【得捷Follow me第4期】PiCO_W5500以太网应用

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【得捷Follow me第4期】PiCO_W5500以太网应用 [复制链接]

### ****[[ 演示视频 ]](https://training.eeworld.com.cn/video/39289 "[ 演示视频 ]")****

Digikey和EEWorld联合举行的FollowMe第四期，本期使用的板卡是WIZnet推出的RP2040搭配W5500开发板PICO W5500。该评估板可用于以太网应用的开发和测试，在其[产品介绍页面](https://docs.wiznet.io/Product/iEthernet/W5500/w5500-evb-pico)详细对其板载的芯片种类、芯片数据手册、评估板原理图和应用示例进行了介绍。

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在Github上有官方提供的代码示例可供参考：
- C/C++ Example
  - [Ethernet Example](https://github.com/Wiznet/RP2040-HAT-C)
  - [AWS Example](https://github.com/Wiznet/RP2040-HAT-AWS-C)
  - [Azure Example](https://github.com/Wiznet/RP2040-HAT-AZURE-C)
  - [Lwip Example](https://github.com/Wiznet/RP2040-HAT-LWIP-C)
  - [FreeRTOS Example](https://github.com/Wiznet/RP2040-HAT-FREERTOS-C)
- [CircuitPython Example](https://github.com/Wiznet/RP2040-HAT-CircuitPython)
- [MicroPython Example](https://github.com/Wiznet/RP2040-HAT-MicroPython)

该评估版给出的资源还是十分丰富，从简单的基础示例到复杂的综合应用都有可以借鉴的代码，学习起来还是很方便的。

# 入门任务开发环境搭建、Blink和串口输出任务
本次活动使用MicroPython作为开发语言，使用的软件位Thonny。Thonny软件的安装很简单，安装选项使用默认即可。

完成安装后，在软件的配置选项中选择使用到的代码解释器类型为MicroPython(Raspberry Pi Pico)。

要想在开发板上运行MicroPython的代码，需要将MicroPython的固件烧写到开发板上。首先从[MicroPython W550_EVB_PICO](https://micropython.org/download/W5500_EVB_PICO/)的发布页面下载对应该开发板的MicroPython固件。

按住开发板上的BootSel按键并上电或者在上电状态下，按住BootSel按键的同时，按下Run按键，开发板会进入BootLoader模式，在电脑上会出现一个RPI-RP2的大容量存储设备。

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将下载的MicroPython固件发送到该设备，会自动完成固件的烧写。打开Thonny软件，在右下角选择显示出来的开发板。

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在Shell中使用`help('modules')`指令可以查看当前固件中支持的函数类。

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编写Blink的代码如下，实现对开发板上的LED灯的控制

```python
from machine import Pin
import time

led = Pin(25, Pin.OUT)

def main():
    while True:
        led.value(1)
        time.sleep(1)
        led.value(0)
        time.sleep(1)

if __name__ == "__main__":
    main()
```

点击工具栏中的Run按键即可运行上述代码，如果想在上电时就运行上述代码，新建一个`main.py`的文件，并上传到设备(这里指的是的pico w5500开发板)的根目录中，这样上电后程序会自动运行Blink的程序。

可以使用`print`函数向Shell输出信息。以下代码实现发送信息的功能。

```python
from machine import Pin
import time

led = Pin(25, Pin.OUT)

def main():
    while True:
        led.value(1)
        print('LED is on!\n')
        time.sleep(1)
        led.value(0)
        print('LED is off!\n')
        time.sleep(1)

if __name__ == "__main__":
    main()
```

运行程序后，在Thonny的Shell串口可以看到发出的信息。

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# 基础任务一：主控板W55500初始化（静态IP配置），ping指令使用和数据包抓取
通过使用help指令可以查看network中包含的类，其中的`WIZNET5K`实现了WIZnet芯片的接口函数。可以很方面地使用板上的W5500外设，实现互联网应用。

通过`import`指令导入以下库，用于开启socket支持、GPIO驱动、SPI驱动、网络函数以及时间函数
```python
from usocket import socket
from machine import Pin,SPI
import network
import time
```

