sysinit_nxp_xpresso_812.c

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/*
 * @brief NXP Xpresso LPC812 Sysinit file
 *
 * @note
 * Copyright(C) NXP Semiconductors, 2012
 * All rights reserved.
 *
 * @par
 * Software that is described herein is for illustrative purposes only
 * which provides customers with programming information regarding the
 * LPC products.  This software is supplied "AS IS" without any warranties of
 * any kind, and NXP Semiconductors and its licensor disclaim any and
 * all warranties, express or implied, including all implied warranties of
 * merchantability, fitness for a particular purpose and non-infringement of
 * intellectual property rights.  NXP Semiconductors assumes no responsibility
 * or liability for the use of the software, conveys no license or rights under any
 * patent, copyright, mask work right, or any other intellectual property rights in
 * or to any products. NXP Semiconductors reserves the right to make changes
 * in the software without notification. NXP Semiconductors also makes no
 * representation or warranty that such application will be suitable for the
 * specified use without further testing or modification.
 *
 * @par
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, under NXP Semiconductors' and its
 * licensor's relevant copyrights in the software, without fee, provided that it
 * is used in conjunction with NXP Semiconductors microcontrollers.  This
 * copyright, permission, and disclaimer notice must appear in all copies of
 * this code.
 */

 #include "board.h"

/*****************************************************************************
 * Private types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Public types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Private functions
 ****************************************************************************/

/* Setup system clocking */
STATIC void SystemSetupClocking(void)
{
#if (LPC8XX_USE_XTAL_OSC == 1)
#if (CRYSTAL_MAIN_FREQ_IN >= 15000000)
 Chip_Clock_SetPLLBypass(false, true); /* EXT oscillator >= 15MHz */
#else
 Chip_Clock_SetPLLBypass(false, false); /* EXT oscillator < 15MHz */
#endif

 /* Turn on the SYSOSC by clearing the power down bit */
 Chip_SYSCTL_PowerUp(SYSCTL_SLPWAKE_SYSOSC_PD);

 /* Select the PLL input to the external oscillator */
 Chip_Clock_SetSystemPllSource(SYSCTL_PLLCLKSRC_SYSOSC);

#else
 /* Turn on the IRC by clearing the power down bit */
 Chip_SYSCTL_PowerUp(SYSCTL_SLPWAKE_IRC_PD);

 /* Select the PLL input in the IRC */
 Chip_Clock_SetSystemPllSource(SYSCTL_PLLCLKSRC_IRC);
#endif /* defined(LPC8XX_USE_XTAL_OSC) */

 /* Configure the PLL M and P dividers */
 /* Setup PLL for main oscillator rate (FCLKIN = 12MHz) * 2 = 324Hz
    MSEL = 1 (this is pre-decremented), PSEL = 2 (for P = 4)
    FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 2 = 24MHz
    FCCO = FCLKOUT * 2 * P = 24MHz * 2 * 4 = 192MHz (within FCCO range) */
 Chip_Clock_SetupSystemPLL(1, 2);

 /* Turn on the PLL by clearing the power down bit */
 Chip_SYSCTL_PowerUp(SYSCTL_SLPWAKE_SYSPLL_PD);

 /* Wait for PLL to lock */
 while (!Chip_Clock_IsSystemPLLLocked()) {}

 /* Set system clock divider to 1 */
 Chip_Clock_SetSysClockDiv(1);

 /* Setup FLASH access to 2 clocks (up to 30MHz) */
 Chip_FMC_SetFLASHAccess(FLASHTIM_30MHZ_CPU);

 /* Set main clock source to the system PLL. This will drive 24MHz
    for the main clock and 24MHz for the system clock */
 Chip_Clock_SetMainClockSource(SYSCTL_MAINCLKSRC_PLLOUT);

 /* Select the CLKOUT clocking source */
 Chip_Clock_SetCLKOUTSource(SYSCTL_CLKOUTSRC_MAINSYSCLK, 1);
}

/* Sets up system pin muxing */
STATIC void SystemSetupMuxing(void)
{
#if (LPC8XX_USE_XTAL_OSC == 1)
 /* Use Switch Matrix Tool swm.c file for the Pin Enable 0 variable */
 LPC_SWM->PINENABLE0 = 0xffffff82UL; /* XTALIN + XTALOUT + CLKOUT on PIO0_1 + ACMP_I1 */

 /* Configure the pins for XTALIN/XTALOUT. */
 LPC_IOCON->PIO0_8 &= ~(3 << 3); /* Repeater Mode */
 LPC_IOCON->PIO0_9 &= ~(3 << 3); /* Repeater Mode */

#else
 /* Use Switch Matrix Tool swm.c file for the Pin Enable 0 variable */
 LPC_SWM->PINENABLE0 = 0xffffffb2UL;  /* IRC + CLKOUT on PIO0_1 + ACMP_I1 */
#endif /* (LPC8XX_USE_XTAL_OSC == 1) */

 /* Assign the CLKOUT function to a pin */
 LPC_SWM->PINASSIGN[8] &= ~(0xFE << 16); /* bits 23:16 = PIN0_x := 1 in this case */

 /* Configure the pin for CLKOUT on PIO0_1 */
 LPC_IOCON->PIO0_1 &= ~(3 << 3); /* Repeater Mode */
}

/*****************************************************************************
 * Public functions
 ****************************************************************************/

void SystemInit(void)
{
 /* Booting from FLASH, so remap vector table to FLASH */
 Chip_SYSCTL_Map(REMAP_USER_FLASH_MODE);

 /* Enable the clock to the Switch Matrix */
 Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);

 /* Enable the clock for the IOCON */
 Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_IOCON);

 /* Setup system clocking and muxing */
 SystemSetupMuxing();
 SystemSetupClocking();

 /* Disable the clock to the Switch Matrix to save power */
 Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);

 /* IOCON clock left on, but may be turned off in no other IOCON
    changes are needed */
}