Mbed OS 文档翻译 之 参考（API（网络接口（Cellular）））
Cellular
CellularBase 类层次结构
CellularBase 提供了一个 C++ API，用于通过蜂窝设备连接到互联网。
Arm Mbed OS 提供了 CellularBase 的参考实现，它具有更多信息。
Cellular
CellularBase 提供了一个 C++ API，用于通过蜂窝设备连接到互联网。
Arm Mbed OS 提供了 CellularBase 的参考实现。
入门
-
选择支持蜂窝的 Mbed 板，例如 UBLOX-C027 或 MTS-DRAGONFLY。
-
克隆
mbed-os-example-cellular。按照存储库中的说明进行操作。- 编译代码。
- 下载到板子。
您会看到类似于以下摘录的输出：
mbed-os-example-cellular
Establishing connection ......
Connection Established.
TCP: connected with echo.mbedcloudtesting.com server
TCP: Sent 4 Bytes to echo.mbedcloudtesting.com
Received from echo server 4 Bytes
Success. Exiting
基本工作原则
您可以通过各种不同方式使用和扩展蜂窝接口。例如，
- 使用 AT 命令控制蜂窝调制解调器内置的现有 IP 栈中的套接字。
- 使用 PPP（点对点协议）管道在 Mbed OS 支持的 IP 栈和蜂窝调制解调器设备之间传递 IP 数据包。
mbed-os-example-cellular 使用简单的蜂窝连接。它取决于调制解调器应用程序是使用 PPP 还是 AT 模式。我们可以总结这个特定的设计如下：
- 它使用外部 IP 栈（如 LWIP）或片上网络栈（例如调制解调器不支持 PPP 时）。
- 简单的蜂窝连接使用标准的 3GPP AT 27.007 AT 命令来建立蜂窝调制解调器并注册到网络。
- 注册后，驱动程序使用带有蜂窝调制解调器的 LWIP 打开 PPP 管道并连接到互联网。如果正在使用仅 AT 模式，则调制解调器专用的 AT 命令用于套接字数据控制。
CellularBase 类参考
CellularBase 类参考
| 公共成员函数 | |
| virtual void | set_credentials (const char *apn, const char *uname=0, const char *pwd=0)=0 |
| virtual void | set_sim_pin (const char *sim_pin)=0 |
| virtual nsapi_error_t | connect (const char *sim_pin, const char *apn=0, const char *uname=0, const char *pwd=0)=0 |
| virtual nsapi_error_t | connect ()=0 |
| virtual nsapi_error_t | disconnect ()=0 |
| virtual bool | is_connected ()=0 |
| virtual const char * | get_ip_address ()=0 |
| virtual const char * | get_netmask ()=0 |
| virtual const char * | get_gateway ()=0 |
| virtual CellularBase * | cellularBase () |
| 公共成员函数继承自 NetworkInterface | |
| virtual const char * | get_mac_address () |
| virtual nsapi_error_t | set_network (const char *ip_address, const char *netmask, const char *gateway) |
| virtual nsapi_error_t | set_dhcp (bool dhcp) |
| virtual nsapi_error_t | gethostbyname (const char *host, SocketAddress *address, nsapi_version_t version=NSAPI_UNSPEC) |
| virtual nsapi_value_or_error_t | gethostbyname_async (const char *host, hostbyname_cb_t callback, nsapi_version_t version=NSAPI_UNSPEC) |
| virtual nsapi_error_t | gethostbyname_async_cancel (int id) |
| virtual nsapi_error_t | add_dns_server (const SocketAddress &address) |
| virtual void | attach (mbed::Callback< void(nsapi_event_t, intptr_t)> status_cb) |
| virtual nsapi_connection_status_t | get_connection_status () const |
| virtual nsapi_error_t | set_blocking (bool blocking) |
| virtual EthInterface * | ethInterface () |
| virtual WiFiInterface * | wifiInterface () |
| virtual MeshInterface * | meshInterface () |
| virtual EMACInterface * | emacInterface () |
| 静态公共成员函数 | |
| static CellularBase * | get_default_instance () |
| 静态公共成员函数继承自 NetworkInterface | |
| static NetworkInterface * | get_default_instance () |
| 静态保护的成员函数 | |
