rt-thread-official/bsp/n32g452xx/Libraries/rt_drivers/drv_common.c

/*
 * Copyright (c) 2006-2023, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2021-08-20     breo.com     first version
 */

#include "drv_common.h"
#include "board.h"

#ifdef RT_USING_SERIAL
    #ifdef RT_USING_SERIAL_V2
        #include "drv_usart_v2.h"
    #else
        #include "drv_usart.h"
    #endif
#endif

#ifdef RT_USING_FINSH
#include <finsh.h>
static void reboot(uint8_t argc, char **argv)
{
    rt_hw_cpu_reset();
}
MSH_CMD_EXPORT(reboot, Reboot System);
#endif /* RT_USING_FINSH */

/**
 * This function will delay for some us.
 *
 * @param us the delay time of us
 */
void rt_hw_us_delay(rt_uint32_t us)
{
    rt_uint32_t ticks;
    rt_uint32_t told, tnow, tcnt = 0;
    rt_uint32_t reload = SysTick->LOAD;

    ticks = us * reload / (1000000 / RT_TICK_PER_SECOND);
    told = SysTick->VAL;
    while (1)
    {
        tnow = SysTick->VAL;
        if (tnow != told)
        {
            if (tnow < told)
            {
                tcnt += told - tnow;
            }
            else
            {
                tcnt += reload - tnow + told;
            }
            told = tnow;
            if (tcnt >= ticks)
            {
                break;
            }
        }
    }
}