LAN89218AQ SMSC, LAN89218AQ Datasheet - Page 34

• Manufacturer Part Number: LAN89218AQ
• Description: Ethernet ICs High Perform Chip 10/100 NonPCI Cntrl
• Manufacturer: SMSC

Specifications of LAN89218AQ

• Ethernet Connection Type: 10BASE-T, 100BASE-TX
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Product: Ethernet Controllers
• Standard Supported: IEEE802.3, IEEE802.3u
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 3 V
• Maximum Operating Temperature: + 85 C
• Package / Case: TQFP-100
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Revision 1.3 (02-23-10)
1DWORD
1DWORD
DST
0
The RXCOE supports a maximum of two VLAN tags. If there are more than two VLAN tags, the VLAN
protocol identifier for the third tag is treated as an Ethernet type field. The checksum calculation will
begin immediately after the type field.
The RXCOE resides in the RX path within the MAC. As the RXCOE receives an Ethernet frame it
calculates the 16-bit checksum. The RXCOE passes the Ethernet frame to the RX Data FIFO with the
checksum appended to the end of the frame. The RXCOE inserts the checksum immediately after the
last byte of the Ethernet frame. The packet length field in the RX status word (refer to
will indicate that the frame size has increased by two bytes to accommodate the checksum.
The COE inserts the checksum immediately after the last byte of the Ethernet frame and before it
transmits the status word. The status word is modified to indicate the frame size has increased by two
bytes. The Packet Length field in the RX status word for the associated frame will indicate that the
frame size has increased by two bytes to accommodate the checksum.
Note: When enabled, the RXCOE calculates a checksum for every received frame.
Setting the RXCOE_EN bit in the
RXCOE, and the RXCOE_MODE bit selects the operating mode. When the RXCOE is disabled, the
the received frame and associated status must not be modified and received data is simply passed
through the RXCOE.
{DSAP, SSAP, CTRL, OUI[23:16]}
DST
0
{DSAP, SSAP, CTRL, OUI[23:16]}
1
SRC
Figure 3.7 Ethernet Frame with multiple VLAN Tags and SNAP Header
1
SRC
2
2
Figure 3.6 Ethernet Frame with VLAN Tag and SNAP Header
8
1
0
0
4
8
1
0
0
V
I
D
3
V
I
D
8
1
0
0
5
L
e
n
V
I
D
4
L
e
n
S
N
A
P
0
6
S
N
A
P
0
5
S
N
A
P
1
7
High Performance Single-Chip 10/100 Ethernet Controller for Automotive Applications
S
N
A
P
1
6
8
COE_CR—Checksum Offload Engine Control Register
DATASHEET
{OUI[15:0], PID[15:0]}
{OUI[15:0], PID[15:0]}
34
Calculate Checksum
Calculate Checksum
L3 Packet
L3 Packet
C
F
S
SMSC LAN89218
Section
F
C
S
enables the
Datasheet
3.13.3)