Linux 如何配置无线网络

本文详细介绍了如何使用wpa_supplicant工具配置无线网络,包括全局配置、选择AP和连接不同类型的无线网络,提供了丰富的配置示例和命令执行说明。

前您可以使用我们提供的wireless-tools 或wpa_supplicant工具来配置无线网络。请记住重要的一点是,您对无线网络的配置是全局性的,而非针对具体的接口。

wpa_supplicant是一个最好的选择,但缺点是它不支持所有的驱动。请浏览wpa_supplicant网站获得它所支持的驱动列表。另外,wpa_supplicant目前只能连接到那些你已经配置好ESSID的无线网络。

wireless-tools支持几乎所有的无线网卡和驱动,但它不能连接到那些只支持WPA的AP。


WPA Supplicant工具包可以让您连接到那些使用WPA的AP。因为还只是beta版,所以它的配置方法仍会常常变化——尽管如此,在大部分情况下它已经能很好的工作。



我们还需要配置 wpa_supplicant本身,这将会比较麻烦一些,具体取决于你要连接的AP的安全程度。下面的例子是从 /usr/share/doc/wpa_supplicant-/wpa_supplicant.conf.gz中抽取并简化而来的,此文件出自 wpa_supplicant软件包。

代码 2.3: 一个/etc/wpa_supplicant/wpa_supplicant.conf的例子

# 请不要修改下面这一行内容,否则将不能正常工作
ctrl_interface=/var/run/wpa_supplicant

# 确保只有root用户能读取WPA的配置
ctrl_interface_group=0

# 使用wpa_supplicant来扫描和选择AP
ap_scan=1

# 简单的情形:WPA-PSk密码验证方式,PSK是ASCII密码短语,所有合法的加密方式都允许连接
network={
ssid="simple"
psk="very secret passphrase"
# 优先级越高,就能越早匹配到。
priority=5
}

# 与前面的设置相同,但要求对特定的SSID进行扫描(针对那些拒绝广播SSID的AP)
network={
ssid="second ssid"
scan_ssid=1
psk="very secret passphrase"
priority=2
}

# 仅使用WPA-PSK方式。允许使用任何合法的加密方式的组合
network={
ssid="example"
proto=WPA
key_mgmt=WPA-PSK
pairwise=CCMP TKIP
group=CCMP TKIP WEP104 WEP40
psk=06b4be19da289f475aa46a33cb793029d4ab3db7a23ee92382eb0106c72ac7bb
priority=2
}

# 明文连接方式(不使用WPA和IEEE802.1X)
network={
ssid="plaintext-test"
key_mgmt=NONE
}

# 共享WEP秘钥连接方式(不使用WPA和IEEE802.1X)
network={
ssid="static-wep-test"
key_mgmt=NONE
wep_key0="abcde"
wep_key1=0102030405
wep_key2="1234567890123"
wep_tx_keyidx=0
priority=5
}

# 共享WEP秘钥连接方式(无WPA和IEEE802.1X),使用共享秘钥IEEE802.11验证方式
network={
ssid="static-wep-test2"
key_mgmt=NONE
wep_key0="abcde"
wep_key1=0102030405
wep_key2="1234567890123"
wep_tx_keyidx=0
priority=5
auth_alg=SHARED
}

# 在IBSS/ad-hoc网络中使用WPA-None/TKIP
network={
ssid="test adhoc"
mode=1
proto=WPA
key_mgmt=WPA-NONE
pairwise=NONE
group=TKIP
psk="secret passphrase"
}

命令执行例子:
wpa_supplicant -B -ieth0 -c /etc/wpa_supplicant.conf
获得地址:
dhcpcd eth0
察看网卡状态以及参数:
bt ~ # iwconfig eth0
eth0      IEEE 802.11g  ESSID:"youssid"
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:00:00:00:00:00
          Bit Rate:54 Mb/s   Tx-Power:14 dBm
          Retry limit:15   RTS thr:off   Fragment thr:off
          Encryption key:xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx-xxxx   Security mode:open
          Power Management:off
          Link Quality=74/100  Signal level=-57 dBm  Noise level=-57 dBm
          Rx invalid nwid:0  Rx invalid crypt:1  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:21   Missed beacon:0

bt ~ # ifconfig eth0
eth0      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet addr:192.168.2.100  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::218:deff:feb0:38e5/64 Scope:Link
          UP BROADCAST NOTRAILERS RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:33 errors:2 dropped:31 overruns:0 frame:0
          TX packets:12 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:11177 (10.9 KiB)  TX bytes:4324 (4.2 KiB)
          Interrupt:11 Base address:0x2000 Memory:edf00000-edf00fff

