Pandora IOT development board learning (RT thread) - Experiment 1 LED flashing experiment (learning notes)

This article code reference RT-Thread official BSP

Experimental function

Routine source code ：（main.c）

The experiment realized LED_R The twinkle of , The interval between on and off is 500 ms.

/* * Copyright (c) 2006-2018, RT-Thread Development Team * * SPDX-License-Identifier: Apache-2.0 * * Change Logs: * Date Author Notes * 2018-08-16 armink first implementation */

#include <rtthread.h>
#include <rtdevice.h>
#include <board.h>

#define DBG_TAG "main"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>

/*  To configure  LED  Lamp pin  */
#define LED_PIN PIN_LED_R

int main(void)
{
    
    unsigned int count = 1;

    /*  Set up  LED  Pin is output mode  */
    rt_pin_mode(LED_PIN, PIN_MODE_OUTPUT);

    while (count > 0)
    {
    
        /* LED  Light on  */
        rt_pin_write(LED_PIN, PIN_LOW);
        LOG_D("led on, count: %d", count);
        rt_thread_mdelay(500);

        /* LED  The light goes out  */
        rt_pin_write(LED_PIN, PIN_HIGH);
        LOG_D("led off");
        rt_thread_mdelay(500);

        count++;
    }

    return 0;
}

Code analysis

rt_pin_mode()

The function is to GPIO Pin The initialization , Defined as

/* RT-Thread Hardware PIN APIs */
void rt_pin_mode(rt_base_t pin, rt_base_t mode)
{
    
    RT_ASSERT(_hw_pin.ops != RT_NULL);
    _hw_pin.ops->pin_mode(&_hw_pin.parent, pin, mode);
}

Parameters pin It's a rt_base_t Variable （long), Below GET_PIN() yes STM32 Of pin Value macro definition , Fill in capital letters for the first parameter , The second parameter is filled with numbers .

#define GET_PIN(PORTx,PIN) (rt_base_t)((16 * ( ((rt_base_t)__STM32_PORT(PORTx) - (rt_base_t)GPIOA)/(0x0400UL) )) + PIN)

#define __STM32_PORT(port) GPIO##port // ##  Is a character connector , If  port  by  A, said  GPIOA

For example, in the experiment #define PIN_LED_R GET_PIN(E, 7) , Express GPIOE GPIO_Pin7

at present RT-Thread Supported pin operating modes include ：

#define PIN_MODE_OUTPUT 0x00 /*  Output  */
#define PIN_MODE_INPUT 0x01 /*  Input  */
#define PIN_MODE_INPUT_PULLUP 0x02 /*  Pull up input  */
#define PIN_MODE_INPUT_PULLDOWN 0x03 /*  Drop down input  */
#define PIN_MODE_OUTPUT_OD 0x04 /*  Open drain output  */

stay bsp Of drv_gpio.c In file , There is a bottom layer GPIO drive , Here is STM32 Of GPIO Driver function of mode setting （ You should be familiar with , Just use HAL Library written GPIO Initialization code ）

static void stm32_pin_mode(rt_device_t dev, rt_base_t pin, rt_base_t mode)
{
    
    const struct pin_index *index;
    GPIO_InitTypeDef GPIO_InitStruct;

    index = get_pin(pin);
    if (index == RT_NULL)
    {
    
        return;
    }

    /* Configure GPIO_InitStructure */
    GPIO_InitStruct.Pin = index->pin;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;

    if (mode == PIN_MODE_OUTPUT)
    {
    
        /* output setting */
        GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
        GPIO_InitStruct.Pull = GPIO_NOPULL;
    }
    else if (mode == PIN_MODE_INPUT)
    {
    
        /* input setting: not pull. */
        GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
        GPIO_InitStruct.Pull = GPIO_NOPULL;
    }
    else if (mode == PIN_MODE_INPUT_PULLUP)
    {
    
        /* input setting: pull up. */
        GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
        GPIO_InitStruct.Pull = GPIO_PULLUP;
    }
    else if (mode == PIN_MODE_INPUT_PULLDOWN)
    {
    
