【得捷电子Follow me第4期】进阶任务：从NTP服务器获取时间并显示

alanlan86

【得捷电子Follow me第4期】进阶任务：从NTP服务器获取时间并显示 [复制链接]

<i class="pstatus"> 本帖最后由 alanlan86 于 2024-2-24 21:56 编辑 </i>

# 任务目标
- 通过Pico + W5500 EVB的以太网访问NTP服务器，获取到当前时间，并通过log打印和显示到OLED上
![](http://docs.wiznet.io/assets/images/w5500_evb_pico_side-da676c5d9c41adedc0469b9f1810b81b.png)

# 理论
NTP(Network Time Protocol）网络时间协议基于UDP，用于网络时间同步的协议，使网络中的计算机时钟同步到UTC，再配合各个时区的偏移调整就能实现精准同步对时功能。
【关于如何保证精准同步对时，是一个更深入的内容，此处不展开。感兴趣的可以网络查阅相关资料】

NTP（Network Time Protocol）协议使用UDP（User Datagram Protocol，用户数据报协议）进行数据包传输，其标准端口号是123。客户端在与NTP服务器交互时，会向NTP服务器的123端口发送请求；而当NTP服务器回应时，也会使用UDP协议的源端口123来返回应答。

- 基于这个本质Pico W5500需要先建立一个UDP的连接，访问一个NTP服务器。本任务选用了“ntp.aliyun.com”

- 关于NTP帧格式：
![](https://img-blog.csdn.net/20180811164243878?watermark/2/text/aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Rvc3RoaW5n/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70)

- 详细查看adafruit_wiznet5k库代码adafruit_wiznet5k_ntp.py

1. NTP初始化建立套接字socket

```python
 def __init__(self, iface, ntp_address,utc,debug=False):
        self._debug = debug
        self._iface = iface
        socket.set_interface(self._iface)
        self._sock = socket.socket(type=socket.SOCK_DGRAM)
        self._sock.settimeout(1)
        self._utc = utc

self._ntp_server = ntp_address
        self._host = 0
        self._request_id = 0  # request identifier

self._pkt_buf_ = bytearray()
```
2. 构建包头

```python
    def _build_ntp_header(self,ip):
        self._pkt_buf_.append(0x23)

for i in range(55):
            self._pkt_buf_.append(0x00)
```
3. 绑定端口并发送UDP请求到NTP服务器，并接收返回，从而返回日历时间。

```python
def get_time(self):
        self._build_ntp_header(self._ntp_server)
        self._sock.bind((None,50001))
        self._sock.sendto(self._pkt_buf_,(self._ntp_server, 123))
        while True:
            data = self._sock.recv(1024)
            if data:
                sec = data[40:44]
                int_cal = int.from_bytes(sec,"big")
                cal =int_cal - 2208988800 + self._utc *3600
                cal = time.localtime(cal)
                return cal

```

# 硬件
硬件连接部分继续采用Grove shield的底板和I2C接口的0.96inch的OLED屏幕。
![](https://bbs.eeworld.com.cn/data/attachment/forum/202306/26/193646ezvqvpqtvvao83qs.png.thumb.jpg)

# 软件

## OLED显示

- 显示时间和日期

```python
# 显示日期
    #splash.remove(text_area)
    splash.pop()
    text = "%s"%days[cal.tm_wday+1] +"/"+  str(cal.tm_mday) +"-"+ str(cal.tm_mon) +"-"+ str(cal.tm_year)
    text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=16, y=HEIGHT // 2 - 1)
    splash.append(text_area)
    display.show(splash)
    
    led.value = not led.value
    time.sleep(3)

# 显示时间
    #splash.remove(text_area)
    splash.pop()
    text = "%02d"%cal.tm_hour+":%02d"%cal.tm_min+":%02d"%cal.tm_sec
    text_area = label.Label(
        terminalio.FONT, text=text, color=0xFFFFFF, x=16, y=HEIGHT // 2 - 1
    )
    splash.append(text_area)
    display.show(splash)
```
## NTP获取时间