| static CellularBase * | get_target_default_instance () |
| 静态保护的成员函数继承自 NetworkInterface | |
| static NetworkInterface * | get_target_default_instance () |
| 其他继承成员 | |
| 继承自的公共类型 NetworkInterface | |
| typedef mbed::Callback< void(nsapi_error_t result, SocketAddress *address)> | hostbyname_cb_t |
| 继承自的公共类型 DNS | |
| typedef mbed::Callback< void(nsapi_error_t result, SocketAddress *address)> | hostbyname_cb_t |
| 受保护的成员函数继承自 NetworkInterface | |
| virtual NetworkStack * | get_stack ()=0 |
用法
调出网络接口：
- 实例化 CellularBase 类的实现。
- 使用您的 SIM 卡的 PIN 码和网络的 APN 呼叫连接（pincode，apn）功能。
- 连接后，您可以像往常一样使用 Mbed OS 网络套接字。
Cellular 示例：连接建立
此示例使用 Mbed OS CellularInterface 建立与蜂窝网络的连接。
main.cpp 导入到 Mbed IDE
/*
* Copyright (c) 2017 ARM Limited. All rights reserved.
* SPDX-License-Identifier: Apache-2.0
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mbed.h"
#include "common_functions.h"
#include "UDPSocket.h"
#include "OnboardCellularInterface.h"
#define UDP 0
#define TCP 1
// SIM pin code goes here
#ifndef MBED_CONF_APP_SIM_PIN_CODE
# define MBED_CONF_APP_SIM_PIN_CODE "1234"
#endif
#ifndef MBED_CONF_APP_APN
# define MBED_CONF_APP_APN "internet"
#endif
#ifndef MBED_CONF_APP_USERNAME
# define MBED_CONF_APP_USERNAME NULL
#endif
#ifndef MBED_CONF_APP_PASSWORD
# define MBED_CONF_APP_PASSWORD NULL
#endif
// Number of retries /
#define RETRY_COUNT 3
// CellularInterface object
OnboardCellularInterface iface;
// Echo server hostname
const char *host_name = "echo.mbedcloudtesting.com";
// Echo server port (same for TCP and UDP)
const int port = 7;
Mutex PrintMutex;
Thread dot_thread(osPriorityNormal, 512);
#define PRINT_TEXT_LENGTH 128
char print_text[PRINT_TEXT_LENGTH];
void print_function(const char *input_string)
{
PrintMutex.lock();
printf("%s", input_string);
fflush(NULL);
PrintMutex.unlock();
}
void dot_event()
{
while (true) {
wait(4);
if (!iface.is_connected()) {
print_function(".");
} else {
break;
}
}
}
/**
* Connects to the Cellular Network
*/
nsapi_error_t do_connect()
{
nsapi_error_t retcode;
uint8_t retry_counter = 0;
while (!iface.is_connected()) {
retcode = iface.connect();
if (retcode == NSAPI_ERROR_AUTH_FAILURE) {
print_function("\n\nAuthentication Failure. Exiting application\n");
return retcode;
} else if (retcode != NSAPI_ERROR_OK) {
snprintf(print_text, PRINT_TEXT_LENGTH, "\n\nCouldn't connect: %d, will retry\n", retcode);
print_function(print_text);
retry_counter++;
continue;
} else if (retcode != NSAPI_ERROR_OK && retry_counter > RETRY_COUNT) {
snprintf(print_text, PRINT_TEXT_LENGTH, "\n\nFatal connection failure: %d\n", retcode);
print_function(print_text);
return retcode;
}
break;
}
print_function("\n\nConnection Established.\n");
return NSAPI_ERROR_OK;
}
/**
* Opens a UDP or a TCP socket with the given echo server and performs an echo
* transaction retrieving current.