        /* input setting: pull down. */
        GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
        GPIO_InitStruct.Pull = GPIO_PULLDOWN;
    }
    else if (mode == PIN_MODE_OUTPUT_OD)
    {
    
        /* output setting: od. */
        GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;
        GPIO_InitStruct.Pull = GPIO_NOPULL;
    }

    HAL_GPIO_Init(index->gpio, &GPIO_InitStruct);
}

rt_pin_write()

GPIO Write function , Here is the definition of the function ,

void rt_pin_write(rt_base_t pin, rt_base_t value)
{
    
    RT_ASSERT(_hw_pin.ops != RT_NULL);
    _hw_pin.ops->pin_write(&_hw_pin.parent, pin, value);
}

and GPIO The mode configuration function is similar , In fact, it will also call the corresponding functions in the underlying driver , The underlying function is through HAL_GPIO_WritePin() To complete GPIO Pin Modification of .

static void stm32_pin_write(rt_device_t dev, rt_base_t pin, rt_base_t value)
{
    
    const struct pin_index *index;

    index = get_pin(pin);
    if (index == RT_NULL)
    {
    
        return;
    }

    HAL_GPIO_WritePin(index->gpio, index->pin, (GPIO_PinState)value);
}

rt_thread_mdelay()

This is a RT-Thread Millisecond delay function , The definition is as follows ：

rt_err_t rt_thread_mdelay(rt_int32_t ms)
{
    
    rt_tick_t tick;

	//  Get the required clock beat 
    tick = rt_tick_from_millisecond(ms);
	
	//  Block the corresponding beat time 
    return rt_thread_sleep(tick);
}

rt_tick_from_millisecond()

/** *  Work out  ms  The number of corresponding clock beats  * * * @param ms the specified millisecond * - Negative Number wait forever * - Zero not wait * - Max 0x7fffffff * * @return the calculated tick */
rt_tick_t rt_tick_from_millisecond(rt_int32_t ms)
{
    
    rt_tick_t tick;

    if (ms < 0)
    {
    
        tick = (rt_tick_t)RT_WAITING_FOREVER;  // -1 
    }
    else
    {
    
    	//  take “ Beats per second ” / 1000 * ms, Calculate the corresponding second beats 
        tick = RT_TICK_PER_SECOND * (ms / 1000);
		
		//  Plus less than  1000ms  Part of the beat number 
        tick += (RT_TICK_PER_SECOND * (ms % 1000) + 999) / 1000;
    }
    
    /* return the calculated tick */
    return tick;
}

rt_thread_sleep()

Thread sleep （ Hang up ） function , The parameter is the number of system beats ：

/** *  This function can make the current thread hang for a period of time （ from  tick  decision ） * * @param tick the sleep ticks * * @return RT_EOK */
rt_err_t rt_thread_sleep(rt_tick_t tick)
{
    
    register rt_base_t temp;
    struct rt_thread *thread;

    /* set to current thread */
    thread = rt_thread_self();
    RT_ASSERT(thread != RT_NULL);
    RT_ASSERT(rt_object_get_type((rt_object_t)thread) == RT_Object_Class_Thread);

    /* disable interrupt */
    temp = rt_hw_interrupt_disable();

    /* suspend thread */
    rt_thread_suspend(thread);

    /* reset the timeout of thread timer and start it */
    rt_timer_control(&(thread->thread_timer), RT_TIMER_CTRL_SET_TIME, &tick);
    rt_timer_start(&(thread->thread_timer));

    /* enable interrupt */
    rt_hw_interrupt_enable(temp);

    rt_schedule();

    /* clear error number of this thread to RT_EOK */
    if (thread->error == -RT_ETIMEOUT)
        thread->error = RT_EOK;

    return RT_EOK;
}

LOG_D()

In this study , We can LOG_D() As rt_kprintf(),

#define dbg_log_line(lvl, color_n, fmt, ...) \ do \ {
       \ _DBG_LOG_HDR(lvl, color_n); \ rt_kprintf(fmt, ##__VA_ARGS__); \ _DBG_LOG_X_END; \ } \ while (0)

LOG_D yes RT-Thread A log printing function in the kernel , Details visible ：《RT-Thread Document center ——ulog journal 》

RT-Thread Log API Include ：