSC32KOUT=0 */

  #define SYSTEM_SIM_SOPT1_VALUE       0x00000000u         /* SIM_SOPT1 */

  /* SIM_SOPT2: LPUART1SRC=0,LPUART0SRC=0,TPMSRC=3,FLEXIOSRC=0,USBSRC=0,CLKOUTSEL=0,RTCCLKOUTSEL=0 */

  #define SYSTEM_SIM_SOPT2_VALUE       0x03000000U         /* SIM_SOPT2 */

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Jingjing

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[radunasui]

Thanks, works this way too!

Do you know though how to find the set of values MCG_Type can take?

Cheers

[kerryzhou]

Hi Radu Nasui,

MCG_Type is defined like this:

typedef struct {

  __IO uint8_t C1;                                 /**< MCG Control Register 1, offset: 0x0 */

  __IO uint8_t C2;                                 /**< MCG Control Register 2, offset: 0x1 */

       uint8_t RESERVED_0[4];

  __I  uint8_t S;                                  /**< MCG Status Register, offset: 0x6 */

       uint8_t RESERVED_1[1];

  __IO uint8_t SC;                                 /**< MCG Status and Control Register, offset: 0x8 */

       uint8_t RESERVED_2[15];

  __IO uint8_t MC;                                 /**< MCG Miscellaneous Control Register, offset: 0x18 */

} MCG_Type, *MCG_MemMapPtr;

Actually, the value of MCG_Type is just the data defined in the header file system_MKL27Z644.h:

  #define MCG_C1_VALUE                 0x00u               /* MCG_C1 */

  /* MCG_C2: RANGE0=0,HGO0=0,EREFS0=0,IRCS=1 */

  #define MCG_C2_VALUE                 0x01u               /* MCG_C2 */

  /* MCG_SC: FCRDIV=0 */

  #define MCG_SC_VALUE                 0x00u               /* MCG_SC */

  /* MCG_MC: HIRCEN=1 LIRC_DIV2=0 */

  #define MCG_MC_VALUE                 0x80u               /* MCG_MC */

Because in the system_MKL27Z644.c, you will get the following code :

MCG->SC = MCG_SC_VALUE;	/* Set SC (internal reference clock divider) */
MCG->MC = MCG_MC_VALUE;	/* Set MC (high-frequency IRC enable, second LIRC divider) */
MCG->C1 = MCG_C1_VALUE;	/* Set C1 (clock source selection, int. reference enable etc.) */
MCG->C2 = MCG_C2_VALUE;	/* Set C2 (ext. and int. reference clock selection) */
OSC0->CR = OSC0_CR_VALUE;	/* Set OSC0_CR (OSCERCLK enable, oscillator capacitor load) */

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Jingjing

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[radunasui]

Thanks for the answer!

I still don't know though how should I call the following function:

               uint32_t CLOCK_HAL_GetOutClk ( MCG_Type   *base )

I was trying to do the following:

          clock = CLOCK_HAL_GetOutClk(MCG_MemMapPtr);

But I am getting an error:      expected expression before 'MCG_MemMapPtr'

How should I go about solving this one?

Thanks

[radunasui]

Found it.

For reference, all these information can be found in the device header file, in my case MKL27Z644.h

clock = CLOCK_HAL_GetOutClk(MCG);

Cheers

[kerryzhou]

Yes, actually, you can refer to the fsl_clock_MKL27Z644.c file which you can find from :C:\Freescale\KSDK_1.3.0\platform\system\src\clock\MKL27Z644

clock_manager_error_code_t CLOCK_SYS_GetFreq(clock_names_t clockName,
                                            uint32_t *frequency)
{
    clock_manager_error_code_t returnCode = kClockManagerSuccess;
    switch (clockName)
    {
    case kCoreClock:
    case kSystemClock:
        *frequency = CLOCK_SYS_GetCoreClockFreq();
        break;
    case kPlatformClock:
        *frequency = CLOCK_SYS_GetSystemClockFreq();
        break;
    case kBusClock:
        *frequency = CLOCK_SYS_GetBusClockFreq();
        break;
    case kFlashClock:
        *frequency = CLOCK_SYS_GetFlashClockFreq();
        break;
    case kOsc32kClock:
        *frequency = CLOCK_SYS_GetExternalRefClock32kFreq();
        break;
    case kOsc0ErClock:
        *frequency = CLOCK_SYS_GetOsc0ExternalRefClockFreq();
        break;
    case kIrc48mClock:
        *frequency = kMcgliteConst48M;
        break;
    case kRtcoutClock:
        *frequency = CLOCK_SYS_GetRtcOutFreq();
        break;
    case kMcgOutClock:
        *frequency = CLOCK_HAL_GetOutClk(MCG);
        break;
    case kMcgIrClock:
        *frequency = CLOCK_HAL_GetInternalRefClk(MCG);
        break;
    case kLpoClock:
        *frequency = CLOCK_SYS_GetLpoClockFreq();
        break;
        case kSystickClock:
            *frequency = CLOCK_SYS_GetSystickFreq();
            break;
    default:
        *frequency = 0U;
        returnCode = kClockManagerNoSuchClockName;
        break;
    }
    return returnCode;
}

this function gives you an example!

Wish it helps you!

If you still have question, please let me know!