*/
nsapi_error_t test_send_recv()
{
nsapi_size_or_error_t retcode;
#if MBED_CONF_APP_SOCK_TYPE == TCP
TCPSocket sock;
#else
UDPSocket sock;
#endif
retcode = sock.open(&iface);
if (retcode != NSAPI_ERROR_OK) {
snprintf(print_text, PRINT_TEXT_LENGTH, "UDPSocket.open() fails, code: %d\n", retcode);
print_function(print_text);
return -1;
}
SocketAddress sock_addr;
retcode = iface.gethostbyname(host_name, &sock_addr);
if (retcode != NSAPI_ERROR_OK) {
snprintf(print_text, PRINT_TEXT_LENGTH, "Couldn't resolve remote host: %s, code: %d\n", host_name,
retcode);
print_function(print_text);
return -1;
}
sock_addr.set_port(port);
sock.set_timeout(15000);
int n = 0;
const char *echo_string = "TEST";
char recv_buf[4];
#if MBED_CONF_APP_SOCK_TYPE == TCP
retcode = sock.connect(sock_addr);
if (retcode < 0) {
snprintf(print_text, PRINT_TEXT_LENGTH, "TCPSocket.connect() fails, code: %d\n", retcode);
print_function(print_text);
return -1;
} else {
snprintf(print_text, PRINT_TEXT_LENGTH, "TCP: connected with %s server\n", host_name);
print_function(print_text);
}
retcode = sock.send((void*) echo_string, sizeof(echo_string));
if (retcode < 0) {
snprintf(print_text, PRINT_TEXT_LENGTH, "TCPSocket.send() fails, code: %d\n", retcode);
print_function(print_text);
return -1;
} else {
snprintf(print_text, PRINT_TEXT_LENGTH, "TCP: Sent %d Bytes to %s\n", retcode, host_name);
print_function(print_text);
}
n = sock.recv((void*) recv_buf, sizeof(recv_buf));
#else
retcode = sock.sendto(sock_addr, (void*) echo_string, sizeof(echo_string));
if (retcode < 0) {
snprintf(print_text, PRINT_TEXT_LENGTH, "UDPSocket.sendto() fails, code: %d\n", retcode);
print_function(print_text);
return -1;
} else {
snprintf(print_text, PRINT_TEXT_LENGTH, "UDP: Sent %d Bytes to %s\n", retcode, host_name);
print_function(print_text);
}
n = sock.recvfrom(&sock_addr, (void*) recv_buf, sizeof(recv_buf));
#endif
sock.close();
if (n > 0) {
snprintf(print_text, PRINT_TEXT_LENGTH, "Received from echo server %d Bytes\n", n);
print_function(print_text);
return 0;
}
return -1;
}
int main()
{
iface.modem_debug_on(MBED_CONF_APP_MODEM_TRACE);
/* Set Pin code for SIM card */
iface.set_sim_pin(MBED_CONF_APP_SIM_PIN_CODE);
/* Set network credentials here, e.g., APN*/
iface.set_credentials(MBED_CONF_APP_APN, MBED_CONF_APP_USERNAME, MBED_CONF_APP_PASSWORD);
print_function("\n\nmbed-os-example-cellular\n");
print_function("Establishing connection ");
dot_thread.start(dot_event);
/* Attempt to connect to a cellular network */
if (do_connect() == NSAPI_ERROR_OK) {
nsapi_error_t retcode = test_send_recv();
if (retcode == NSAPI_ERROR_OK) {
print_function("\n\nSuccess. Exiting \n\n");
return 0;
}
}
print_function("\n\nFailure. Exiting \n\n");
return -1;
}
// EOF
相关内容
- 网络套接字 API 参考概述。
- Cellular 架构。