- 通过get time直接得到日期和时间。

```python
#------------------------------------------------------------------------------
ntpserver_ip = eth.pretty_ip(eth.get_host_by_name("ntp.aliyun.com"))

print("NTP : %s" % ntpserver_ip)  #DNS Domain

ntp = NTP(iface = eth, ntp_address =ntpserver_ip ,utc=8)
cal = ntp.get_time()
print("The date is %s %d/%d/%d" %(days[cal.tm_wday+1], cal.tm_mday,cal.tm_mon,cal.tm_year))
print("The time is %d:%02d:%02d" %(cal.tm_hour,cal.tm_min,cal.tm_sec))

```
## 循环获取时间
- 针对circuitpython库中NTP的调用，若需要循环获取时间，需要增加一个updat time函数。因为已经bind的sokcet是没法再次调用的，因此直接调用sendto函数进行请求发送即可。

```python
def update_time(self):
        #self._build_ntp_header(self._ntp_server)
        #self._sock.bind((None,50001))
        self._sock.sendto(self._pkt_buf_,(self._ntp_server, 123))
        while True:
            data = self._sock.recv(1024)
            if data:
                sec = data[40:44]
                int_cal = int.from_bytes(sec,"big")
                cal =int_cal - 2208988800 + self._utc *3600
                cal = time.localtime(cal)
                return cal
```