以下代码为W5500的初始化代码，初始化片上的SPI外设以及W5500芯片后，配置网络接口并测试网咯连接是否成功建立，建立成功后，在Shell中输出网卡的配置信息。

```python
#W5x00 chip init
def w5x00_init():
    spi=SPI(0,2_000_000, mosi=Pin(19),miso=Pin(16),sck=Pin(18))
    nic = network.WIZNET5K(spi,Pin(17),Pin(20)) #spi,cs,reset pin
    nic.active(True)
    nic.ifconfig(('192.168.1.20','255.255.255.0','192.168.1.1','8.8.8.8'))
    while not nic.isconnected():
        time.sleep(1)
        print(nic.regs())
    print(nic.ifconfig())
```
接下来定义主函数如下，调用w5500芯片输出化函数，同时在main函数的循环中调用延时和GPIO翻转函数，用于提示系统正在运行。

```python
def main():
    w5x00_init()

while True:
        led.value(1)
        time.sleep(1)
        led.value(0)
        time.sleep(1)

if __name__ == "__main__":
    main()
```

文章[Python中`if __name__=='__main__':的作用](https://blog.csdn.net/heqiang525/article/details/89879056)对代码中的main函数调用规则进行了说明。

将上述代码整合到一起，在Thonny中打开文件并点击运行，可以看到Shell中输出了当前的开发板的静态IP配置信息。

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在Windows中打开PowerShell，使用Ping指令检测与开发板的网络连接是否成功建立。
```Shell
ping 192.168.1.20
```

可以看到有以下的输出，说明W5500芯片正常运行，

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使用wireshark抓取PC端的网络数据流，使用过滤条件`ip.addr=192.168.1.20`对抓取到数据进行过滤，可以得到ping指令的数据报，ping指令属于ICMP协议中的功能。

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从结果中可以看到ping指令发送方和接收方的IP地址，以及其他的数据包信息。
# 基础任务二：主控板建立TCPIP服务器
该任务选择使用TCP功能进行实现服务器，Http应用使用的就是TCP协议，嵌入式的Web点灯是嵌入式终端作为HTTP Server，响应PC端的HTTP请求，从而实现网页控制板卡上的LED灯状态。

基础任务一实现了初始化W5500的函数和LED控制函数，在此基础上添加一个网页初始化函数，生成用于客户端显示的HTML网页。代码如下：

```python
def web_page():
    if led.value()==1:
        led_state="ON"
    else:
        led_state="OFF"
        
    html = """
    <!DOCTYPE html>
    <html lang="en">
    <head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Raspberry Pi Pico Web server - WIZnet W5100S</title>
    </head>
    <body>
    <div align="center">
    <H1>Raspberry Pi Pico Web server & WIZnet Ethernet HAT</H1>
    <h2>Control LED</h2>
    PICO LED state: <strong>""" + led_state + """</strong>
    <p><a href="/?led=on"><button class="button">ON</button></a>
    </p>
    <p><a href="/?led=off"><button class="button button2">OFF</button></a>
    </p>
    </div>
    </body>
    </html>
    """
    return html
```

在主函数中创建一个socket，用于监听IP地址为192.168.1.20(这里为W5500的IP地址)网卡的端口80，在主循环中，在接收到PC端的客户端请求数据后，发送HTML数据，在接收到返回的数据后，检查其中是否有led_on或者led_off按钮对应的响应数据，据此改变板卡上LED灯的状态。

```python
def main():
    w5x00_init()
    s = socket()
    s.bind(('192.168.1.20', 80))
    s.listen(5)

while True:
        conn, addr = s.accept()
        print('Connect from %s' % str(addr))
        request = conn.recv(1024)
        request = str(request)
        #print('Content = %s' % request)
        led_on = request.find('/?led=on')
        led_off = request.find('/?led=off')
        if led_on == 6:
            print("LED ON")
            led.value(1)
        if led_off == 6:
            print("LED OFF")
            led.value(0)
        response = web_page()
        conn.send('HTTP/1.1 200 OK\n')
        conn.send('Connection: close\n')
        conn.send('Content-Type: text/html\n')
        conn.send('Content-Length: %s\n\n' % len(response))
        conn.send(response)
        conn.close()

if __name__ == "__main__":
    main()
```

整合上述的代码并运行后，可以看到Shell中输出了相应的配置信息。

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在PC端使用浏览器在对话框中输入`192.168.1.20`即可访问控制页面,点击页面上的按钮，即可实现对板卡上的LED灯控制。

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使用WireShark捕获网口的通讯数据，添加`ip.addr=192.168.1.20`过滤出其中数据，可以看到传输的数据为TCP协议数据。

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# 进阶任务：访问NTP服务器同步时间，获取时间并显示
NTP服务全称为Network Time Protocol，协议中定义了客户端和服务器两个用于数据交互的对象，客户端通过向服务器发送包含符合NTP协议要求的网络数据包，在服务器响应请求并返回相应的数据包之后，根据NTP协议解析其中的数据，即可得到需要的时间信息。

