DP83848HSQ National Semiconductor, DP83848HSQ Datasheet - Page 22

• Manufacturer Part Number: DP83848HSQ
• Description: IC, TRANSCEIVER, ENET PHYTER, 40LLP
• Manufacturer: National Semiconductor

Specifications of DP83848HSQ

• 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 +125°C
• Digital Ic Case Style: LLP
• No. Of: RoHS Compliant
• Interface Type: MII Serial, RMII
• Rohs Compliant: Yes

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3.3.3 Serial Management Preamble Suppression
The DP83848H supports a Preamble Suppression mode
as indicated by a one in bit 6 of the Basic Mode Status
Register (BMSR, address 01h.) If the station management
entity (i.e. MAC or other management controller) deter-
mines that all PHYs in the system support Preamble Sup-
pression by returning a one in this bit, then the station
management entity need not generate preamble for each
management transaction.
The DP83848H requires a single initialization sequence of
32 bits of preamble following hardware/software reset. This
MDIO
MDIO
MDC
MDC
MDIO
(STA)
(PHY)
(STA)
Z
Idle
Z
Idle
Z
Z
0
0
Start
Start
1 1
1
Opcode
(Read)
Opcode
(Write)
0
0 0
1
0
(PHYAD = 0Ch)
(PHYAD = 0Ch)
PHY Address
PHY Address
1 1 0 0 0 0 0 0 0
1 1 0 0 0 0 0 0 0
Figure 5. Typical MDC/MDIO Write Operation
Figure 4. Typical MDC/MDIO Read Operation
Register Address
Register Address
(00h = BMCR)
(00h = BMCR)
Z
Z
Z
22
1
TA
0 0 0 1 1 0 0 0 1 0 0 0 0 0 0 0 0
TA
requirement is generally met by the mandatory pull-up
resistor on MDIO in conjunction with a continuous MDC, or
the management access made to determine whether Pre-
amble Suppression is supported.
While the DP83848H requires an initial preamble
sequence of 32 bits for management initialization, it does
not require a full 32-bit sequence between each subse-
quent transaction. A minimum of one idle bit between man-
agement transactions is required as specified in the IEEE
802.3u specification.
0 0 0
0 0
0 0 0
Register Data
Register Data
0
0 0 0 0 0 0 0 0
Z
Idle
Z
Z
Idle
Z