MC9S12NE64_06 Datasheet, PDF (373/554 Pages) Freescale Semiconductor, Inc – Microcontrollers

Functional Description
Link Integrity Test: Used to determine whether the 10BASE-T link is operational. If neither data nor a
link pulse is received for 64 ms, then the link is considered down. While the link is down, the transmit,
loopback, collision detect, and SQE functions are disabled. The link down state is exited after receiving
data or four link pulses.
Jabber: Prevents the transmitter from erroneously transmitting for too long a period. The maximum time
the device can transmit is 50,000 bit times. When the jabber timer is exceeded, the transmit output goes
idle for 0.525 s.
This function can be disabled with the jabber inhibit register bit (18.10).
Squelch: Used to determine whether active data, a link pulse, or an idle condition exists on the 10BASE-T
receive channel. While an idle or link pulse condition exists, a higher squelch level is used for greater noise
immunity. The squelch output is used to determine when the Manchester decoder should operate. The
output is also used to determine when an end of packet is received.
Polarity Check: By examining the polarity of the received link pulses, EPHY can determine whether the
received signal is inverted. If the pulses are inverted, this function changes the polarity of the signal.This
feature is activated if eight inverted link pulses are received or four frames with inverted EOF are
encountered.
Manchester Decoder and Timing Recovery: Decodes the Manchester encoded data. The receive data
and clock are recovered during this process.
Serial to Parallel: Converts the serial bit stream from the Manchester decoder to the required MII parallel
format.
PMD Sublayer: Transmits and receives signals compliant with IEEE 802.3, Section 14.
Line Transmitter and Line Receiver: These analog blocks allow the EPHY to drive and receive data
from the 10BASE-T media.
12.4.4 100BASE-TX
100BASE-TX specifies operation over two pairs of category 5 unshielded twisted-pair cable (UTP).
The EPHY implementation includes the physical coding sublayer (PCS), the physical medium attachment
(PMA), and the physical medium dependent (PMD) sublayer.
The block diagram for 100BASE-TX operation is shown in Figure 12-22.
MC9S12NE64 Data Sheet, Rev. 1.1
Freescale Semiconductor
373