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Network Component
Version 7.4.0
MDK Middleware for IPv4 and IPv6 Networking
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The steps to create a microcontroller application that uses TCP/IP communication are:
Only a few steps are necessary to complete the RTE Component selection:
The Network Device Driver and the Network Controller of the microcontroller need to be correctly configured. This means:
For Ethernet network communication, usually an external Ethernet PHY is required to interface the physical line to the digital MAC of the microcontroller device. The MAC usually contains two buses:
SMI is used to access the PHY’s internal registers to read the state of the link (up/down), duplex mode, speed, and to restart auto-negotiation etc. SMI is a serial bus, which allows to connect up to 32 devices. Devices on the bus are accessed using a 5-bit device address. A default device address is hardware configurable by pin-strapping on the device (some pins are sampled when a reset is asserted or at power-up).
The device’s internal weak pull-up or pull-down resistors define a default device address. This address can be changed by connecting strong pull-up or pull-down resistors externally. In this case, the ETH_PHY_ADDR
in the PHY driver needs to be changed accordingly to be able to control the PHY and to communicate with it. Use the Options for Component dialog to override the default setting for ETH_PHY_ADDR:
All configuration files for the Network Component are listed in the Project window below the Component Class Network.
The Network Core configuration file Net_Config.c contains the setting for the Local Host Name. This is a name under which the network device can be accessed on a local area network (LAN). This requires a NetBIOS Name Service to be enabled in the configuration. This name is very useful if you don't know the IP address that has been assigned to your device by the DHCP server.
The Memory Pool Size specifies the amount of RAM in bytes allocated for the memory pool. The buffers for the network packets are allocated from this memory pool. Usually, the default value of 12000 bytes is sufficient.
Many Network Services are started by the Network Core automatically. If you disable Start System Service, you need to enable/start them at runtime using the dedicated functions for that.
To change the default OS resource settings for the Network Core, use Core Thread Stack Size. The default value is 1024 bytes.
The Network Interface configuration files Net_Config_Interface_n.h contain general IP address and other settings. You also need to specify the hardware driver number that is to be used with the network interface. In case of Ethernet for example, this is usually 0. If you are using a SLIP or PPP over a serial connection, you need to specify the hardware driver number of the exact UART you wish to use. All settings for the different interfaces are described here:
Usually, the needs of most applications are served by using the default settings for the sockets. Of course, there are configuration files for all three socket types that are specified in
The configuration files for all the Network Services are explained in the respective section:
The mbed TLS component provides an API for secure communication. When selecting this software component, the mbedTLS_config.h configuration file is added to the project. The proper usage of this file is out of the scope of this document. For further information, check the online documentation of mbed TLS.
For proper operation, the Network Component requires some system configuration settings. The requirements are:
Stack_Size
).netCore_Thread
and netETH_Thread
when Ethernet Interface is enabled. So you need to increase the Number of concurrent running threads by 2. The default thread stack size should be at least 512 Bytes. Also, User Timers need to be enabled.All these changes must be done in the RTX_Conf_CM.c file. For more information, check the Network Component's Resource Requirements section.
User code template files provide access to all functions that are required to communicate over the Network. The available functions are explained in the Reference section of the Network Component. These routines can be adapted to the needs of the microcontroller application, in case more functionality is needed.
The following templates are available for the Network component:
Template Name | User Functions |
---|---|
DNS_Client.c | dns_cbfunc (Callback function for notification about DNS client events), resolve_host (DNS resolving process) |
FTP_Client_UIF.c | netFTPc_Process (Request parameters for FTP client session), netFTPc_Notify (Notify the user application when FTP client operation ends) |
FTP_Server_Access.c | netFTPs_AcceptClient (Accept or deny connection from remote FTP client) |
FTP_Server_Event.c | netFTPs_Notify (Notify the user application about events in FTP server service) |
FTP_Server_Multiuser.c | netFTPs_CheckUsername (Check if an user account exists), netFTPs_CheckPassword (Check user account password), netFTPs_FileAccess (Check if remote user is allowed to access a file) |
HTTP_Server_Access.c | netHTTPs_AcceptClient (Accept or deny connection from remote HTTP client) |
HTTP_Server_CGI.c | netCGI_ProcessQuery (Process query string received by GET request), netCGI_ProcessData (Process data received by POST request), netCGI_Script (Generate dynamic web data from a script line) |
HTTP_Server_Error.c | net_http_error (Define user-friendly HTTP error messages) |
HTTP_Server_Multiuser.c | netHTTPs_CheckAccount (Check if an user account exists), netHTTPs_FileAccess (Check if remote user is allowed to access a file) |
SMTP_Client_UIF.c | netSMTPc_Process (Request parameters for SMTP client session), netSMTPc_Notify (Notify the user application when SMTP client operation ends), netSMTPc_AcceptAuthentication (Accept or deny authentication requested by SMTP server) |
SNMP_Agent_MIB.c | mib_table (Defines MIB information data table), register_mib_table (Registers a MIB table in SNMP agent) |
TCP_Socket_Client.c | tcp_cb_client (Notify the user application about TCP socket events), send_data (Connect to TCP server and send data) |
TCP_Socket_Server.c | tcp_cb_server (Notify the user application about TCP socket events) |
Telnet_Server_Access.c | netTELNETs_AcceptClient (Accept or deny connection from remote Telnet client) |
Telnet_Server_Multiuser.c | netTELNETs_CheckUsername (Check if an user account exists), netTELNETs_CheckPassword (Check user account password) |
Telnet_Server_UIF.c | netTELNETs_ProcessMessage (Request message for Telnet server session), netTELNETs_ProcessCommand (Process a command and generate response) |
TFTP_Client_UIF.c | tftp_client_notify (Notify the user application when TFTP client operation ends) |
TFTP_Server_Access.c | netTFTPs_AcceptClient (Accept or deny connection from remote TFTP client) |
UDP_Socket.c | udp_cb_func (Notify the user application about UDP socket events), send_udp_data (Send UDP data to destination client) |
In the Manage Run-Time Environment window, the Network Core can be configured for different variants:
To enable debugging with the Network Component, simply choose the IPv4/IPv6 Debug variant in the Manage Run-Time Environment window:
All necessary files, such as the Net_Debug.c file and the debug library will be automatically added to your project.
