mc68160b Freescale Semiconductor, Inc, mc68160b Datasheet - Page 5

• Manufacturer Part Number: mc68160b
• Description: Enhanced Ethernet Transceiver
• Manufacturer: Freescale Semiconductor, Inc

OSCILLATOR AND FREQUENCY MULTIPLIER
MODE SELECT
MOTOROLA ANALOG IC DEVICE DATA
Pin(s)
12
16
17
27
28
29
46
3
4
5
6
9
TPFULDL
TPSQEL
TPAPCE
Symbol
APORT
MFILT
LOOP
TPEN
CS0
CS1
CS2
X1
X2
(TTL/CMOS)
CMOS
CMOS
Type
O/C
TTL
TTL
TTL
TTL
TTL
TTL
TTL
I/C
I/O
C
I
I
I
I
I
I
Table 1. Pin Function Description (continued)
Frequency Multiplier Filter Connection Point: An external resistor capacitor filter must be
attached to this pin.
Oscillator Inverter Input and Crystal Connection Point: When connected for crystal
oscillator operation, the frequency of the clock which appears at TCLK is half that of the
crystal oscillator. As an option, instead of connecting to a crystal, X1 may be driven from an
external 20 MHz CMOS compatible clock generator.
Oscillator Inverter Output and Crystal Connection Point: This pin is used only for the
connection of an external crystal and capacitor. It must be left unconnected if X1 is driven by
an external CMOS Clock generator.
Mode Select: The logic states applied to these pins select the appropriate interface for the
desired IEEE–802.3 controller or enable the standby mode. When the standby mode is
selected, the MC68160B power supply current is greatly reduced. Additionally, in the standby
mode, all of the controller inputs and outputs are driven to the high impedance state.
Diagnostic Loopback: Asserting this function causes serial NRZ data at the TX input to be
Manchester encoded and then looped back through the Manchester decoder, appearing at
the RX output. This diagnostic loopback function operates independent of Twisted Pair (TP)
or Access Unit Interface (AUI) port connectivity or activity. Neither the TP port nor the AUI
port transmits data from the controller while diagnostic loopback is selected. Likewise, the
controller interface receives data neither from the TP nor the AUI receivers while in this
mode. The polarity fault detection and link integrity functions are not inhibited by the
diagnostic loopback mode. If otherwise enabled, they continue to function. If the twisted pair
port is selected, and TPSQEL is driven to the low logic state, a collision detect pulse is
delivered following each transmission to simulate the twisted pair SQE test.
Automatic Port Selection Enable: When high, MC68160B will automatically select the TP
or AUI port based on the presence or absence of valid link beats or frames at the TP receive
input. If the AUI port is automatically selected, the MC68160B will continue to produce link
pulses for the TP port. Changing ports requires approximately 1.0 ms to allow the circuitry for
the new port to resume normal operation. The power consumption is minimized in the
circuitry associated with the unselected port.
Twisted Pair Signal Quality Error Test Enable: Forcing this pin low enables testing of the
internal TP collision detect circuitry after each transmit operation to the TP media. This
function provides a simulated collision to as much of the MC68160B collision detect circuitry
as possible without affecting the attached twisted pair channel. A normal SQE test results in
a high logic state at the CLSN controller interface pin which begins 6 to 16–bit times after the
last transition of a transmitted signal and continues for 5 to 15–bit times. (When the AUI port
is selected, SQE test signals are generated by the coaxial cable transceiver and delivered to
the controller via the MC68160B ACX+/– receive inputs)
Twisted Pair Full Duplex Mode Select: Forcing this pin low allows simultaneous transmit
and receive operation on the twisted pair port without an indicated collision. This pin is not to
be asserted with LOOP as a test mode is enabled that disrupts normal operation.
Twisted Pair Automatic Polarity Correction Enable: When TPAPCE is high, automatic
polarity correction is enabled, and MC68160B will internally correct for a polarity fault on the
receive circuit. Additionally, when TPAPCE is high, the presence of a polarity fault is
indicated on TPPLR.
Twisted Pair Port Enable: If APORT is low, TPEN is an input which determines whether the
AUI port (TPEN low) or TP port (TPEN high) will be manually selected. If the AUI port is
manually selected, the MC68160B will not produce link pulses for the TP port.
If APORT is high, TPEN is an output which will indicate which port has been automatically
selected by driving TPEN low (for AUI) or high (for TP). In its output mode TPEN can sink
10 mA in the low output state and source 10 mA in the high output state. (See Pin 9
Description.)
Changing ports requires approximately 1.0 ms to allow the circuitry for the new port to
resume normal operation. The power consumption is minimized in the circuitry associated
with the unselected port. In the standby mode, this pin is driven to the high impedance state.
MC68160B
Name/Function
5