MC9S12NE64_06 Datasheet, PDF (370/554 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 12 Ethernet Physical Transceiver (EPHYV2)
If the auto-negotiation mode of operation is desired, the ANDIS bit in the EPHYCTL0 must be set to 0
and the DIS100 and DIS10 bits must be cleared prior to setting EPHYEN to 1. Refer to Section 12.4.2,
“Auto-Negotiation,” for more information on auto-negotiation operation.
If the mode of operation will be set manually, the ANDIS bit must be set to 1 in the EPHYCTL0 register
and the DIS100 and DIS10 bits must be cleared prior to setting EPHYEN to 1. After the EPHYEN bit has
been set and the start-up delay period is completed, the mode of operation can be configured through the
MII registers. Table 12-3 summarizes the MII register configuration and operational modes.
Table 12-3. Operational Configuration While Auto-Negotiation is Disabled¹
Bit 0.12
Auto
Neg.
0
0
0
0
Bit 0.13
Data
Rate
0
0
1
1
Bit 0.8
Duplex
1
0
1
1
0
1
1
0
1
1
0
1
1
0
1
0
1 _{Symbol mode is not supported.}
Bit 18.6
Encoder
Bypass
X
X
0
1
1
1
1
0
Bit 18.5
Scrambler
Bypass
X
X
0
0
0
1
1
0
Bit 18.7
Symbol
Unalign
X
X
0
0
1
0
1
0
Operation
10BASE-T full-duplex
10BASE-T half-duplex
100BASE-TX full-duplex
100BASE-TX full-duplex with encoder
bypass (symbol mode) — aligned
100BASE-TX full-duplex with encoder
bypass (symbol mode) — unaligned
100BASE-TX full-duplex with scrambler
and encoder bypassed (symbol mode),
aligned
100BASE-TX full-duplex with scrambler
and encoder bypassed (symbol mode),
unaligned
100BASE-TX half-duplex
12.4.2 Auto-Negotiation
Auto-negotiation is used to determine the capabilities of the link partner. Auto-negotiation is compliant
with IEEE 802.3 clause 28. In this case, the PHY will transmit fast link pulse (FLP) bursts to share its
capabilities with the link partner.
If the link partner is also capable of performing auto-negotiation, it will also send FLP bursts. The
information shared through the FLP bursts will allow both link partners to find the highest common mode
(if it exists).
If no common mode is found, the remote fault bit (1.4) will be set. A remote fault is defined as a condition
in which the PHY and the link partner cannot establish a common operating mode. Configuring
auto-negotiation advertisement register sets the different auto-negotiation advertisement modes.
If the link partner does not support auto-negotiation, it will transmit either normal link pulses (NLP) for
10 Mbps operation, or 100 Mbps idle symbols. Based on the received signal, the PHY determines whether
the link partner is 10 Mbps capable or 100 Mbps capable. The ability to do this is called parallel detection.
If using parallel detection, the link will be configured as a half-duplex link. After parallel detection has
established the link configuration, the remote fault bit will be set if the operating mode does not match the
pre-set operating modes.
MC9S12NE64 Data Sheet, Rev. 1.1
370
Freescale Semiconductor