78Q2120
10/100BASE-TX
Ethernet Transceiver
CONTROL AND STATUS
(continued)
8
PIN
64-PIN
80-PIN
TYPE
DESCRIPTION
ANEGA
47
56
I
AUTO-NEGOTIATION ABILITY: Strapped to logic high to allow auto-
negotiation function. When strapped to logic low, auto-negotiation
logic is disabled and manual technology selection is done through
TECH[2:0]. This pin is reflected as ANEGA bit (MR1.3).
TECHNOLOGY ABILITY/SELECT: TECH[2:0] sets the technology ability of the
chip which is reflected in MR0.13,8 MR1.14:11 and MR4.12:5.
TECH[2:0]
Technology ability
000
Advertise no technology capability; however,
parallel detect from the link partner will
establish the link speed.
111
Both 10BASE-T and 100BASE-TX,
Both half and full duplex
001
10BASE-T, half duplex
010
100BASE-TX, half duplex
011
Both 10BASE-T and 100BASE-TX,half duplex
100
None
101
10BASE-T Both half and full duplex
110
100BASE-TX Both half and full duplex
TECH[2:0]
44-46
53-55
I
RPTR
50
61
I
REPEATER MODE: When pulled high, this pin puts the chip into repeater
mode. In this mode, full duplex is prohibited, CRS responds to receive
activity only and, in 10BASE-T mode, the SQE test function is disabled. This
mode can also be entered with MR16.15.
MDI (MEDIA DEPENDENT INTERFACE)
TXOP,
TXON
61, 62
77,78
A
TRANSMIT OUTPUT POSITIVE/NEGATIVE: Transmitter outputs for
both 10BASE-T and 100BASE-TX.
RXIP,
RXIN
52, 51
64,63
A
RECEIVE INPUT POSITIVE/NEGATIVE: Receiver inputs for both
10BASE-T and 100BASE-TX.
LED INDICATORS
The LED pins use standard logic drivers. They output a logic low when the LED is meant to be on and a logic high when it is
meant to be off. The LED should be connected in series with a resistor between the output pin and the power supply.
LEDL
LEDTX
40
39
48
47
O
O
LED LINK: ON for link up.
LED TRANSMIT: ON when there is a transmission (normally OFF).
LEDRX
38
46
O
LED RECEIVE: ON when there is a reception (normally OFF).
LEDCOL
37
45
O
LED COLLISION: In half duplex mode, this is a collision indicator and turns-
ON when a collision occurs. In full duplex mode, this LED is held OFF.
LEDBTX
36
44
O
LED 100BASE-TX: ON for 100BASE-TX connection and OFF for
other connections.
LEDBTX
is OFF during auto-negotiation.
LED 10BASE-T: ON for 10BASE-T connection and OFF for other
connections.
LEDBT
is OFF during auto-negotiation.
LED FULL DUPLEX: ON when in full duplex mode and OFF when in
half duplex mode.
LEDBT
48
57
O
LEDFDX
49
58
O