如何用stm32使用LWIP網(wǎng)絡(luò)協(xié)議棧實(shí)現(xiàn)DHCP客戶端

LWIP是一款開源的嵌入式網(wǎng)絡(luò)協(xié)議棧，支持的功能很多，而且能在多任務(wù)環(huán)境下和單任務(wù)裸機(jī)環(huán)境下跑，今天說(shuō)說(shuō)他的移植過(guò)程，芯片為STM32，網(wǎng)卡為ENC28J60，無(wú)操作系統(tǒng)

首先下載LWIP的源代碼，我下載的是1.4.1的源碼，下載后解壓，文件結(jié)構(gòu)如圖

將這四個(gè)目錄中的文件全部拷貝到工程中，API是一些socket通訊的接口，需要在多任務(wù)的環(huán)境下實(shí)現(xiàn)，core里面存放的內(nèi)核源碼，我們主要使用IPV4，include目錄下是需要包含的目錄，lwip只要求我們包含include目錄，里面的內(nèi)層目錄會(huì)自動(dòng)找到，最后建立的工程目錄如下

好了，此時(shí)源碼已經(jīng)做好，還有需要做的，在include目錄下新建一個(gè)文件夾，必須叫arch，里面存放這幾個(gè)文件，自己新建

文件的具體內(nèi)容如下

cc.h

/*

* Copyright （c） 2001-2003 Swedish Institute of Computer Science.

* All rights reserved.

*

* Redistribution and use in source and binary forms， with or without modification，

* are permitted provided that the following conditions are met：

*

* 1. Redistributions of source code must retain the above copyright notice，

* this list of conditions and the following disclaimer.

* 2. Redistributions in binary form must reproduce the above copyright notice，

* this list of conditions and the following disclaimer in the documentation

* and/or other materials provided with the distribution.

* 3. The name of the author may not be used to endorse or promote products

* derived from this software without specific prior written permission.

*

* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS‘’ AND ANY EXPRESS OR IMPLIED

* WARRANTIES， INCLUDING， BUT NOT LIMITED TO， THE IMPLIED WARRANTIES OF

* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT

* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT， INDIRECT， INCIDENTAL， SPECIAL，

* EXEMPLARY， OR CONSEQUENTIAL DAMAGES （INCLUDING， BUT NOT LIMITED TO， PROCUREMENT

* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE， DATA， OR PROFITS; OR BUSINESS

* INTERRUPTION） HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY， WHETHER IN

* CONTRACT， STRICT LIABILITY， OR TORT （INCLUDING NEGLIGENCE OR OTHERWISE） ARISING

* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE， EVEN IF ADVISED OF THE POSSIBILITY

* OF SUCH DAMAGE.

*

* This file is part of the lwIP TCP/IP stack.

*

* Author： Adam Dunkels

*

*/

#ifndef __CC_H__

#define __CC_H__

#include “cpu.h”

//編譯器無(wú)關(guān)的數(shù)據(jù)類型定義

typedef unsigned char u8_t;

typedef signed char s8_t;

typedef unsigned short u16_t;

typedef signed short s16_t;

typedef unsigned long u32_t;

typedef signed long s32_t;

typedef u32_t mem_ptr_t;

typedef int sys_prot_t;

//lwip調(diào)試的時(shí)候數(shù)據(jù)類型定義

#define U16_F “hu”

#define S16_F “d”

#define X16_F “hx”

#define U32_F “u”

#define S32_F “d”

#define X32_F “x”

#define SZT_F “uz”

//根據(jù)不同的編譯器的符號(hào)定義

#if defined （__ICCARM__）

#define PACK_STRUCT_BEGIN

#define PACK_STRUCT_STRUCT

#define PACK_STRUCT_END

#define PACK_STRUCT_FIELD（x） x

#define PACK_STRUCT_USE_INCLUDES

#elif defined （__CC_ARM）

#define PACK_STRUCT_BEGIN __packed

#define PACK_STRUCT_STRUCT

#define PACK_STRUCT_END

#define PACK_STRUCT_FIELD（x） x

#elif defined （__GNUC__）

#define PACK_STRUCT_BEGIN

#define PACK_STRUCT_STRUCT __attribute__ （（__packed__））

#define PACK_STRUCT_END

#define PACK_STRUCT_FIELD（x） x

#elif defined （__TASKING__）

#define PACK_STRUCT_BEGIN

#define PACK_STRUCT_STRUCT

#define PACK_STRUCT_END

#define PACK_STRUCT_FIELD（x） x

#endif

#define LWIP_PLATFORM_ASSERT（x） //do { if（?。▁）） while（1）; } while（0）

#endif /* __CC_H__ */

cpu.h

/*

* Copyright （c） 2001-2003 Swedish Institute of Computer Science.

* All rights reserved.

*

* Redistribution and use in source and binary forms， with or without modification，

* are permitted provided that the following conditions are met：

*

* 1. Redistributions of source code must retain the above copyright notice，

* this list of conditions and the following disclaimer.

* 2. Redistributions in binary form must reproduce the above copyright notice，

* this list of conditions and the following disclaimer in the documentation

* and/or other materials provided with the distribution.

* 3. The name of the author may not be used to endorse or promote products

* derived from this software without specific prior written permission.

