s3c4510b Samsung Semiconductor, Inc., s3c4510b Datasheet - Page 270

• Manufacturer Part Number: s3c4510b
• Description: 16/32-bit Risc Microcontroller
• Manufacturer: Samsung Semiconductor, Inc.

ETHERNET CONTROLLER
Options That Affect the Standard MAC Frame
There are a number of factors and options which can affect the standard MAC frame, as described in Table 7-44:
— Some PHYs may deliver a longer or shorter preamble.
— Short packet mode permits LLC data fields with less than 46 bytes. Options are available to suppress
— Long packet mode supports LLC data fields with more than 1500 bytes. An option is also available to support
— "No CRC" mode suppresses the appending of a CRC field.
— "Ignore CRC" mode allows the reception of packets without valid CRC fields.
7-48
padding and to support the reception of short packets.
to reception of long packets.
DSAP = Destination service access point
CTRL = Control field
OUI = Origanizationally unique identifier
SFD = Starting frame delimiter
Preamble
Transmitter,
Stripped by
Added by
Receiver
7 bit
Figure 7-15. Fields of an IEEE802.3/Ethernet Packet (Frame)
OR
S
F
D
1
Data frame (delivered to user)
Destination
Address
6 bytes
DSAP
DSAP
1 byte
LLC header
Packet (Encoded on the Medium)
1 byte
SSAP
SSAP
Data Frame (sent by user)
Address
6 bytes
Source
1 byte 3 bytes 2 bytes
CTRL
CTRL
SSAP = Source service access point
SNAP = Subnetwork access protocol
PID = Protocol identifier
LLC = Logical lick control
FCS = Frame check sequence
Length or
2 bytes
OUI
type
SNAP
LLC information field
PID
IP/X.25/......
LLC data
46-1500
bytes
IP/X.25/......
Added by transmitter
Optionaly stripped
PAD
0-46
by receiver
4 bytes
FCS
S3C4510B