Have a great day,
Jingjing

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[bobpaddock · Accepted solution]

"MCG_C1 |=" the '|' is the problem, can't have more than one clock selected in C1 at a time.

I use the code below.  Hopefully the editor here does not hose it like it typically does for me:

void clock_usb( void )
{
      /* The SOPT1 register is only reset on POR or LVD: */
      SIM_SOPT1 = (
                  // SIM_SOPT1_USBREGEN_MASK |    /* USB voltage regulator is enabled [Do we need to do this?] */
                  SIM_SOPT1_OSC32KSEL( 3U )        /* LPO 1kHz oscillator drives 32 kHz clock for RTC and LPTMR via ERCLK32K */
                  );

      SIM_SOPT2 = (
                  SIM_SOPT2_TPMSRC(    1U )    | /* 1:IRC48M/MCGPCLK, 2:OSCERCLK, 3:IRC8M/MCGIRCLK: Clock feeds the TPM clock */
                  SIM_SOPT2_LPUART0SRC( 1U )    | /* 1:IRC48M/MCGPCLK, 2:OSCERCLK, 3:IRC8M/MCGIRCLK: Clock feeds LPUART0 baud generator */
                  SIM_SOPT2_LPUART1SRC( 1U )    | /* 1:IRC48M/MCGPCLK, 2:OSCERCLK, 3:IRC8M/MCGIRCLK: Clock feeds LPUART0 baud generator */
                  SIM_SOPT2_CLKOUTSEL(  CLKOUT ) | /* 0:None, 2:Bus, 3:LPO-1kHz, 4:IRC8M/LIRC_CLK, 6:OSCERCLK, 7:IRC48M */
                  SIM_SOPT2_USBSRC_MASK            /* 0:External bypass clock (USB_CLKIN), 1:IRC48M */
                  );
      SIM_SCGC4 |= SIM_SCGC4_USBFS_MASK;            /* Enable USB module clock */
      /*
      * When power on or out of reset, Low-power Internal RC (LIRC) at 8
      * MHz is selected as the main clock source. To select other clock
      * sources, the mode must be set to HIRC before changing to an other
      * mode.
      *
      * Note that the bootloader may have changed clock configuration
      * substantially from the data sheet reset values.
      */
      MCG_MC    = MCG_MC_HIRCEN_MASK;      /* High-frequency IRC Enabled. Enables the HIRC, even when MCG_Lite is not working at HIRC mode */

      MCG_C1    = (
                  MCG_C1_CLKS( 0U )  |    /* 0:HIRC, 1:LIRC2M or LIRC8M mode, 2:External Clock */
                  MCG_C1_IRCLKEN_MASK      /* Internal Reference Clock LIRC enabled */
                  );
      /*
      * Clock Mode Status.  This field does not update immediately after
      * a write to MCG_C1[CLKS] due to domain synchronization.
      *
      * Check MCG_S[CLKST] to confirm HIRC clock source is selected
      */

      while( (0U << MCG_S_CLKST_SHIFT) != MCG_S_CLKST( 0U ) )
        {
          nop();
        }

    #if( defined( USB_VID ) && defined( MCU_MKL27Z4 ) ) /* Only the 43/27 family has USB sync the 25 family does not */
      USB0_USBTRC0            = 0x40U;      /* Attach Coldfire V1 USB peripheral to the bus */
      USB0_CLK_RECOVER_IRC_EN = (USB_CLK_RECOVER_IRC_EN_IRC_EN_MASK|USB_CLK_RECOVER_IRC_EN_REG_EN_MASK); /* Note that bit-0 is reserved and must be set to one, the data sheet does not explain why */
      USB0_CLK_RECOVER_CTRL  = (USB_CLK_RECOVER_CTRL_CLOCK_RECOVER_EN_MASK|USB_CLK_RECOVER_CTRL_RESTART_IFRTRIM_EN_MASK);

      USB0_CLK_RECOVER_INT_STATUS = USB_CLK_RECOVER_INT_STATUS_OVF_ERROR_MASK; /* Combined USB Clock Recovery interrupt status */
      USB0_CLK_RECOVER_INT_EN    = 0U;    /* Is enabled out of reset by default */
    #endif

      /*
      * The MCG_Lite module does not support switch between LIRC 2 MHz
      * and 8 MHz directly, because 2 MHz and 8 MHz clock generators
      * share circuits and logics. To switch between each other, the
      * module must be in HIRC or EXT clock mode.
      *
      * To enter LIRC8M mode from HIRC or EXT mode:
      *    1. 1. Write 0b to MCG_C2[IRCS] to select LIRC 2M.  Write 1b to MCG_C2[IRCS] to select LIRC 8M.
      *    2. Write 1b to MCG_C1[IRCLKEN] to enable LIRC clock (optional).
      *    3. Write 01b to MCG_C1[CLKS] to select LIRC clock source.
      *    4. Check MCG_S[CLKST] to confirm LIRC clock source is selected.
      */

      MCG_C2    = (
                  MCG_C2_IRCS_MASK        /* Low-frequency Internal Reference Clock Select LIRC 8 MHz */
                  );

      MCG_MC    = (MCG_MC_HIRCEN_MASK|MCG_MC_LIRC_DIV2( 1U )); /* High-frequency IRC Enabled.  LIRC/2 = 4MHz to match Bus.  Use MCGIRCLK for peripherals */
}