adm6999ux Infineon Technologies Corporation, adm6999ux Datasheet - Page 24

• Manufacturer Part Number: adm6999ux
• Description: Adm6999u 9 Port 10/100 Mb/s Single Chip Ethernet Switch Controller
• Manufacturer: Infineon Technologies Corporation

2. If the DA is an UNICAST address and the address was not found, the ADM6999U/UX treats it as a multicast
3. If the DA is a Multicast address, the packet is forwarded across the bridge.
4. If the DA is PAUSE Command (01-80-C2-00-00-01), then this packet will be dropped by ADM6999U/UX.
5. ADM6999U/UX will forward the packet with DA of ( 01-80-C2-00-00-00 ), filter out the packet with DA of ( 01-
3.4.1.3
Address aging is supported for topology changes such as an address moving from one port to the other. When
this happens, the ADM6999U/UX internally has a 300 seconds timer will aged out (remove) the address from the
address table. Aging function can be enabled/disabled by user. Normally, disabling aging function is for security
purpose.
3.4.1.4
The ADM6999U/UX implements the truncated exponential back off algorithm compliant to the IEEE802.3
CSMA/CD standard. ADM6999U/UX will restart the back off algorithm by choosing 0-9 collision counts. The
ADM6999U/UX resets the collision counter after 16 consecutive retransmit trials.
3.4.1.5
IPG is the idle time between any two successive packets from the same port. The typical number is 96-bits time.
The value is 9.6µs for 10Mbps ETHERNET, and 960ns for 100Mbps fast ETHERNET. ADM6999U/UX provides
the option of a 92-bit gap in EEPROM to prevent packet lost when Flow Control is turned off and clock P.P.M.
value differs.
3.4.1.6
The ADM6999U/UX will discard all illegal frames such as runt packet (less than 64 bytes), oversize packet (greater
than 1518 or 1522 bytes) and bad CRC. Dribbling packing with good CRC value will accept by ADM6999U/UX. In
case of bypass mode enabled, ADM6999U/UX will support tag and untagged packets with size up to 1522 bytes.
In case of non-bypass mode, ADM6999U/UX will support tag packets up to 1526bytes, and untagged packets up
to 1522bytes.
3.4.1.7
Back Pressure function is supported for half-duplex operation. When the ADM6999U/UX cannot allocate a
receiving buffer for an incoming packet (buffer full), the device will transmit a jam pattern on the port, thus forcing
a collision. Back Pressure is enabled by the BPEN set during RESET asserting. An Infineon-ADMtek Co Ltd
proprietary algorithm is implemented inside the ADM6999U/UX to prevent back pressure function causing HUB
partitioned under heavy traffic environment and reduce the packet lost rate to increase the whole system
performance.
3.4.1.8
When full duplex port runs out of its receiving buffer, a PAUSE packet command will be issued by ADM6999U/UX
to notice the packet sender to pause transmission. This frame based flow control is totally compliant to IEEE
802.3x. ADM6999U/UX can issue or receive pause packet.
Data Sheet
packet and forwards across the bridge.
ADM6999U/UX can issue and learn PAUSE command.
80-C2-00-00-01 ), and forward the packet with DA of ( 01-80-C2-00-00-02 ~ 01-80-C2-00-00-0F )
Address Aging
Back off Algorithm
Inter-Packet Gap (IPG)
Illegal Frames
Half Duplex Flow Control
Full Duplex Flow Control
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Rev. 1.42, 2005-11-25
ADM6999U/UX
Data Sheet
Descriptions