MDK-ARM Keil, MDK-ARM Datasheet - Page 102

• Manufacturer Part Number: MDK-ARM
• Description: KIT REALVIEW MCU DEVELOPMENT
• Manufacturer: Keil
• Type: Compiler and IDEr

Specifications of MDK-ARM

• For Use With/related Products: ARM MCUs
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

102
numeric IP address. Each record is 12 bytes in size. Once the DNS client has
been configured, we can resolve a symbolic address by calling the
get_host_by_name() function.
get_host_by_name ("www.keil.com", dns_cbfunc);
This function takes the host symbolic name as a string and also the address of a
user-defined call back function. Once invoked, the DNS client will attempt to
resolve the address by contacting the DNS server. The results will be passed to
the call back function.
static void dns_cbfunc (unsigned char event, unsigned char *ip)
}
Exercise: DNS Resolver
This exercise takes symbolic host addresses entered via a web page and resolves
the IP addresses.
Socket Library
The RL-TCPnet supports the internet applications, which are most useful to a
small, embedded system. However, you may wish to use the microcontroller’s
Ethernet peripheral for a custom application. For example, you may wish to use
the Ethernet peripheral for high-speed board-to-board communication within a
distributed control system. A number of industrial communication protocols,
such as PROFINET or MODBUS/TCP, use TCP/IP as their base communication
protocol. If you do wish to make a custom protocol, then RL-TCPnet has a low
level “Sockets” API. This allows you to send and receive raw TCP and UDP
frames. To demonstrate how the Sockets Library is used, we will establish a
TCP/IP link between two microcontrollers and send custom data packets as UDP
and TCP frames.
switch (event)
}
case DNS_EVT_SUCCESS:
case DNS_EVT_NONAME:
case DNS_EVT_TIMEOUT:
case DNS_EVT_ERROR:
break;
break;
break;
return;
{
// Success: IP address pointed at by *ip
// Name does not exist in DNS database.
// DNS sever timeout
// DNS protocol error
Chapter 4. RL-TCPnet Introduction
{