这样linux就可以使用wpa 访问无线网络了.
---------------------------------------------------
wpa_supplicant usage
---------------------------------------------------
You will need to make a configuration file, e.g.,
/etc/wpa_supplicant.conf, with network configuration for the networks
you are going to use. Configuration file section below includes
explanation for the configuration file format and includes various
examples. Once the configuration is ready, you can test whether the
configuration work by first running wpa_supplicant with following
command to start it on foreground with debugging enabled:

wpa_supplicant -i wlan0 -c/etc/wpa_supplicant.conf -d

Assuming everything goes fine, you can start using following command
to start wpa_supplicant on background without debugging:

wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -B

Please note that if you included more than one driver interface in the
build time configuration (.config), you may need to specify which
interface to use by including -D option on the command
line. See following section for more details on command line options
for wpa_supplicant.



Command line options
--------------------

usage:
wpa_supplicant [-BddehLqqvw] -i -c [-D] \
[-N -i -c [-D] ...]

options:
-B = run daemon in the background
-d = increase debugging verbosity (-dd even more)
-K = include keys (passwords, etc.) in debug output
-t = include timestamp in debug messages
-h = show this help text
-L = show license (GPL and BSD)
-q = decrease debugging verbosity (-qq even less)
-v = show version
-w = wait for interface to be added, if needed
-N = start describing new interface

drivers:
hostap = Host AP driver (Intersil Prism2/2.5/3) [default]
(this can also be used with Linuxant DriverLoader)
hermes = Agere Systems Inc. driver (Hermes-I/Hermes-II)
madwifi = MADWIFI 802.11 support (Atheros, etc.)
atmel = ATMEL AT76C5XXx (USB, PCMCIA)
wext = Linux wireless extensions (generic)
ndiswrapper = Linux ndiswrapper
broadcom = Broadcom wl.o driver
ipw = Intel ipw2100/2200 driver
wired = wpa_supplicant wired Ethernet driver
bsd = BSD 802.11 support (Atheros, etc.)
ndis = Windows NDIS driver

In most common cases, wpa_supplicant is started with

wpa_supplicant -Bw -c/etc/wpa_supplicant.conf -iwlan0

This makes the process fork into background and wait for the wlan0
interface if it is not available at startup time.

The easiest way to debug problems, and to get debug log for bug
reports, is to start wpa_supplicant on foreground with debugging
enabled:

wpa_supplicant -c/etc/wpa_supplicant.conf -iwlan0 -d


wpa_supplicant can control multiple interfaces (radios) either by
running one process for each interface separately or by running just
one process and list of options at command line. Each interface is
separated with -N argument. As an example, following command would
start wpa_supplicant for two interfaces:

wpa_supplicant \
-c wpa1.conf -i wlan0 -D hostap -N \
-c wpa2.conf -i ath0 -D madwifi


Configuration file
------------------

wpa_supplicant is configured using a text file that lists all accepted
networks and security policies, including pre-shared keys. See
example configuration file, wpa_supplicant.conf, for detailed
information about the configuration format and supported fields.

Changes to configuration file can be reloaded be sending SIGHUP signal
to wpa_supplicant (''killall -HUP wpa_supplicant''). Similarly,
reloading can be triggered with ''wpa_cli reconfigure'' command.

Configuration file can include one or more network blocks, e.g., one
for each used SSID. wpa_supplicant will automatically select the best
betwork based on the order of network blocks in the configuration
file, network security level (WPA/WPA2 is prefered), and signal
strength.