在Shell中输入`help('modules')`指令可以看到固件中已经包含了ntptime库，可以直接调用其中的ntp接口函数来获取当前的时间。

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```python
import ntptime
import time

def sync_ntp():
     ntptime.host = 'ntp1.aliyun.com'
     ntptime.settime()
  
def main():
    now = time.time()

t = time.localtime(now)
    
    year, month, day, hour, minute, second, *_ = t
    time_str = f"{year}-{month:02d}-{day:02d} {hour:02d}:{minute:02d}:{second:02d}"

print("时间：", time_str)

if __name__ == "__main__":
    main()
```
时间的数据效果如下图所示。

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# 终极任务：实现FTP服务器
FTP全称为[File Transfer Protocol](https://en.wikipedia.org/wiki/Network_Time_Protocol)，用于在网络中实现服务器与客户端的文件传输。

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在开发板上实现FTP服务器的应用，借鉴已有的MicroPython实现FTP协议的示例，完成FTP服务器的搭建。ftpServer.py如下所示：

```python
#
# Small ftp server for ESP8266 ans ESP32 Micropython
#
# Based on the work of chrisgp - Christopher Popp and pfalcon - Paul Sokolovsky
#
# The server accepts passive mode only.
# It runs in foreground and quits, when it receives a quit command
# Start the server with:
#
# import ftp
#
# Copyright (c) 2016 Christopher Popp (initial ftp server framework)
# Copyright (c) 2016 Robert Hammelrath (putting the pieces together
# and a few extensions)
# Distributed under MIT License
#
import socket
import network
import uos
import gc

def send_list_data(path, dataclient, full):
    try:  # whether path is a directory name
        for fname in sorted(uos.listdir(path), key=str.lower):
            dataclient.sendall(make_description(path, fname, full))
    except:  # path may be a file name or pattern
        pattern = path.split("/")[-1]
        path = path[:-(len(pattern) + 1)]
        if path == "":
            path = "/"
        for fname in sorted(uos.listdir(path), key=str.lower):
            if fncmp(fname, pattern):
                dataclient.sendall(make_description(path, fname, full))

def make_description(path, fname, full):
    if full:
        stat = uos.stat(get_absolute_path(path, fname))
        file_permissions = ("drwxr-xr-x"
                            if (stat[0] & 0o170000 == 0o040000)
                            else "-rw-r--r--")
        file_size = stat[6]
        description = "{}    1 owner group {:>10} Jan 1 2000 {}\r\n".format(
                file_permissions, file_size, fname)
    else:
        description = fname + "\r\n"
    return description

def send_file_data(path, dataclient):
    with open(path, "rb") as file:
        chunk = file.read(512)
        while len(chunk) > 0:
            dataclient.sendall(chunk)
            chunk = file.read(512)

def save_file_data(path, dataclient):
    with open(path, "wb") as file:
        chunk = dataclient.recv(512)
        while len(chunk) > 0:
            file.write(chunk)
            chunk = dataclient.recv(512)

def get_absolute_path(cwd, payload):
    # Just a few special cases "..", "." and ""
    # If payload start's with /, set cwd to /
    # and consider the remainder a relative path
    if payload.startswith('/'):
        cwd = "/"
    for token in payload.split("/"):
        if token == '..':
            if cwd != '/':
                cwd = '/'.join(cwd.split('/')[:-1])
                if cwd == '':
                    cwd = '/'
        elif token != '.' and token != '':
            if cwd == '/':
                cwd += token
            else:
                cwd = cwd + '/' + token
    return cwd

# compare fname against pattern. Pattern may contain
# wildcards ? and *.
def fncmp(fname, pattern):
    pi = 0
    si = 0
    while pi < len(pattern) and si < len(fname):
        if (fname[si] == pattern[pi]) or (pattern[pi] == '?'):
            si += 1
            pi += 1
        else:
            if pattern[pi] == '*':  # recurse
                if (pi + 1) == len(pattern):
                    return True
                while si < len(fname):
                    if fncmp(fname[si:], pattern[pi+1:]):
                        return True
                    else:
                        si += 1
                return False
            else:
                return False
    if pi == len(pattern.rstrip("*")) and si == len(fname):
        return True
    else:
        return False

def ftpserver(net, port=21, timeout=None):

