KS8842-16MQL Micrel Inc, KS8842-16MQL Datasheet - Page 32
![IC SWITCH 10/100 16BIT 128PQFP](/photos/6/81/68152/576-128-pqfp_sml.jpg)
KS8842-16MQL
Manufacturer Part Number
KS8842-16MQL
Description
IC SWITCH 10/100 16BIT 128PQFP
Manufacturer
Micrel Inc
Specifications of KS8842-16MQL
Applications
*
Mounting Type
Surface Mount
Package / Case
128-MQFP, 128-PQFP
Number Of Primary Switch Ports
2
Internal Memory Buffer Size
32
Operating Supply Voltage (typ)
3.3V
Fiber Support
Yes
Integrated Led Drivers
Yes
Phy/transceiver Interface
MII
Power Supply Type
Analog/Digital
Package Type
PQFP
Data Rate (typ)
10/100Mbps
Vlan Support
Yes
Operating Temperature (max)
70C
Operating Temperature (min)
0C
Pin Count
128
Mounting
Surface Mount
Jtag Support
No
Operating Supply Voltage (max)
3.5V
Operating Supply Voltage (min)
3.1V
Operating Temperature Classification
Commercial
Data Rate
100Mbps
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
KS8842-PMQL-EVAL - EVAL KIT EXPERIMENTAL KS8842KS8842-16MQL-EVAL - EVAL KIT EXPERIMENTAL KS8842
Lead Free Status / RoHS Status
Not Compliant, Lead free / RoHS Compliant
Other names
576-1458
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Usage
LinkMD can be run at any time by making sure Auto MDIX has been disabled. To disable Auto-MDIX, write a ‘1’ to
P1CR4[10] for port 1 or P2CR4[10] for port 2 to enable manual control over the pair used to transmit the LinkMD pulse.
The self-clearing cable diagnostic test enable bit, P1VCT[15] for port 1 or P2VCT[15] for port 2 , is set to ‘1’ to start the
test on this pair.
When bit P1VCT[15] or P2VCT[15] returns to ‘0’, the test is complete. The test result is returned in bits P1VCT[14:13] or
P2VCT[14:13] and the distance is returned in bits P1VCT[8:0] or P2VCT[8:0]. The cable diagnostic test results are as
follows:
If P1VCT[14:13]=11 or P2VCT[14:13]=11, this indicates an invalid test, and occurs when the KSZ8842M is unable to shut
down the link partner. In this instance, the test is not run, as it is not possible for the KSZ8842M to determine if the
detected signal is a reflection of the signal generated or a signal from another source.
Cable distance can be approximated by the following formula:
P1VCT[8:0] X 0.4m for port 1 cable distance
P2VCT[8:0] X 0.4m for port 2 cable distance
This constant may be calibrated for different cabling conditions, including cables with a velocity of propagation that varies
significantly from the norm.
Functional Overview: MAC and Switch
Address Lookup
The internal lookup table stores MAC addresses and their associated information. It contains a 1K entry unicast address
learning table plus switching information.
The KSZ8842M is guaranteed to learn 1K addresses and distinguishes itself from hash-based lookup tables, which
depending on the operating environment and probabilities, may not guarantee the absolute number of addresses it can
learn.
Learning
The internal lookup engine updates its table with a new entry if the following conditions are met:
The lookup engine inserts the qualified SA into the table, along with the port number and time stamp. If the table is full, the
last entry of the table is deleted to make room for the new entry.
Migration
The internal lookup engine also monitors whether a station has moved. If a station has moved, it updates the table
accordingly. Migration happens when the following conditions are met:
The lookup engine updates the existing record in the table with the new source port information.
Aging
The lookup engine updates the time stamp information of a record whenever the corresponding SA appears. The time
stamp is used in the aging process. If a record is not updated for a period of time, the lookup engine removes the record
from the table. The lookup engine constantly performs the aging process and continuously removes aging records. The
aging period is about 200 seconds. This feature can be enabled or disabled through Global Register SGCR1[10].
Micrel, Inc.
October 2007
1. The received packet's Source Address (SA) does not exist in the lookup table.
2. The received packet is good without receiving errors; the packet size is legal length.
1. The received packet's SA is in the table but the associated source port information is different.
2. The received packet is good without receiving errors; the packet size is legal length.
00 = Valid test, normal condition
01 = Valid test, open circuit in cable
10 = Valid test, short circuit in cable
11 = Invalid test, LinkMD failed
32
KSZ8842-16/32 MQL/MVL/MVLI/MBL
M9999-102207-1.9