STE400P STMicroelectronics, STE400P Datasheet - Page 23

• Manufacturer Part Number: STE400P
• Description: STE400P - 4 PORT 10-100 FAST ETHERNET TRANSCEIVER - PHY DATASHEET
• Manufacturer: STMicroelectronics

pulled down through resistors as shown in the following circuits.
8.11 Preamble Suppression
Preamble suppression mode in the STE400P is indicated by a one in bit six of the PR1 Register. If it is deter-
mined that all PHY devices in the system support preamble suppression, then a preamble is not necessary for
each management transaction. The first transaction following power-up/hardware reset requires 32 bits of pre-
amble. The full 32 bit preamble is not required for each additional transaction. The STE400P will respond to
management accesses without preamble, but a minimum of one idle bit between management transactions is
required as specified in IEEE 802.3u.
8.12 Remote Fault
The remote fault function indicates to a link partner that a fault condition has occurred by using the Remote Fault
bit, which is encoded in bit 13 of the Link Code Word. A local device indicates to its link partner that it has found
a fault by setting the Remote Fault bit in the Auto-Negotiation register to logic one and renegotiating with the
link partner. The Remote Fault bit remains at logic one until successful negotiation with the Link Code Word
occurs. The bit will then return to 0. When the message is sent that the Remote Fault bit is set to logic one, the
device will set the Remote Fault bit in the MII to logic one if the management function is present.
8.13 Transmit Isolation
I/O PIN
RxD
TxD
10k
Logic Level 1
4/5
4/5
STA/STE
MII
Vcc
1 PORT OF STE400P
STEPHY1
TX(100MHz)/TP(10MHz)
10k
Ethernet
Logic Level 0
ttp
tpn
I/O PIN
STE400P
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