DATA_PORT = 13333

ftpsocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    datasocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

ftpsocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    datasocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

ftpsocket.bind(socket.getaddrinfo("0.0.0.0", port)[0][4])
    datasocket.bind(socket.getaddrinfo("0.0.0.0", DATA_PORT)[0][4])

ftpsocket.listen(1)
    ftpsocket.settimeout(timeout)
    datasocket.listen(1)
    datasocket.settimeout(None)

msg_250_OK = '250 OK\r\n'
    msg_550_fail = '550 Failed\r\n'
    addr = net.ifconfig()[0]
    print("FTP Server started on ", addr)
    try:
        dataclient = None
        fromname = None
        do_run = True
        while do_run:
            cl, remote_addr = ftpsocket.accept()
            cl.settimeout(300)
            cwd = '/'
            try:
                # print("FTP connection from:", remote_addr)
                cl.sendall("220 Hello, this is Micropython.\r\n")
                while True:
                    gc.collect()
                    data = cl.readline().decode("utf-8").rstrip("\r\n")
                    if len(data) <= 0:
                        print("Client disappeared")
                        do_run = False
                        break

command = data.split(" ")[0].upper()
                    payload = data[len(command):].lstrip()

path = get_absolute_path(cwd, payload)

print("Command={}, Payload={}".format(command, payload))

if command == "USER":
                        cl.sendall("230 Logged in.\r\n")
                    elif command == "SYST":
                        cl.sendall("215 UNIX Type: L8\r\n")
                    elif command == "NOOP":
                        cl.sendall("200 OK\r\n")
                    elif command == "FEAT":
                        cl.sendall("211 no-features\r\n")
                    elif command == "PWD" or command == "XPWD":
                        cl.sendall('257 "{}"\r\n'.format(cwd))
                    elif command == "CWD" or command == "XCWD":
                        try:
                            files = uos.listdir(path)
                            cwd = path
                            cl.sendall(msg_250_OK)
                        except:
                            cl.sendall(msg_550_fail)
                    elif command == "CDUP":
                        cwd = get_absolute_path(cwd, "..")
                        cl.sendall(msg_250_OK)
                    elif command == "TYPE":
                        # probably should switch between binary and not
                        cl.sendall('200 Transfer mode set\r\n')
                    elif command == "SIZE":
                        try:
                            size = uos.stat(path)[6]
                            cl.sendall('213 {}\r\n'.format(size))
                        except:
                            cl.sendall(msg_550_fail)
                    elif command == "QUIT":
                        cl.sendall('221 Bye.\r\n')
                        do_run = False
                        break
                    elif command == "PASV":
                        cl.sendall('227 Entering Passive Mode ({},{},{}).\r\n'.
                                   format(addr.replace('.', ','), DATA_PORT >> 8,
                                          DATA_PORT % 256))
                        dataclient, data_addr = datasocket.accept()
                        print("FTP Data connection from:", data_addr)
                        DATA_PORT = 13333
                        active = False
                    elif command == "PORT":
                        items = payload.split(",")
                        if len(items) >= 6:
                            data_addr = '.'.join(items[:4])
                            # replace by command session addr
                            if data_addr == "127.0.1.1":
                                data_addr = remote_addr
                            DATA_PORT = int(items[4]) * 256 + int(items[5])
                            dataclient = socket.socket(socket.AF_INET,
                                                       socket.SOCK_STREAM)
                            dataclient.settimeout(10)
                            dataclient.connect((data_addr, DATA_PORT))
                            print("FTP Data connection with:", data_addr)
                            cl.sendall('200 OK\r\n')
                            active = True
                        else:
                            cl.sendall('504 Fail\r\n')
                    elif command == "LIST" or command == "NLST":
                        if not payload.startswith("-"):
                            place = path
                        else:
                            place = cwd
                        try:
                            cl.sendall("150 Here comes the directory listing.\r\n")
                            send_list_data(place, dataclient,
                                           command == "LIST" or payload == "-l")
                            cl.sendall("226 Listed.\r\n")
                        except:
                            cl.sendall(msg_550_fail)
                        if dataclient is not None:
                            dataclient.close()
                            dataclient = None
                    elif command == "RETR":
                        try:
                            cl.sendall("150 Opening data connection.\r\n")
                            send_file_data(path, dataclient)
                            cl.sendall("226 Transfer complete.\r\n")
                        except:
                            cl.sendall(msg_550_fail)
                        if dataclient is not None:
                            dataclient.close()
                            dataclient = None
                    elif command == "STOR":
                        try:
                            cl.sendall("150 Ok to send data.\r\n")
                            save_file_data(path, dataclient)
                            cl.sendall("226 Transfer complete.\r\n")
                        except:
                            cl.sendall(msg_550_fail)
                        if dataclient is not None:
                            dataclient.close()
                            dataclient = None
                    elif command == "DELE":
                        try:
                            uos.remove(path)
                            cl.sendall(msg_250_OK)
                        except:
                            cl.sendall(msg_550_fail)
                    elif command == "RMD" or command == "XRMD":
                        try:
                            uos.rmdir(path)
                            cl.sendall(msg_250_OK)
                        except:
                            cl.sendall(msg_550_fail)
                    elif command == "MKD" or command == "XMKD":
                        try:
                            uos.mkdir(path)
                            cl.sendall(msg_250_OK)
                        except:
                            cl.sendall(msg_550_fail)
                    elif command == "RNFR":
                            fromname = path
                            cl.sendall("350 Rename from\r\n")
                    elif command == "RNTO":
                            if fromname is not None:
                                try:
                                    uos.rename(fromname, path)
                                    cl.sendall(msg_250_OK)
                                except:
                                    cl.sendall(msg_550_fail)
                            else:
                                cl.sendall(msg_550_fail)
                            fromname = None
                    elif command == "MDTM":
                        try:
                            tm=localtime(uos.stat(path)[8])
                            cl.sendall('213 {:04d}{:02d}{:02d}{:02d}{:02d}{:02d}\r\n'.format(*tm[0:6]))
                        except:
                            cl.sendall('550 Fail\r\n')
                    elif command == "STAT":
                        if payload == "":
                            cl.sendall("211-Connected to ({})\r\n"
                                       "    Data address ({})\r\n"
                                       "211 TYPE: Binary STRU: File MODE:"
                                       " Stream\r\n".format(
                                           remote_addr[0], addr))
                        else:
                            cl.sendall("213-Directory listing:\r\n")
                            send_list_data(path, cl, True)
                            cl.sendall("213 Done.\r\n")
                    else:
                        cl.sendall("502 Unsupported command.\r\n")
                        print("Unsupported command {} with payload {}".format(
                            command, payload))
            except Exception as err:
                print(err)

