DP83848VYB National Semiconductor, DP83848VYB Datasheet - Page 13

• Manufacturer Part Number: DP83848VYB
• Description: TRANSCEIVER, ENET PHY, 10/100, 48LQFP
• Manufacturer: National Semiconductor

Specifications of DP83848VYB

• Data Rate: 100Mbps
• No. Of Ports: 1
• Ethernet Type: IEEE 802.3u
• Supply Current: 92mA
• Supply Voltage Range: 3V To 3.6V
• Operating Temperature Range: -40°C To +105°C
• Digital Ic Case Style: LQFP
• No.: RoHS Compliant
• Interface Type: MII Serial, RMII
• Rohs Compliant: Yes
• Lead Free Status / Rohs Status: Not Compliant

2.0 Configuration
This section includes information on the various configuration
options available with the DP83848VYB. The configuration
options described below include:
— Auto-Negotiation
— PHY Address and LEDs
— Half Duplex vs. Full Duplex
— Isolate mode
— Loopback mode
— BIST
2.1 AUTO-NEGOTIATION
The Auto-Negotiation function provides a mechanism for ex-
changing configuration information between two ends of a link
segment and automatically selecting the highest performance
mode of operation supported by both devices. Fast Link Pulse
(FLP) Bursts provide the signalling used to communicate Au-
to-Negotiation abilities between two devices at each end of a
link segment. For further detail regarding Auto-Negotiation,
refer to Clause 28 of the IEEE 802.3u specification. The
DP83848VYB supports four different Ethernet protocols (10
Mb/s Half Duplex, 10 Mb/s Full Duplex, 100 Mb/s Half Duplex,
and 100 Mb/s Full Duplex), so the inclusion of Auto-Negotia-
tion ensures that the highest performance protocol will be
selected based on the advertised ability of the Link Partner.
The Auto-Negotiation function within the DP83848VYB can
be controlled either by internal register access or by the use
of the AN_EN, AN1 and AN0 pins.
2.1.1 Auto-Negotiation Pin Control
The state of AN_EN, AN0 and AN1 determines whether the
DP83848VYB is forced into a specific mode or Auto-Negoti-
ation will advertise a specific ability (or set of abilities) as given
in Table 1. These pins allow configuration options to be se-
lected without requiring internal register access.
The state of AN_EN, AN0 and AN1, upon power-up/reset,
determines the state of bits [8:5] of the ANAR register.
The Auto-Negotiation function selected at power-up or reset
can be changed at any time by writing to the Basic Mode
Control Register (BMCR) at address 0x00h.
2.1.2 Auto-Negotiation Register Control
When Auto-Negotiation is enabled, the DP83848VYB trans-
mits the abilities programmed into the Auto-Negotiation Ad-
vertisement register (ANAR) at address 04h via FLP Bursts.
Any combination of 10 Mb/s, 100 Mb/s, Half-Duplex, and Full
Duplex modes may be selected.
AN_EN
AN_EN
0
0
0
0
1
1
1
1
TABLE 1. Auto-Negotiation Modes
AN1 AN0
AN1 AN0
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
10BASE-T, Half-Duplex
10BASE-T, Full-Duplex
100BASE-TX, Half-Duplex
100BASE-TX, Full-Duplex
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
10BASE-T Half-Duplex
100BASE-TX, Half-Duplex
10BASE-T, Half/Full-Duplex
100BASE-TX, Half/Full-Duplex
Advertised Mode
Forced Mode
13
Auto-Negotiation Priority Resolution:
1.
2.
3.
4.
The Basic Mode Control Register (BMCR) at address 00h
provides control for enabling, disabling, and restarting the
Auto-Negotiation process. When Auto-Negotiation is dis-
abled, the Speed Selection bit in the BMCR controls switching
between 10 Mb/s or 100 Mb/s operation, and the Duplex
Mode bit controls switching between full duplex operation and
half duplex operation. The Speed Selection and Duplex Mode
bits have no effect on the mode of operation when the Auto-
Negotiation Enable bit is set.
The Link Speed can be examined through the PHY Status
Register (PHYSTS) at address 10h after a Link is achieved.
The Basic Mode Status Register (BMSR) indicates the set of
available abilities for technology types, Auto-Negotiation abil-
ity, and Extended Register Capability. These bits are perma-
nently set to indicate the full functionality of the DP83848VYB
(only the 100BASE-T4 bit is not set since the DP83848VYB
does not support that function).
The BMSR also provides status on:
•
•
•
•
The Auto-Negotiation Advertisement Register (ANAR) indi-
cates the Auto-Negotiation abilities to be advertised by the
DP83848VYB. All available abilities are transmitted by de-
fault, but any ability can be suppressed by writing to the
ANAR. Updating the ANAR to suppress an ability is one way
for a management agent to change (restrict) the technology
that is used.
The Auto-Negotiation Link Partner Ability Register (ANLPAR)
at address 0x05h is used to receive the base link code word
as well as all next page code words during the negotiation.
Furthermore, the ANLPAR will be updated to either 0081h or
0021h for parallel detection to either 100 Mb/s or 10 Mb/s re-
spectively.
The Auto-Negotiation Expansion Register (ANER) indicates
additional Auto-Negotiation status. The ANER provides sta-
tus on:
•
•
•
•
•
2.1.3 Auto-Negotiation Parallel Detection
The DP83848VYB supports the Parallel Detection function as
defined in the IEEE 802.3u specification. Parallel Detection
requires both the 10 Mb/s and 100 Mb/s receivers to monitor
the receive signal and report link status to the Auto-Negotia-
tion function. Auto-Negotiation uses this information to con-
figure the correct technology in the event that the Link Partner
does not support Auto-Negotiation but is transmitting link sig-
nals that the 100BASE-TX or 10BASE-T PMAs recognize as
valid link signals.
Whether or not Auto-Negotiation is complete
Whether or not the Link Partner is advertising that a
remote fault has occurred
Whether or not valid link has been established
Support for Management Frame Preamble suppression
Whether or not a Parallel Detect Fault has occurred
Whether or not the Link Partner supports the Next Page
function
Whether or not the DP83848VYB supports the Next Page
function
Whether or not the current page being exchanged by Auto-
Negotiation has been received
Whether or not the Link Partner supports Auto-Negotiation
100BASE-TX Full Duplex (Highest Priority)
100BASE-TX Half Duplex
10BASE-T Full Duplex
10BASE-T Half Duplex (Lowest Priority)
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