DP83953VUL National Semiconductor, DP83953VUL Datasheet - Page 27

• Manufacturer Part Number: DP83953VUL
• Description: IC CTRLR RIC REPEATER 160-PQFP
• Manufacturer: National Semiconductor

Specifications of DP83953VUL

• Controller Type: Ethernet Repeater Interface Controller
• Interface: IEEE 802.3
• Voltage - Supply: 4.75 V ~ 5.25 V
• Current - Supply: 870mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 160-MQFP, 160-PQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP83953VUL

4.0 Functional Description
4.5 Description Of Hardware Connection For In-
ter-ric Bus
When considering the hardware interface, the Inter-RIC
bus may be viewed as consisting of three groups of signals:
1. Port Arbitration chain, namely: ACKI and ACKO.
2. Simultaneous drive and sense signals, i.e., ACTN and
3. Drive or sense signals, i.e., IRE, IRD, IRC and COLN.
The first set of signals are either used as point to point
links, or with external arbitration logic. In both cases the
load on these signals will not be large, so the on-chip driv-
ers are adequate. This may not be true for signal classes
(2) and (3).
The Inter-RIC bus has been designed to connect RIC2As
together directly, or via external bus transceivers. The latter
is advantageous in large repeaters. In the second applica-
tion the backplane is often heavily loaded and is beyond
ANYXN. (Potentially these signals may be driven by mul-
tiple devices).
(Only one device asserts these signals at any instance in
time).
Note: DE = Bus Drive Enable active high, /RE = Bus Receive Enable active low
Note: The Inter-RIC bus is configured to use active low signals.
Figure 10. External Bus Transceiver Connection Diagram
(Continued)
Figure 11. Mode Load Operation
27
the drive capabilities of the on-chip bus drivers. The need
for simultaneous sense and drive capabilities on the ACTN
and ANYXN signals, and the desire to allow operation with
external bus transceivers, makes it necessary for these bus
signals to each have a pair of pins on the RIC2A. One
drives the bus, the other senses the bus signal. When
external bus transceivers are used, they must be open col-
lector / open drain to allow wire-ORing of the signals. Addi-
tionally, the drive and sense enables of the bus transceiver
should be tied in the active state.
The uni-directional nature of information transfer on the
IRE, IRD, IRC and COLN signals, means a RIC2A is either
driving these signals or receiving them from the bus, but
not both at the same time.
input / output pin is adequate for each of these signals. If
an external bus transceiver is used with these signals the
Packet Enable "PKEN" RIC2A output pin performs the
function of a drive enable and sense disable.
Figure 10 shows the RIC2A connected to the Inter-RIC bus
via external bus transceivers, such as National's DS3893A
bus transceivers.
Thus a single bi-directional
www.national.com