adm6996f Infineon Technologies Corporation, adm6996f Datasheet - Page 29

• Manufacturer Part Number: adm6996f
• Description: 6 Port 10/100 Mb/s Single Chip Ethernet Switch Controller
• Manufacturer: Infineon Technologies Corporation

ADM6996F
Infineon-ADMtek Co Ltd.
3.15.6 Illegal Frames
3.15.7 Half Duplex Flow Control
3.15.8 Full Duplex Flow Control
3.15.9 Broadcast Storm filter
3.16 Auto TP MDIX function
The ADM6996F 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 ADM6996F. In case of bypass mode enabled,
ADM6996F will support tag and untagged packets with size up to 1522 bytes. In case of
non-bypass mode, ADM6996F will support tag packets up to 1526bytes, untagged
packets up to 1522bytes.
Back Pressure function is supported for half-duplex operation. When the ADM6996F
cannot allocate a receive 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 ADM6996F to prevent back pressure function cause
HUB partitioned under heavy traffic environment and reduce the packet lost rate to
increase the whole system performance.
When full duplex port run out of its receive buffer, a PAUSE packet command will be
issued by ADM6996F to notice the packet sender to pause transmission. This frame
based flow control is totally compliant to IEEE 802.3x. ADM6996F can issue or receive
pause packet.
If Broadcast Storming filter is enable, the broadcast packets over the rising threshold
within 50 ms will be discarded by the threshold setting. See EEPROM Reg.10h.
Broadcast storm mode after initial:
- time interval : 50ms
Per Port Rising Threshold
All 100TX
Not
100TX
At normal application which Switch connect to NIC card is by one by one TP cable. If
the max. packet number = 7490 in 100Base, 749 in 10Base
All
00
Disable 10% 20%
Disable 1%
01
10
2%
11
40%
4%
Per Port Falling Threshold
All 100TX
Not
100TX
All
00
Disable 0.5% 1%
Disable 5%
01
10
10%
Function Description
11
20%
2%
3-11