## 完整代码

```python
import board
import busio
import digitalio
import time
import adafruit_requests as requests
from adafruit_wiznet5k.adafruit_wiznet5k import *
import adafruit_wiznet5k.adafruit_wiznet5k_socket as socket
from adafruit_wiznet5k.adafruit_wiznet5k_ntp import NTP
import adafruit_wiznet5k.adafruit_wiznet5k_dns as dns
days = ("Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday")

import displayio
import terminalio
from adafruit_display_text import label
import adafruit_displayio_ssd1306

displayio.release_displays()

# Use for I2C
i2c = busio.I2C(scl=board.GP7, sda=board.GP6)
display_bus = displayio.I2CDisplay(i2c, device_address=0x3C)

WIDTH = 128
HEIGHT = 32  # Change to 64 if needed
BORDER = 5

display = adafruit_displayio_ssd1306.SSD1306(display_bus, width=WIDTH, height=HEIGHT)

# Make the display context
splash = displayio.Group()
display.root_group = splash

color_bitmap = displayio.Bitmap(WIDTH, HEIGHT, 1)
color_palette = displayio.Palette(1)
color_palette[0] = 0xFFFFFF  # White

bg_sprite = displayio.TileGrid(color_bitmap, pixel_shader=color_palette, x=0, y=0)
splash.append(bg_sprite)

# Draw a smaller inner rectangle
inner_bitmap = displayio.Bitmap(WIDTH - BORDER * 2, HEIGHT - BORDER * 2, 1)
inner_palette = displayio.Palette(1)
inner_palette[0] = 0x000000  # Black
inner_sprite = displayio.TileGrid(inner_bitmap, pixel_shader=inner_palette, x=BORDER, y=BORDER)
splash.append(inner_sprite)

# Draw a label
text = "Hello World!"
text_area = label.Label(
    terminalio.FONT, text=text, color=0xFFFFFF, x=28, y=HEIGHT // 2 - 1
)
splash.append(text_area)

time.sleep(1)

##SPI0
SPI0_SCK = board.GP18
SPI0_TX = board.GP19
SPI0_RX = board.GP16
SPI0_CSn = board.GP17

##reset
W5x00_RSTn = board.GP20

print("Wiznet5k NTP Test (DHCP)")

# Setup your network configuration below
# random MAC, later should change this value on your vendor ID
MY_MAC = (0x00, 0x01, 0x02, 0x03, 0x04, 0x05)
IP_ADDRESS = (192, 168, 1, 102)
SUBNET_MASK = (255, 255, 255, 0)
GATEWAY_ADDRESS = (192, 168, 1, 1)
#DNS_SERVER = (8, 8, 8, 8) #google公共DNS服务器
DNS_SERVER = (114, 114, 114, 114) #114DNS

led = digitalio.DigitalInOut(board.GP25)
led.direction = digitalio.Direction.OUTPUT

ethernetRst = digitalio.DigitalInOut(W5x00_RSTn)
ethernetRst.direction = digitalio.Direction.OUTPUT

# For Adafruit Ethernet FeatherWing
cs = digitalio.DigitalInOut(SPI0_CSn)
# For Particle Ethernet FeatherWing
# cs = digitalio.DigitalInOut(board.D5)
spi_bus = busio.SPI(SPI0_SCK, MOSI=SPI0_TX, MISO=SPI0_RX)

# Reset W5500 first
ethernetRst.value = False
time.sleep(1)
ethernetRst.value = True

# Initialize ethernet interface with DHCP
#eth = WIZNET5K(spi_bus, cs)
# Initialize ethernet interface without DHCP
#eth = WIZNET5K(spi_bus, cs, is_dhcp=False, mac=MY_MAC)
# Set network configuration
#eth.ifconfig = (IP_ADDRESS, SUBNET_MASK, GATEWAY_ADDRESS, DNS_SERVER)

eth = WIZNET5K(spi_bus, cs, is_dhcp=True, mac=MY_MAC, debug=False)

print("Chip Version:", eth.chip)
print("MAC Address:", [hex(i) for i in eth.mac_address])
print("My IP address is:", eth.pretty_ip(eth.ip_address))

# 显示IP地址
#splash.remove(text_area)
splash.pop()
text = "IP:" + eth.pretty_ip(eth.ip_address)
text_area = label.Label(
    terminalio.FONT, text=text, color=0xFFFFFF, x=16, y=HEIGHT // 2 - 1
)
splash.append(text_area)
display.show(splash)

#------------------------------------------------------------------------------
ntpserver_ip = eth.pretty_ip(eth.get_host_by_name("ntp.aliyun.com"))

print("NTP : %s" % ntpserver_ip)  #DNS Domain

ntp = NTP(iface = eth, ntp_address =ntpserver_ip ,utc=8)
cal = ntp.get_time()
print("The date is %s %d/%d/%d" %(days[cal.tm_wday+1], cal.tm_mday,cal.tm_mon,cal.tm_year))
print("The time is %d:%02d:%02d" %(cal.tm_hour,cal.tm_min,cal.tm_sec))

while True:    
    cal = ntp.update_time()
    print("The date is %s %d/%d/%d" %(days[cal.tm_wday+1], cal.tm_mday,cal.tm_mon,cal.tm_year))
    print("The time is %d:%02d:%02d" %(cal.tm_hour,cal.tm_min,cal.tm_sec))

# 显示日期
    #splash.remove(text_area)
    splash.pop()
    text = "%s"%days[cal.tm_wday+1] +"/"+  str(cal.tm_mday) +"-"+ str(cal.tm_mon) +"-"+ str(cal.tm_year)
    text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=16, y=HEIGHT // 2 - 1)
    splash.append(text_area)
    display.show(splash)
    
    led.value = not led.value
    time.sleep(3)

# 显示时间
    #splash.remove(text_area)
    splash.pop()
    text = "%02d"%cal.tm_hour+":%02d"%cal.tm_min+":%02d"%cal.tm_sec
    text_area = label.Label(
        terminalio.FONT, text=text, color=0xFFFFFF, x=16, y=HEIGHT // 2 - 1
    )
    splash.append(text_area)
    display.show(splash)
        
    led.value = not led.value
    time.sleep(3)

#--------------------------------------------------------------------------------------

```

# 调试
- 通过MuEditor的调试数据信息，可以看到NTP服务器返回的日期和时间信息。

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# 演示视频

# 总结

在了解了NTP的原理后，就可以通过简单的调用cirucitpython的简单几行代码，即可以实现从网络获取到UTC时间，进而可以进行RTC的设置或者网络校时功能，真正的简单方便！！！