W5100E01-AVR WIZnet, W5100E01-AVR Datasheet - Page 80

• Manufacturer Part Number: W5100E01-AVR
• Description: Development Boards & Kits - AVR W5100 EVAL BOARD BASED ON AVR
• Manufacturer: WIZnet

Specifications of W5100E01-AVR

• Rohs: yes
• Product: Development Boards
• Tool Is For Evaluation Of: ATMEGA128
• Core: AVR8
• Interface Type: LAN, RS-232
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 bit

getIP_DHCPS() initializes W5100 using setIP(),setMACAddr(),and etc, and it initializes ‘dhcp_state’ variable
as DHCP client program state to ‘STATE_DHCP_DISCOVER’. After the initialization, it calls
send_DHCP_DISCOVER() to transfer a DHCP DISCOVERY message to DHCP server.
After transmitting DISCOVERY DHCP message, it initializes timer variables which are the leased time of
network information received from DHCP server by calling reset_DHCP_time() and uses ‘DHCP Timer’ for 1-
sec interval using set_timer(). After the initialization of DHCP_Timeout with 0, it waits for DHCP message to
be received from DHCP server as long as the ‘DHCP_WAIT_TIME’ defines and as many as the
‘MAX_DHCP_RETRY’defines. While waiting for ‘DHCP_WAIT_TIME & MAX_DHCP_RETRY’ time, it
continuously checks if dhcp_state is changed to STATE_DHCP_LEASED through check_DHCP_state().
STATE_DHCP_LEASED state represents the network information and means that getIP_DHCP() is done
successfully. If network information is not obtained from DHCP Server during the waiting time for
‘DHCP_WAIT_TIME & MAX_DHCP_RETRY’, check_DHCP_state() sets DHCP_Timeout to 1. When
N
dhcp_state != STATE_DHCP_LEASED
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dhcp_state = STATE_DHCP_DISCOVER
Reset timeout value & retry count
send_DHCP_DISCOVER()
Set Timer for DHCP Client
DHCP_Timeout == 1
check_DHCP_state()
Find a DHCP Server
reset_DHCP_time()
DHCP_Timeout = 0
RETURN Success
Check dhcp_state
getIP_DHCPS()
set_timer(1s)
dhcp_state =
<Fig 3.29: getIP_DHCPS()>
Y
N
Y
Kill Timer for DHCP Client
RETURN Fail
kill_timer()
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