Example configuration files for some common configurations:

1) WPA-Personal (PSK) as home network and WPA-Enterprise with EAP-TLS as work
network

# allow frontend (e.g., wpa_cli) to be used by all users in ''wheel'' group
ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
#
# home network; allow all valid ciphers
network={
ssid="home"
scan_ssid=1
key_mgmt=WPA-PSK
psk="very secret passphrase"
}
#
# work network; use EAP-TLS with WPA; allow only CCMP and TKIP ciphers
network={
ssid="work"
scan_ssid=1
key_mgmt=WPA-EAP
pairwise=CCMP TKIP
group=CCMP TKIP
eap=TLS
identity="user@example.com"
ca_cert="/etc/cert/ca.pem"
client_cert="/etc/cert/user.pem"
private_key="/etc/cert/user.prv"
private_key_passwd="password"
}


2) WPA-RADIUS/EAP-PEAP/MSCHAPv2 with RADIUS servers that use old peaplabel
(e.g., Funk Odyssey and SBR, Meetinghouse Aegis, Interlink RAD-Series)

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="example"
scan_ssid=1
key_mgmt=WPA-EAP
eap=PEAP
identity="user@example.com"
password="foobar"
ca_cert="/etc/cert/ca.pem"
phase1="peaplabel=0"
phase2="auth=MSCHAPV2"
}


3) EAP-TTLS/EAP-MD5-Challenge configuration with anonymous identity for the
unencrypted use. Real identity is sent only within an encrypted TLS tunnel.

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="example"
scan_ssid=1
key_mgmt=WPA-EAP
eap=TTLS
identity="user@example.com"
anonymous_identity="anonymous@example.com"
password="foobar"
ca_cert="/etc/cert/ca.pem"
phase2="auth=MD5"
}


4) IEEE 802.1X (i.e., no WPA) with dynamic WEP keys (require both unicast and
broadcast); use EAP-TLS for authentication

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="1x-test"
scan_ssid=1
key_mgmt=IEEE8021X
eap=TLS
identity="user@example.com"
ca_cert="/etc/cert/ca.pem"
client_cert="/etc/cert/user.pem"
private_key="/etc/cert/user.prv"
private_key_passwd="password"
eapol_flags=3
}


5) Catch all example that allows more or less all configuration modes. The
configuration options are used based on what security policy is used in the
selected SSID. This is mostly for testing and is not recommended for normal
use.

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
network={
ssid="example"
scan_ssid=1
key_mgmt=WPA-EAP WPA-PSK IEEE8021X NONE
pairwise=CCMP TKIP
group=CCMP TKIP WEP104 WEP40
psk="very secret passphrase"
eap=TTLS PEAP TLS
identity="user@example.com"
password="foobar"
ca_cert="/etc/cert/ca.pem"
client_cert="/etc/cert/user.pem"
private_key="/etc/cert/user.prv"
private_key_passwd="password"
phase1="peaplabel=0"
ca_cert2="/etc/cert/ca2.pem"
client_cert2="/etc/cer/user.pem"
private_key2="/etc/cer/user.prv"
private_key2_passwd="password"
}


6) Authentication for wired Ethernet. This can be used with ''wired'' interface
(-Dwired on command line).

ctrl_interface=/var/run/wpa_supplicant
ctrl_interface_group=wheel
ap_scan=0
network={
key_mgmt=IEEE8021X
eap=MD5
identity="user"
password="password"
eapol_flags=0
}
---------------------------------------------------
wpa_cli usage
---------------------------------------------------

wpa_cli commands

status = get current WPA/EAPOL/EAP status
mib = get MIB variables (dot1x, dot11)
help = show this usage help
interface [ifname] = show interfaces/select interface
level = change debug level
license = show full wpa_cli license
logoff = IEEE 802.1X EAPOL state machine logoff
logon = IEEE 802.1X EAPOL state machine logon
set = set variables (shows list of variables when run without arguments)
pmksa = show PMKSA cache
reassociate = force reassociation
reconfigure = force wpa_supplicant to re-read its configuration file
preauthenticate = force preauthentication
identity = configure identity for an SSID
password = configure password for an SSID
pin = configure pin for an SSID
otp = configure one-time-password for an SSID
passphrase = configure private key passphrase
for an SSID
bssid = set preferred BSSID for an SSID
list_networks = list configured networks
select_network = select a network (disable others)
enable_network = enable a network
disable_network = disable a network
add_network = add a network
remove_network = remove a network
set_network = set network variables (shows
list of variables when run without arguments)
get_network = get network variables
save_config = save the current configuration
disconnect = disconnect and wait for reassociate command before connecting
scan = request new BSS scan
scan_results = get latest scan results
get_capability = get capabilies
terminate = terminate wpa_supplicant
quit = exit wpa_cli


