EVB-B1+ WIZnet, EVB-B1+ Datasheet - Page 65

• Manufacturer Part Number: EVB-B1+
• Description: Development Boards & Kits - ARM W3150A+EVAL BOARD BASED ON AVR
• Manufacturer: WIZnet

Specifications of EVB-B1+

• Rohs: yes
• Product: Evaluation Boards
• Interface Type: RS-232, SPI
• Operating Supply Voltage: 3.3 V, 5 V
• Data Bus Width: 8 bit
• Dimensions: 50 mm x 40 mm
• Processor Series: ATmega128

If the udp socket is in SOCK_CLOSED status, socket() is called using SOCK_DGRAM, Port Number, and
Option Flag as the elements to create the UDP socket.
UDP communication, as opposed to TCP, is a datagram communication without the requirement of
connection process. So, direct data communication is possible immediately after socket creation. After
creation of UDP socket, the udp socket status will be changed from SOCK_CLOSED to SOCK_UDP.
Here, not like TCP for data communication which uses send() and recv(), sendto() and recvfrom() are used.
This is because TCP is 1-to-1 communication method of which destination is known but UDP is 1-to-many
communication without connection procedure. sendto() sends data to specific port of specific destination that
is sent as an element, recvfrom() is used to receive the incoming data from temporary port. Destination
information from recvfrom() is informed to user using destip and destport which are sent as elements.
In loopback_udp(), there is no example of using close(), but in case that the UDP communication is not
needed anymore, close() can be always called to close the udp socket.
3.2.6.4.
Web Server program is a TCP server program using HTTP protocol which is used on TCP protocol. Before
building Web server program, message structure of HTTP protocol that is transmitted between Web server
and Web client(Web browser) are needed to be understood.
HTTP, which stands for Hyper Text Transfer Protocol, is a protocol used in Internet for transferring between
void loopback_udp(u_char ch)
u_int select
(SOCKET s, u_char func)
u_char
u_char
u_char flag)
u_int sendto(SOCKET s,
const u_char * buf, u_int len,
u_char * addr, u_int port)
u_int recvfrom(SOCKET s,
u_char * buf, u_int len, u_char *
addr, u_int * port)
void close(SOCKET s)
Web Server
Function Name
protocol,
socket(SOCKET
© Copyright 2006 WIZnet Co., Inc. All rights reserved.
<Table 3-25: Reference Functions in loopback_udp()>
u_int
port,
s,
Loopback udp program
Gets the socket status, the size of
transferable and received data.
Creates related socket as TCP/UDP/IP.
Sends data to specific port of specific
destination
Sends
destination related socket
Close related socket
data
Description
to
related socket
any
port
of
any
app/loopback.c
iinChip/socket.c
iinChip/socket.c
iinChip/socket.c
iinChip/socket.c
iinChip/socket.c
Location
55