KSZ8862 Micrel Semiconductor, KSZ8862 Datasheet - Page 39

• Manufacturer Part Number: KSZ8862
• Description: 2-port Ethernet Switch With Non-pci Interface And Fiber Support
• Manufacturer: Micrel Semiconductor

The transmit Byte Count specifies the total number of bytes to be transmitted from the TXQ. Its format is given in Table 5.
The data area contains six bytes of Destination Address (DA) followed by six bytes of Source Address (SA), followed by a
variable-length number of bytes. On transmit, all bytes are provided by the CPU, including the source address. The
KSZ8862M does not insert its own source address. The 802.3 Frame Length word (Frame Type in Ethernet) is not
interpreted by the KSZ8862M. It is treated transparently as data for transmit operations.
Receive Queue (RXQ) Frame Format
The frame format for the receive queue is shown in Table 6. The first word contains the status information for the frame
received. The second word is the total number of bytes of the RX frame. Following that is the packet data area. The
packet data area holds the frame itself. It may or may not include the CRC checksum depending on whether hardware
CRC stripping is enabled.
Micrel, Inc.
April 2007
Bit
15-11
10-0
Description
Reserved
TXBC Transmit Byte Count
Transmit Byte Count. Hardware uses the byte count information to conserve the TX buffer
memory for better utilization of the packet memory.
Note: The hardware behavior is unknown if an incorrect byte count information is written to
this field. Writing a 0 value to this field is not permitted.
Packet Memory
Address Offset
0
2
4 - up
Table 6. Receive Queue Frame Format
Table 5. Transmit Byte Count Format
Bit 15
2
Status Word
Byte Count
Packet Data
(maximum size is 1916)
nd
Byte
39
1
st
Bit 0
Byte
KSZ8862-16/32MQL
M9999-040407-3.0