MB86960 Datasheet, PDF (39/65 Pages) Fujitsu Component Limited. – NETWORK INTERFACE CONTROLLER with ENCODER/DECODER (NICE)

MB86960
NICE
COL+
COL
RXDATA+
RXDATA
TXDATA+
TXDATA
0.1mF
240Ω
0.1mF
240Ω
0.1mF
0.1mF
1550
W
1550
W
1550
W
1550
W
ON-BOARD
MBL8392A
COAXIAL
TRANS–
CEIVER
270Ω _0.1mF
78Ω
270Ω
0.1mF
b. Simplified Termination for Coaxial Transceiver
NICE
COL+
COL
0.1mF
78Ω
0.1mF
RXDATA+
RXDATA
0.1mF
78Ω
0.1mF
ON-BOARD
MB86962
10BASE-T
TRANS–
CEIVER
TXDATA+
TXDATA
270Ω _0.1mF
78Ω
270Ω
0.1mF
c. Simplified Termination for on-board 10BASE-T Transceiver
Figure 12. Transceiver Interface Termination
Collision Signal Processing
As collisions are detected on the network media, the
external transceiver generates a 10 MHz signal on the
COL± differential inputs to the NICE’s encoder/decoder
section. When this signal is detected by NICE, it asserts
the internal collision line, and in some modes the COL
pin, pin 92, is also asserted.
The COL± differential driver inputs require termination
like that for the RXDATA± inputs. See Figures 11 and 12
for suggested cable termination.
Loopback
Loopback capability is provided to allow testing of NICE
without sending signals onto the LAN media. The
loopback function is invoked by clearing the LBC bit,
DLCR4<1>. Loopback operation is illustrated in Figure
13.
Data is routed from the transmit buffer through a FIFO to
the transmit section of the data link controller, through
the internal Manchester encoder, back through the
Manchester decoder, through the receiver section of the
data link controller, and is then stored in a receive buffer.
The test software can then read and check the received
packet which has traveled through nearly all transmit and
receive sections of the chip.
When an external encoder/decoder is used, the data is
output on TXD and received at RXD. The external
Manchester encoder/decoder should respond to assertion
of its LBC input by looping its transmitter output to its
receiver input internally, and should block the transmit
data from appearing at its network output pin. Fujitsu’s
MB86951 and MB502A Encoder/Decoders, and
MB86961 Encoder/Decoder with 10BASE-T Transceiv-
er, for example, all respond in this way.
TXD
*
LBC
*
RX
D*
NICE Internal
Encoder/Decod
er
NO SIGNALS
APPEAR AT
OUTPUT PINS
NICE Data Link Controller Section
* In “NICE” mode, these are internal signals
and no signals appear on the corresponding pins.
Figure 13. NICE in Loopback Mode