COM20022 Ver la hoja de datos (PDF) - SMSC -> Microchip

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COM20022

10Mbps ARCNET controller with 2Kx8 on-board RAM

SMSC -> Microchip 

PIN NO

NAME

35

DMA Ack

38

Terminal

Count

40

Refresh

Execution

24

nPulse 1

25

nPulse 2

28

Receive In

29

nTransmit

Enable

21

Crystal

22

Oscillator

8,20,

32,43

6,11,

18,23,

30,41

19,27

Power

Supply

Ground

N/C

SYMBOL I/O

DESCRIPTION

nDACK

IN DMA Acknowledge signal. Active Low. When

BUSTMG is High, this signal is connected to internal

pull-up registers

TC

IN Terminal Count signal. Active polarity is

programmable. Default is active high. When

BUSTMG is High, this signal is connected to the

internal pull-up resistor.

nREFEX

IN Refresh execution signal. Falling edge detection.

This signal is connected to the internal pull-up

resistor.

TRANSMISSION MEDIA INTERFACE

nPULSE1 OUT In Normal Mode, these active low signals carry the

transmit data information, encoded in pulse format

as DIPULSE waveform. In Backplane Mode, the

nPULSE2 I/O nPULSE1 signal driver is programmable (push/pull

or open-drain), while the nPULSE2 signal provides a

clock with frequency of doubled data rate. nPULSE1

is connected to a weak internal pull-up resistor on

the open/drain driver in backplane mode.

RXIN

IN This signal carries the receive data information from

the line transceiver.

nTXEN

OUT Transmission Enable signal. Active polarity is

programmable through the nPULSE2 pin.

nPULSE2 floating before power-up;

nTXEN active low

nPULSE2 grounded before power-up;

nTXEN active high (this option is only available in

Back Plane mode)

XTAL1

IN An external crystal should be connected to these

XTAL2

OUT pins. Oscillation frequency range is from 10 MHz to

20 MHz. If an external TTL clock is used instead, it

must be connected to XTAL1 with a 390ohm pull-up

resistor, and XTAL2 should be left floating.

VDD

PWR +5 Volt power supply pins.

VSS

PWR Ground pins.

N/C

Non-connection

7

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