The system is made up of several modules that output debug messages. It is possible to configure the debug output for each module separately. This can be done in the Net_Debug.c file. There are three debug levels available:
Level | Description |
---|---|
Off | The debug messages for the selected module are disabled. |
Errors Only | Only error messages are output. This mode is useful for error tracking. |
Full Debug | In this mode, all debug messages are output. |
The following debug options are available:
The owner module of the displayed debug message is identified by the message prefix. The following system and application modules are configurable for debugging:
ID | Module | Description |
---|---|---|
MEM | Memory Management Debug | Allocates and releases frame buffers. |
ETH | Ethernet Debug | Handles Ethernet link. |
PPP | PPP Debug | Handles serial line direct or modem connection PPP link. |
SLIP | SLIP Debug | Handles serial line direct or modem connection SLIP link. |
LOOP | Loopback Debug | Handles localhost loopback interface. |
ARP | ARP Debug | Handles Ethernet MAC address resolution and caching. |
IP4 | IPv4 Debug | Processes the IP version 4 network layer. |
ICMP | ICMP Debug | Processes ICMP messages. Best known example is the ping. |
IGMP | IGMP Debug | Processes IGMP messages, Hosts groups and IP Multicasting. |
IP6 | IPv6 Debug | Processes the IP version 6 network layer. |
ICMP6 | ICMPv6 Debug | Processes ICMP version 6 messages. Best known example is the ping. |
NDP6 | NDP Debug | Handles Neighbor Discovery MAC address resolution and caching. |
UDP | UDP Debug | Processes UDP frames. |
TCP | TCP Debug | Processes TCP frames. |
BSD | BSD Debug | Processes TCP and UDP frames via standard BSD Sockets API. |
NBNS | NBNS Debug | The NetBIOS Name Service maintains name access to your hardware. |
DHCP | DHCP Debug | Handles automatic configuration of IP address, Net mask, Default Gateway, and Primary and Secondary DNS servers. |
DHCP6 | DHCP6 Debug | Handles automatic configuration of IP address in IP version 6. |
DNS | DNS Debug | Handles the resolution of the IP address from a host name. |
SNMP | SNMP Debug | Manages devices on IP network. |
HTTP | HTTP Server Debug | Delivers web pages on the request to web clients. |
FTP | FTP Server Debug | Manages the files stored on the server and serves the file requests received from the clients. |
FTPC | FTP Client Debug | Connects to FTP server to transfer files on the server, and to manage files stored on the server. |
TELN | Telnet Server Debug | Allows remote clients to control the system using the command line interface. |
TFTP | TFTP Server Debug | A simple service which allows you to send files to or read files from the server. |
TFTPC | TFTP Client Debug | Connects to TFTP server to send or receive files. |
SMTP | SMTP Client Debug | Connects to SMTP server to send emails. |
SNTP | SNTP Debug | Manages clock synchronization over the network. |
An example of the debug output is:
In the above example, Ethernet, IP and TCP debug messages are enabled:
Debug messages are output to a standard IO port. The sendchar function outputs a single character. If required, you can customize this function to send the debug messages to some other device. In most cases, a serial ITM debug channel is used to print out the debug messages.
It is often necessary to change the parameters and mode of operation of the network interface at startup or runtime. System control functions allow reading and changing the settings of the network interface and the system (for example the hostname).
This is required for using the same application code for serial production of embedded devices. The runtime configuration feature enables reading of configuration parameters from an EEPROM or SD Card and configuring the network interface for each embedded device differently.
To control the network interface options, you can use:
The options which can be changed are defined in the netIF_Option enumerator. However, some interfaces do not support the complete set of available options. For example, the PPP interface does not have a MAC address. If you try to modify an unsupported option, an error is returned.
The localhost name is used to access the embedded system without knowledge of its IP address. netSYS_GetHostName is used to retrieve the localhost name, whereas netSYS_SetHostName changes the localhost name.
The DHCP client can be disabled or enabled at runtime. When disabled, the user provided network parameters defined in the Net_Config_ETH_0.h configuration file are used. Switch the state of the DHCP client using netDHCP_Disable and netDHCP_Enable.
Code Example