*

* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS‘’ AND ANY EXPRESS OR IMPLIED

* WARRANTIES， INCLUDING， BUT NOT LIMITED TO， THE IMPLIED WARRANTIES OF

* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT

* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT， INDIRECT， INCIDENTAL， SPECIAL，

* EXEMPLARY， OR CONSEQUENTIAL DAMAGES （INCLUDING， BUT NOT LIMITED TO， PROCUREMENT

* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE， DATA， OR PROFITS; OR BUSINESS

* INTERRUPTION） HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY， WHETHER IN

* CONTRACT， STRICT LIABILITY， OR TORT （INCLUDING NEGLIGENCE OR OTHERWISE） ARISING

* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE， EVEN IF ADVISED OF THE POSSIBILITY

* OF SUCH DAMAGE.

*

* This file is part of the lwIP TCP/IP stack.

*

* Author： Adam Dunkels

*

*/

#ifndef __CPU_H__

#define __CPU_H__

//定義cpu的數(shù)據(jù)模式，大端小端

#define BYTE_ORDER LITTLE_ENDIAN

#endif /* __CPU_H__ */

perf.h

#ifndef __PERF_H__

#define __PERF_H__

//用于lwip內(nèi)置的統(tǒng)計(jì)功能

//不使能定義為空就可以了

#define PERF_START /* null definition */

#define PERF_STOP（x） /* null definition */

#endif /* __PERF_H__ */

sys_arch.h

#ifndef __SYS_RTXC_H__

#define __SYS_RTXC_H__

void init_lwip_timer（void）; //初始化LWIP定時(shí)器

u8_t timer_expired（u32_t *last_time，u32_t tmr_interval）; //定時(shí)器超時(shí)判斷

#endif /* __SYS_RTXC_H__ */

sya_arch.c--注意該文件要加入源文件列表中，這是c文件哦

#include “l(fā)wip/debug.h”

#include “l(fā)wip/def.h”

#include “l(fā)wip/sys.h”

#include “l(fā)wip/mem.h”

#include “timerx.h”

//初始化LWIP定時(shí)器

void init_lwip_timer（void）

{

TIM6_Int_Init（1000，719）;//100Khz計(jì)數(shù)頻率，計(jì)數(shù)到100為10ms

}

//為L(zhǎng)WIP提供計(jì)時(shí)

extern u32_t lwip_timer;//lwip 計(jì)時(shí)器，每10ms增加1.

u32_t sys_now（void）

{

return lwip_timer;

}

//定時(shí)器超時(shí)判斷

//last_time：最近時(shí)間

//tmr_interval：定時(shí)器溢出周期

u8_t timer_expired（u32_t *last_time，u32_t tmr_interval）

{

u32_t time;

time = *last_time;

if（（lwip_timer-time）》=tmr_interval）{

*last_time = lwip_timer;

return 1;

}

return 0;

}

可以看到我們定義了定時(shí)器，那么就要修改相關(guān)的定時(shí)器文件，文件如下

timerx.c

#include “timerx.h”

u32 lwip_timer=0;//lwip 計(jì)時(shí)器，每10ms增加1.

//定時(shí)器6中斷服務(wù)程序

void TIM6_IRQHandler（void）

{

if （TIM_GetITStatus（TIM6， TIM_IT_Update） ！= RESET） //檢查指定的TIM中斷發(fā)生與否：TIM 中斷源

{

TIM_ClearITPendingBit（TIM6， TIM_IT_Update ）; //清除TIMx的中斷待處理位：TIM 中斷源

lwip_timer++;//lwip計(jì)時(shí)器增加1

}

}

//基本定時(shí)器6中斷初始化

//這里時(shí)鐘選擇為APB1的2倍，而APB1為36M

//arr：自動(dòng)重裝值。

//psc：時(shí)鐘預(yù)分頻數(shù)

//這里使用的是定時(shí)器3！

void TIM6_Int_Init（u16 arr，u16 psc）

{

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd（RCC_APB1Periph_TIM6， ENABLE）; //時(shí)鐘使能

TIM_TimeBaseStructure.TIM_Period = arr; //設(shè)置在下一個(gè)更新事件裝入活動(dòng)的自動(dòng)重裝載寄存器周期的值 計(jì)數(shù)到5000為500ms

TIM_TimeBaseStructure.TIM_Prescaler =psc; //設(shè)置用來(lái)作為TIMx時(shí)鐘頻率除數(shù)的預(yù)分頻值 10Khz的計(jì)數(shù)頻率

TIM_TimeBaseStructure.TIM_ClockDivision = 0; //設(shè)置時(shí)鐘分割：TDTS = Tck_tim

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM向上計(jì)數(shù)模式

TIM_TimeBaseInit（TIM6， &TIM_TimeBaseStructure）; //根據(jù)TIM_TimeBaseInitStruct中指定的參數(shù)初始化TIMx的時(shí)間基數(shù)單位

TIM_ITConfig（ TIM6，TIM_IT_Update“TIM_IT_Trigger，ENABLE）;//使能定時(shí)器6更新觸發(fā)中斷

TIM_Cmd（TIM6， ENABLE）; //使能TIMx外設(shè)

NVIC_InitStructure.NVIC_IRQChannel = TIM6_IRQn; //TIM3中斷

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1; //先占優(yōu)先級(jí)0級(jí)

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2; //從優(yōu)先級(jí)3級(jí)

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道被使能

NVIC_Init（&NVIC_InitStructure）; //根據(jù)NVIC_InitStruct中指定的參數(shù)初始化外設(shè)NVIC寄存器