AX88850 ASIX [ASIX Electronics Corporation], AX88850 Datasheet - Page 20

• Manufacturer Part Number: AX88850
• Description: 100BASE-TX/FX Repeater Controller
• Manufacturer: ASIX [ASIX Electronics Corporation]

3.4 Jabber State Machine
To prevent an illegally long reception of data from reaching the repeater unit, each port has its own jabber timer. If a
reception exceeds this duration(64K bit times for AX88850), the jabber condition will be detected. In this condition,
repeater unit will disable receive and transmit packets for the jabbered port and the other ports remain the normal
operation.
When the carrier is no longer detected for the jabbered port or reset the repeater, the jabber function will be clear and
re-enable reception and transmission.
3.5 Partition State Machine
The partition state machine is used to protect network from be upset by a port suffering continuous collision, each port
uses a partition state machine to detect and prevent this condition. When a port is suffering from continuous 32 or
64 times of collisions by CCLimits. Then it goes to Partition State. The port entering Partition State will be released
until a packet without collision more than 512 bit times or after power-on reset.
Partition function is enabled by default, and CCLimits is 64 by default. Enable/Disable partition function
(DIS_PART) and option of CCLimits to be 64 or 32 (COL_LIMIT32) are selected by station management access
logic.
AX88850
Collision State
The Collision State happens when these conditions exists:
a.
b.
c.
There are two or more signals high among M0_CRS[7:0],M1_CRS[7:0],CRS[1:0]. Or receive
collision messages from /IR_ACTO[7:0] in MII mode.
At least two ports of PCS ports receive /J/K/ code group or receive collision message from
/IR_ACTO[7:0] in PCS mode.
Only one carrier exists but RXDV still low exceeds 5 clock cycles. The repeater sends collision
pattern to all ports, that is, M0_TXEN[7:0] and M1_TXEN[7:0] all become high during collision
state.
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ASIX ELECTRONICS CORPORATION
PRELIMINARY