finally:
                cl.close()
                cl = None
    except Exception as e:
        print(e)
    finally:
        datasocket.close()
        ftpsocket.close()
        if dataclient is not None:
            dataclient.close()

# ftpserver()
```

实际的运行效果,shell端的输出

<ignore_js_op>

<div class="tip tip_4 aimg_tip" id="aimg_789140_menu" style="position: absolute; display: none" disautofocus="true">
<div class="xs0">
<p><strong>FTP_Shell.png</strong> <em class="xg1">(33.39 KB, 下载次数: 0)</em></p>
<p>
<a href="javascript:;" class="loginf" >下载附件</a>

<a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_789140" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=789140&handlekey=savephoto_789140">保存到相册</a>

</p>

</div>
<div class="tip_horn"></div>
</div>

</ignore_js_op>

在FTP客户端可以看到开发板上的文件系统中的文件，并可以对其进行操作。

<ignore_js_op>

<div class="tip tip_4 aimg_tip" id="aimg_789141_menu" style="position: absolute; display: none" disautofocus="true">
<div class="xs0">
<p><strong>FTP_client.png</strong> <em class="xg1">(33.29 KB, 下载次数: 0)</em></p>
<p>
<a href="javascript:;" class="loginf" >下载附件</a>

<a href="javascript:;" onclick="showWindow(this.id, this.getAttribute('url'), 'get', 0);" id="savephoto_789141" url="home.php?mod=spacecp&ac=album&op=saveforumphoto&aid=789141&handlekey=savephoto_789141">保存到相册</a>

</p>

</div>
<div class="tip_horn"></div>
</div>

</ignore_js_op>

# 总结
Follow Me本期使用的PICO_W5500开发板主要集中与以太网应用，ping指令学习了解到ICMP协议的作用以及wireshark的使用，HTTP应用了解到TCP协议的应用，NTP获取时间学习到服务器和客户端的数据通讯方式，FTP应用学习到网络中实现文件传输服务的方法。而且使用micropython已经编译好的固件，省去了开发底层驱动的烦恼，可以专注于TCP协议的学习，作为入门和学习的不二之选。

### [代码包](https://download.eeworld.com.cn/detail/EPTmachine/630302 "代码包")