rt-thread-official/bsp/nuvoton_nuc472/drivers/board.c

/*
 * File      : board.c
 * This file is part of RT-Thread RTOS
 *
 * The license and distribution terms for this file may be
 * found in the file LICENSE in this distribution or at
 * http://www.rt-thread.org/license/LICENSE
 *
 * Change Logs:
 * Date           Author       Notes
 * 2017-12-12     Bluebear233  first implementation
 */

#include <rtconfig.h>
#include <rtthread.h>
#include <board.h>
#include <usart.h>
#include <NUC472_442.h>

#ifdef __CC_ARM
extern int Image$$RW_IRAM1$$ZI$$Limit;
#elif __ICCARM__
#pragma section="HEAP"
#else
extern int __bss_end;
#endif

/**
 * This function will initial Clock tree.
 */
void clock_init(void)
{

    /*---------------------------------------------------------------------------------------------------------*/
    /* Init System Clock                                                                                       */
    /*---------------------------------------------------------------------------------------------------------*/
    /* Unlock protected registers */
    SYS_UnlockReg();

    /* Enable External XTAL (4~24 MHz) */
    CLK_EnableXtalRC(CLK_PWRCTL_HXTEN_Msk);

    /* Waiting for 12MHz clock ready */
    CLK_WaitClockReady( CLK_STATUS_HXTSTB_Msk);

    /* Switch HCLK clock source to HXT */
    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_HXT,CLK_CLKDIV0_HCLK(1));

    /* Set PLL to power down mode and PLL_STB bit in CLKSTATUS register will be cleared by hardware.*/
    CLK->PLLCTL |= CLK_PLLCTL_PD_Msk;

    /* Set PLL frequency */
    CLK->PLLCTL = CLK_PLLCTL_84MHz_HXT;

    /* Waiting for clock ready */
    CLK_WaitClockReady(CLK_STATUS_PLLSTB_Msk);

    /* Switch HCLK clock source to PLL */
    CLK_SetHCLK(CLK_CLKSEL0_HCLKSEL_PLL,CLK_CLKDIV0_HCLK(1));

    /* Update System Core Clock */
    /* User can use SystemCoreClockUpdate() to calculate SystemCoreClock. */
    SystemCoreClockUpdate();

    /* Lock protected registers */
    SYS_LockReg();
}

/**
 * This function will initial NUC472 board.
 */
void rt_hw_board_init(void)
{
    clock_init();

#ifdef RT_USING_HEAP
#ifdef __CC_ARM
    rt_system_heap_init((void*)&Image$$RW_IRAM1$$ZI$$Limit, (void*)SRAM_END);
#elif __ICCARM__
    rt_system_heap_init(__segment_end("HEAP"), (void*)SRAM_END);
#else
    /* init memory system */
    rt_system_heap_init((void*)&__bss_end, (void*)SRAM_END);
#endif
#endif /* RT_USING_HEAP */

    rt_hw_usart_init();

    rt_console_set_device(RT_CONSOLE_DEVICE_NAME);

    SysTick_Config(SystemCoreClock / RT_TICK_PER_SECOND);
}

/**
 * This is the timer interrupt service routine.
 *
 */
void SysTick_Handler(void)
{
    /* enter interrupt */
    rt_interrupt_enter();

    rt_tick_increase();

    /* leave interrupt */
    rt_interrupt_leave();
}