wpa_cli command line options

wpa_cli [-p] [-i] [-hvB] [-a] \
[-P] [-g] [command..]
-h = help (show this usage text)
-v = shown version information
-a = run in daemon mode executing the action file based on events from
wpa_supplicant
-B = run a daemon in the background
default path: /var/run/wpa_supplicant
default interface: first interface found in socket path
#include <reg52.h> #include <intrins.h> // 引脚定义 sbit LSA = P1^0; // 74HC138译码器A输入端 sbit LSB = P1^1; // 74HC138译码器B输入端 sbit LSC = P1^2; // 74HC138译码器C输入端 sbit BUZZER = P1^5; // 蜂鸣器控制引脚 // 按键定义 sbit K1 = P3^0; // 设置键 sbit K2 = P3^1; // 增加键 sbit K3 = P3^2; // 减少键 sbit K4 = P3^3; // 闹钟功能键 // 数码管段码表(共阴极) // 0-9, 减号, H-J, K-Z, 熄灭符 unsigned char code seg_table[] = { 0x3F, 0x06, 0x5B, 0x4F, 0x66, 0x6D, 0x7D, 0x07, 0x7F, 0x6F, // 数字0-9 0x40, // 减号(-) 0x76, 0x79, 0x38, 0x3F, 0x77, 0x7C, 0x39, 0x5C, 0x73, 0x3E, // 字母H(11)-J(20) 0x75, 0x37, 0x7D, 0x7A, 0x3F, 0x71, 0x00 // 字母K(21)-Z(26), 熄灭符(27) }; // "HELLO"显示码表(对应seg_table索引) unsigned char code hello[] = {11, 12, 13, 13, 0}; // H(11), E(12), L(13), L(13), O(0) // 时间变量 unsigned char hour = 23; // 小时(初始值23) unsigned char minute = 58; // 分钟(初始值58) unsigned char second = 40; // 秒(初始值40) unsigned int timer_count = 0; // 定时器计数(用于秒计时) // 闹钟变量 unsigned char alarm_hour = 0; // 闹钟小时 unsigned char alarm_minute = 0; // 闹钟分钟 unsigned char alarm_second = 0; // 闹钟秒 bit alarm_enabled = 0; // 闹钟使能标志 bit alarm_ringing = 0; // 闹钟响铃标志 unsigned int alarm_duration = 0; // 闹钟响铃持续时间计数(1000=1秒) // 模式设置变量 unsigned char setting_mode = 0; // 时间设置模式:0-正常显示,1-设置小时,2-设置分钟,3-设置秒 unsigned char alarm_setting = 0; // 闹钟设置模式:0-正常显示,1-设置闹钟小时,2-设置闹钟分钟,3-设置闹钟秒 // 闪烁控制变量 unsigned char time_flash_count = 0; // 时间设置闪烁计数 unsigned char alarm_flash_count = 0; // 闹钟设置闪烁计数 // 按键标志变量 bit setting_key_pressed = 0; // 设置键按下标志 bit increase_key_pressed = 0; // 增加键按下标志 bit decrease_key_pressed = 0; // 减少键按下标志 bit alarm_key_pressed = 0; // 闹钟键按下标志 // 按键状态变量 unsigned char key_state[4] = {0}; // 按键状态:0-释放,1-按下检测,2-确认按下,3-释放检测 unsigned char key_count[4] = {0}; // 按键消抖计数 // 延时函数(@11MHz,约1ms) void delay(unsigned int t) { unsigned int i, j; for (i = t; i > 0; i--) for (j = 113; j > 0; j--); } // 按键检测函数(带消抖处理) void check_keys() { // 检测设置键(K1) if (key_state[0] == 0 && K1 == 0) { key_state[0] = 1; key_count[0] = 0; } else if (key_state[0] == 1) { key_count[0]++; if (key_count[0] > 10) { // 超过20ms确认按下 key_state[0] = 2; setting_key_pressed = 1; } } else if (key_state[0] == 2 && K1 == 1) { key_state[0] = 3; key_count[0] = 0; } else if (key_state[0] == 3) { key_count[0]++; if (key_count[0] > 10) { key_state[0] = 0; } } // 检测增加键(K2) if (key_state[1] == 