rt-thread-official/bsp/lpc824/Libraries/common/chip/sysinit_8xx.c

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/*
* @brief LPC8xx Chip specific SystemInit
*
* @note
* Copyright(C) NXP Semiconductors, 2013
* 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.
*/
#define _CHIP_COMMON_
#include "board_lpc.h"
/*****************************************************************************
* Private types/enumerations/variables
****************************************************************************/
/*****************************************************************************
* Public types/enumerations/variables
****************************************************************************/
/*****************************************************************************
* Private functions
****************************************************************************/
#define CONFIG_MAIN_FREQ 60000000
#define CONFIG_SYS_FREQ MAX_CLOCK_FREQ
/*****************************************************************************
* Public functions
****************************************************************************/
/* Setup system clocking */
void Chip_SetupXtalClocking(void)
{
/* EXT oscillator < 15MHz */
Chip_Clock_SetPLLBypass(false, false);
/* 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);
/* Setup FLASH access to 2 clocks (up to 30MHz) */
Chip_FMC_SetFLASHAccess(FLASHTIM_30MHZ_CPU);
/* Power down PLL to change the PLL divider ratio */
Chip_SYSCTL_PowerDown(SYSCTL_SLPWAKE_SYSPLL_PD);
/* Configure the PLL M and P dividers */
/* Setup PLL for main oscillator rate ((FCLKIN = 12MHz) * 5)/2 = 30MHz */
Chip_Clock_SetupSystemPLL(4, 1);
/* Turn on the PLL by clearing the power down bit */
Chip_SYSCTL_PowerUp(SYSCTL_SLPWAKE_SYSPLL_PD);
/* Enable the clock to the Switch Matrix */
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);
/* Wait for PLL to lock */
while (!Chip_Clock_IsSystemPLLLocked()) {}
Chip_Clock_SetSysClockDiv(2);
/* 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);
}
/* Set up and initialize hardware prior to call to main */
void Chip_SetupIrcClocking(void)
{
Chip_IRC_SetFreq(CONFIG_MAIN_FREQ, CONFIG_SYS_FREQ);
}
/* Set up and initialize hardware prior to call to main */
/* <20><>main()<29><><EFBFBD><EFBFBD>֮ǰ<D6AE><C7B0><EFBFBD>ô˺<C3B4><CBBA><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ij<EFBFBD>ʼ<EFBFBD><CABC><EFBFBD><EFBFBD><EFBFBD><EFBFBD> */
void SystemInit(void)
{
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_IOCON);
#ifdef USE_IRC_AS_ROOT_CLOCK
/* Use 12MHz IRC as clock source */
Chip_SetupIrcClocking();
#else
/* Use Xtal or external clock_in as clock source*/
Chip_Clock_EnablePeriphClock(SYSCTL_CLOCK_SWM);
Chip_SWM_EnableFixedPin(SWM_FIXED_XTALIN);
Chip_SWM_EnableFixedPin(SWM_FIXED_XTALOUT);
// Chip_Clock_DisablePeriphClock(SYSCTL_CLOCK_SWM);
Chip_IOCON_PinSetMode(LPC_IOCON, IOCON_PIO8, PIN_MODE_INACTIVE);
Chip_IOCON_PinSetMode(LPC_IOCON, IOCON_PIO9, PIN_MODE_INACTIVE);
Chip_SetupXtalClocking();
#endif
}