RT-Thread 27. UART设备
1.实现串口通信
这里实现uart0的485通信
MSH命令输入：uart_data_sample，开启线程执行。
输入一段字符串，以’\r’ （0x0D）结尾，回显输入的字符串
2. 代码
//rt_uart.c
#include //delay.c
#include "delay.h"
//
static uint32_t fac_us=72; //us延时倍乘数
//初始化延迟函数
//当使用ucos的时候,此函数会初始化ucos的时钟节拍
//SYSTICK的时钟固定为AHB时钟的1/8
//SYSCLK:系统时钟频率,MHz
void delay_init(uint8_t SYSCLK)
{
fac_us=SYSCLK;
}
//延时nus
//nus为要延时的us数.
//注意:nus的值不要大于1000us
void delay_us(uint32_t nus)
{
uint32_t ticks;
uint32_t told,tnow,tcnt=0;
uint32_t reload=SysTick->LOAD; //LOAD的值
ticks=nus*fac_us; //需要的节拍数
told=SysTick->VAL; //刚进入时的计数器值
while(1)
{
tnow=SysTick->VAL;
if(tnow!=told)
{
if(tnow<told)tcnt+=told-tnow; //这里注意一下SYSTICK是一个递减的计数器就可以了.
else tcnt+=reload-tnow+told;
told=tnow;
if(tcnt>=ticks)break; //时间超过/等于要延迟的时间,则退出.
}
}
}
#if 1
//延时nms
//nms:要延时的ms数
void delay_ms(uint16_t nms)
{
uint32_t i;
for(i=0; i<nms; i++) delay_us(1000);
}
#endif
//delay.h
#ifndef _DELAY_H
#define _DELAY_H
#include "gd32f3x0.h"
void delay_init(uint8_t SYSCLK);
void delay_ms(uint16_t nms);
void delay_us(uint32_t nus);
#endif
//drv_usart.c
/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021-06-21 RiceChen the first version
*/
#include //drv_usart.h
//增加tx_af，rx_af
/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021-06-20 RiceChen the first version
*/
#ifndef __DRV_USART_H__
#define __DRV_USART_H__
#include //drv_gpio.c
//增加GPIOE的存储位置，不然GPIOF会出错
/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021-06-20 RiceChen the first version
*/
#include //drv_gpio.h
/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2021-06-20 RiceChen the first version
*/
#ifndef __DRV_GPIO_H__
#define __DRV_GPIO_H__
#include "gd32f3x0.h"
#include "gd32f3x0_exti.h"
#define __GD32_PORT(port) GPIO##port
#define GD32_PIN(index, port, pin) {index, RCU_GPIO##port, \
GPIO##port, GPIO_PIN_##pin, \
EXTI_SOURCE_GPIO##port, \
EXTI_SOURCE_PIN##pin}
#define GD32_PIN_DEFAULT {-1, (rcu_periph_enum)0, 0, 0, 0, 0}
#define GET_PIN(PORTx,PIN) (rt_base_t)((16 * ( ((rt_base_t)__GD32_PORT(PORTx) - (rt_base_t)GPIO_BASE)/(0x0400UL) )) + PIN)
struct pin_index
{
rt_int16_t index;
rcu_periph_enum clk;
rt_uint32_t gpio_periph;
rt_uint32_t pin;
rt_uint8_t port_src;
rt_uint8_t pin_src;
};
struct pin_irq_map
{
rt_uint16_t pinbit;
IRQn_Type irqno;
};
#endif
//board.c
/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2009-01-05 Bernard first implementation
*/
#include 3.效果