0 && K2 == 0) { key_state[1] = 1; key_count[1] = 0; } else if (key_state[1] == 1) { key_count[1]++; if (key_count[1] > 10) { key_state[1] = 2; increase_key_pressed = 1; } } else if (key_state[1] == 2 && K2 == 1) { key_state[1] = 3; key_count[1] = 0; } else if (key_state[1] == 3) { key_count[1]++; if (key_count[1] > 10) { key_state[1] = 0; } } // 检测减少键(K3) if (key_state[2] == 0 && K3 == 0) { key_state[2] = 1; key_count[2] = 0; } else if (key_state[2] == 1) { key_count[2]++; if (key_count[2] > 10) { key_state[2] = 2; decrease_key_pressed = 1; } } else if (key_state[2] == 2 && K3 == 1) { key_state[2] = 3; key_count[2] = 0; } else if (key_state[2] == 3) { key_count[2]++; if (key_count[2] > 10) { key_state[2] = 0; } } // 检测闹钟键(K4) if (key_state[3] == 0 && K4 == 0) { key_state[3] = 1; key_count[3] = 0; } else if (key_state[3] == 1) { key_count[3]++; if (key_count[3] > 10) { key_state[3] = 2; alarm_key_pressed = 1; } } else if (key_state[3] == 2 && K4 == 1) { key_state[3] = 3; key_count[3] = 0; } else if (key_state[3] == 3) { key_count[3]++; if (key_count[3] > 10) { key_state[3] = 0; } } } // 数码管单个数字显示函数 void display_digit(unsigned char pos, unsigned char num) { // 选择数码管位置(0-7) switch (pos) { case 0: LSA=0; LSB=0; LSC=0; break; // 第1位数码管 case 1: LSA=1; LSB=0; LSC=0; break; // 第2位数码管 case 2: LSA=0; LSB=1; LSC=0; break; // 第3位数码管 case 3: LSA=1; LSB=1; LSC=0; break; // 第4位数码管 case 4: LSA=0; LSB=0; LSC=1; break; // 第5位数码管 case 5: LSA=1; LSB=0; LSC=1; break; // 第6位数码管 case 6: LSA=0; LSB=1; LSC=1; break; // 第7位数码管 case 7: LSA=1; LSB=1; LSC=1; break; // 第8位数码管 } P0 = seg_table[num]; // 输出段码到数码管 delay(1); // 显示维持1ms P0 = 0x00; // 消隐,防止重影 } // 时间显示函数(--) void display_time() { // 闪烁控制计数(用于设置模式下的数字闪烁) time_flash_count++; // 显示小时 if (setting_mode == 1 && time_flash_count < 20) { // 设置小时模式,数字闪烁 display_digit(0, 27); // 显示熄灭符 display_digit(1, 27); // 显示熄灭符 } else { display_digit(0, hour / 10); // 小时十位 display_digit(1, hour % 10); // 小时个位 } display_digit(2, 10); // 显示分隔符(-) // 显示分钟 if (setting_mode == 2 && time_flash_count < 20) { // 设置分钟模式,数字闪烁 display_digit(3, 27); // 显示熄灭符 display_digit(4, 27); // 显示熄灭符 } else { display_digit(3, minute / 10); // 分钟十位 display_digit(4, minute % 10); // 分钟个位 } display_digit(5, 10); // 显示分隔符(-) // 显示秒 if (setting_mode == 3 && time_flash_count < 20) { // 设置秒模式,数字闪烁 display_digit(6, 27); // 显示熄灭符 display_digit(7, 27); // 显示熄灭符 } else { display_digit(6, second / 10); // 秒十位 display_digit(7, second % 10); // 秒个位 } if (time_flash_count >= 40) time_flash_count = 0; // 重置闪烁计数 } // 闹钟显示函数(--) void display_alarm() { alarm_flash_count++; // 显示闹钟小时 if (alarm_setting == 1 && alarm_flash_count < 20) { // 设置闹钟小时模式,数字闪烁 display_digit(0, 27); // 显示熄灭符 display_digit(1, 27); // 显示熄灭符 } else { display_digit(0, alarm_hour / 10); // 闹钟小时十位 display_digit(1, alarm_hour % 10); // 闹钟小时个位 } display_digit(2, 10); // 显示分隔符(-) // 显示闹钟分钟 if (alarm_setting == 2 && alarm_flash_count < 20) { // 设置闹钟分钟模式,数字闪烁 display_digit(3, 27); // 显示熄灭符 display_digit(4, 27); // 显示熄灭符 } else { display_digit(3, alarm_minute / 10); // 闹钟分钟十位 display_digit(4, alarm_minute % 10); // 闹钟分钟个位 } display_digit(5, 10); // 显示分隔符(-) // 显示闹钟秒 if (alarm_setting == 3 && alarm_flash_count < 20) { // 设置闹钟秒模式,数字闪烁 display_digit(6, 27); // 显示熄灭符 display_digit(7, 27); // 显示熄灭符 } else { display_digit(6, alarm_second / 10); // 闹钟秒十位 display_digit(7, alarm_second % 10); // 闹钟秒个位 } if (alarm_flash_count >= 40) alarm_flash_count = 0; // 重置闪烁计数 } // 开机欢迎界面:显示"HELLO"(滚动效果) void display_hello() { unsigned char i; unsigned char loop; // 循环计数器(控制显示时长) // 显示参数定义 const unsigned char SCAN_DELAY = 1; // 扫描延时(1ms,保证显示稳定) const unsigned char LOOP_COUNT = 20; // 循环次数(控制显示时长) for (loop = 0; loop < LOOP_COUNT; loop++) { // 循环显示20次 for (i = 0; i < 5; i++) { // 显示5个字符H-E-L-L-O // 选择数码管位置(对应0-4位数码管) switch (i) { case 0: LSA=0; LSB=0; LSC=0; break; // 第1位 case 1: LSA=1; LSB=0; LSC=0; break; // 第2位 case 2: LSA=0; LSB=1; LSC=0; break; // 第3位 case 3: LSA=1; LSB=1; LSC=0; break; // 第4位 case 4: LSA=0; LSB=0; LSC=1; break; // 第5位 } // 输出字符段码 P0 = seg_table[hello[i]]; // 显示对应字符 delay(2); // 维持2ms // 注意:数码管动态扫描,需要循环刷新所有位 } } // 显示完成后关闭所有数码管(消隐) P0 = 0x00; } // 开机LED流动效果(用于系统初始化检测) void startup_led_flow() { unsigned char i; // 从左到右点亮LED for (i = 0; i < 8; i++) { P2 = ~(1 << i); // 逐位点亮LED delay(150); // 延时150ms } // 从右到左点亮LED for (i = 0; i < 8; i++) { P2 = ~(1 << (7 - i)); // 反向逐位点亮LED delay(150); // 延时150ms } // 闪烁三次 for (i = 0; i < 3; i++) { P2 = 0x00; // 全部点亮 delay(300); // 延时300ms P2 = 0xFF; // 全部熄灭 delay(300); // 延时300ms } P2 = 0xFF; // 最终全部熄灭 } // 数码管测试函数(检测8个数码管是否正常) void seg_test() { unsigned char i, j; for (j = 0; j < 2; j++) { for (i = 0; i < 8; i++) { // 选择数码管位置 switch (i) { case 0: LSA=0; LSB=0; LSC=0; break; case 1: LSA=1; LSB=0; LSC=0; break; case 2: LSA=0; LSB=1; LSC=0; break; case 3: LSA=1; LSB=1; LSC=0; break; case 4: LSA=0; LSB=0; LSC=1; break; case 5: LSA=1; LSB=0; LSC=1; break; case 6: LSA=0; LSB=1; LSC=1; break; case 7: LSA=1; LSB=1; LSC=1; break; } P0 = 0x7F; // 显示全亮(测试所有段) delay(200); // 延时200ms } P0 = 0x00; // 消隐 delay(300); // 延时300ms } } // 定时器0初始化(1ms中断) void timer0_init() { TMOD |= 0x01; // 设置定时器0为模式1(16位定时器) TH0 = 0xFC; // 设置定时器初值高8位(定时1ms) TL0 = 0x66; // 设置定时器初值低8位 ET0 = 1; // 使能定时器0中断 EA = 1; // 开总中断 TR0 = 1; // 启动定时器0 } // 定时器0中断服务函数 void timer0_isr() interrupt 1 { TH0 = 0xFC; // 重新加载定时器初值 TL0 = 0x66; timer_count++; if (timer_count >= 1000) { // 计数到1000次,即1秒 timer_count = 0; second++; if (second >= 60) { // 秒满60,分钟加1 second = 0; minute++; if (minute >= 60) { // 分钟满60,小时加1 minute = 0; hour++; if (hour >= 24) { // 小时满24,重置为0 hour = 0; } } } // 检查闹钟是否触发 if (alarm_enabled && hour == alarm_hour && minute == alarm_minute && second == alarm_second) { alarm_ringing = 1; // 触发闹钟 alarm_duration = 0; // 重置闹钟持续时间计数 } } // 控制闹钟响铃时间 if (alarm_ringing) { alarm_duration++; if (alarm_duration >= 10000) { // 响铃10秒后停止 alarm_ringing = 0; } } } // 主函数 void main() { unsigned char i; // 初始化I/O口 P2 = 0xFF; // P2口输出高电平(关闭所有LED) P0 = 0x00; // P0口输出低电平(关闭所有数码管) BUZZER = 1; // 关闭蜂鸣器(高电平触发) // 开机动画 for (i = 0; i < 1; i++) { startup_led_flow(); // LED流动效果 } // 数码管测试 seg_test(); // 显示欢迎信息"HELLO" for (i = 0; i < 10; i++) { display_hello(); delay(1); } // 初始化定时器0 timer0_init(); // 主循环 while (1) { // 检测按键 check_keys(); // 处理设置键 if (setting_key_pressed) { setting_key_pressed = 0; if (alarm_setting == 0) { // 如果不在闹钟设置模式 setting_mode = (setting_mode + 1) % 4; // 循环切换时间设置模式(0-3) } else { alarm_setting = (alarm_setting + 1) % 4; // 循环切换闹钟设置模式(0-3) } } // 处理闹钟键 if (alarm_key_pressed) { alarm_key_pressed = 0; alarm_setting = (alarm_setting + 1) % 4; // 循环切换闹钟设置模式(0-3) if (alarm_setting == 0) { // 如果退出闹钟设置模式 alarm_enabled = 1; // 启用闹钟 } } // 处理增加键 if (increase_key_pressed) { increase_key_pressed = 0; if (setting_mode == 1) hour = (hour + 1) % 24; // 增加小时 else if (setting_mode == 2) minute = (minute + 1) % 60; // 增加分钟 else if (setting_mode == 3) second = (second + 1) % 60; // 增加秒 else if (alarm_setting == 1) alarm_hour = (alarm_hour + 1) % 24; // 增加闹钟小时 else if (alarm_setting == 2) alarm_minute = (alarm_minute + 1) % 60; // 增加闹钟分钟 else if (alarm_setting == 3) alarm_second = (alarm_second + 1) % 60; // 增加闹钟秒 } // 处理减少键 if (decrease_key_pressed) { decrease_key_pressed = 0; if (setting_mode == 1) hour = (hour + 23) % 24; // 减少小时 else if (setting_mode == 2) minute = (minute + 59) % 60; // 减少分钟 else if (setting_mode == 3) second = (second + 59) % 60; // 减少秒 else if (alarm_setting == 1) alarm_hour = (alarm_hour + 23) % 24; // 减少闹钟小时 else if (alarm_setting == 2) alarm_minute = (alarm_minute + 59) % 60; // 减少闹钟分钟 else if (alarm_setting == 3) alarm_second = (alarm_second + 59) % 60; // 减少闹钟秒 } // 控制蜂鸣器 if (alarm_ringing) { // 蜂鸣器响铃(发出约500Hz的声音) for(i=0; i<50; i++) { BUZZER = 1; // 蜂鸣器开 delay(1); // 延时1ms BUZZER = 0; // 蜂鸣器关 delay(1); // 延时1ms } } else { BUZZER = 0; // 关闭蜂鸣器 } // 显示时间或闹钟设置 if (alarm_setting == 0) { display_time(); // 显示当前时间 } else { display_alarm(); // 显示闹钟设置 } } }在这代码的基础上,写一个简单的代码,实现串口(从单片机发时钟内容给电脑串口显示)(电脑串口发命令给单片机执行)
最新发布
05-29
<think>嗯,用户想在现有的单片机代码里添加串口通信功能,实现双向的数据传输。首先我得确定他用的单片机型号,但用户没提到,可能需要假设常见的比如51或者STM32。不过根据引用里的内容,提到了MAX232和CH340,可能用的是51单片机,因为这类芯片常用于RS232转换。接下来,用户需要发送时钟数据到电脑,并接收命令。首先硬件连接部分,用户可能已经通过USB转串口模块连接了单片机,比如使用CH340芯片。需要确保单片机的串口引脚(如TXD和RXD)正确连接到转换芯片,然后再连接到电脑的USB口。 然后是软件部分,需要配置单片机的串口模块。这包括设置波特率、数据位、停止位、校验位等参数,确保与电脑端的串口助手设置一致。比如常用的9600波特率,8数据位,1停止位,无校验。对于51单片机,可能需要配置定时器来生成波特率,启用串口中断,以便在接收到数据时触发中断服务程序。在代码层面,初始化串口后,需要编写发送函数,将时钟数据格式化为字符串,通过串口发送。比如,时钟数据可能是时分秒,需要转换成ASCII码,然后逐个发送。同时,接收部分需要处理电脑发送的命令,可能需要在中断服务程序中读取接收到的字符,并存储到缓冲区,直到检测到结束符(如回车换行),再进行解析和执行对应的操作。还需要考虑数据格式的问题,比如电脑端发送的命令可能是文本格式,如“SET12:34:56”,单片机需要解析这个字符串,提取出时间参数并设置内部时钟。同时,发送数据时可能需要定时发送,比如每秒发送一次当前时间,或者由电脑发送请求命令来触发单片机发送数据。 此外,代码的整合需要考虑现有代码的结构,确保串口功能的添加不会影响原有的时钟功能。可能需要使用中断来保证实时性,避免因为发送数据而阻塞主程序运行。同时,要注意缓冲区的大小,防止数据溢出。可能遇到的问题包括波特率不匹配导致乱码,或者中断配置错误导致无法接收数据。还有电平转换的问题,如果用的是TTL电平,需要确保CH340正确转换到USB信号。另外,数据解析时需要考虑错误处理,比如接收到无效命令时的应对措施。最后,测试阶段需要用串口调试助手验证发送和接收功能,发送测试命令查看单片机是否执行,并检查发送的时钟数据是否正确显示。可能需要逐步调试,先确保发送功能正常,再测试接收部分。</think>在现有单片机代码中添加串口通信功能需要分硬件连接和软件编程两个层面实现。以下是具体实现步骤: ### 一、硬件连接配置 1. **电平转换电路**: - 若使用USB转TTL串口线(如CH340芯片),直接连接单片机的`TXD`(发送)和`RXD`(接收)引脚到转换芯片的对应端口[^1] - 若使用RS232通信,需通过MAX232芯片完成TTL与RS232电平转换[^1] 2. **物理接线**: - 单片机`TXD` -> 转换芯片`RXD` - 单片机`RXD` -> 转换芯片`TXD` - 共地连接(GND) ### 二、软件实现步骤 #### (一)串口初始化配置 ```c // 以51单片机为例 void UART_Init() { SCON = 0x50; // 模式1,允许接收 TMOD |= 0x20; // 定时器1模式2 TH1 = 0xFD; // 9600波特率@11.0592MHz TL1 = TH1; TR1 = 1; // 启动定时器1 ES = 1; // 允许串口中断 EA = 1; // 全局中断使能 } ``` #### (二)时钟数据发送实现 ```c // 发送字符串函数 void UART_SendString(char *str) { while(*str) { SBUF = *str++; while(!TI); TI = 0; } } // 示例:发送时分秒数据 void Send_Time(uint8_t hour, uint8_t min, uint8_t sec) { char buffer[20]; sprintf(buffer, "Time: %02d:%02d:%02d\r\n", hour, min, sec); UART_SendString(buffer); } ``` #### (三)命令接收处理 ```c // 中断服务程序 void UART_ISR() interrupt 4 { if(RI) { static char cmd_buffer[32]; static uint8_t index = 0; cmd_buffer[index++] = SBUF; if(cmd_buffer[index-1] == '\r' || index >= 31) { // 检测结束符 cmd_buffer[index-1] = '\0'; Parse_Command(cmd_buffer); // 命令解析函数 index = 0; } RI = 0; } } // 命令解析示例 void Parse_Command(char *cmd) { if(strncmp(cmd, "SET", 3) == 0) { // 解析设置时间命令 SET 12:34:56 sscanf(cmd+4, "%d:%d:%d", &hour, &min, &sec); } } ``` ### 三、系统整合要点 1. **定时发送机制**: - 使用定时器每秒发送一次时钟数据 - 或通过接收特定指令触发发送(如`GET_TIME`) 2. **数据协议设计**: - 定义标准数据格式:`HH:MM:SS\r\n` - 命令格式:`<CMD> <PARAM>\r\n` 3. **错误处理**: - 添加数据校验位 - 设置接收超时机制 ### 四、调试建议 1. 使用串口调试助手验证数据收发 2. 先测试单字节收发,再逐步实现完整协议 3. 注意波特率误差(推荐使用11.0592MHz晶振)
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