EDE300 View Datasheet(PDF) - Unspecified

Part Name

Description

Manufacturer

EDE300

Parallel/ Serial Transceiver IC

Unspecified 

Notice that the MAX233 (or MAX232) voltage level shifter is needed for connection to a PC to meet

the required RS-232 line voltage requirements. A level shifter, as is used in the above two examples,

is not needed for connection to a Stamp or microcontroller, as can be seen in the 'BASIC STAMP

CONNECTION' section, or between two EDE300's, as illustrated below.

Figure Three: Two-Wire/ Wireless Data Transmission

This arrangement is useful when 8-bit data needs to be sent in one direction across a twisted

pair or coaxial cable. A variation on this schematic is the addition of a RF transmitter/ receiver pair

on the data line, providing a wireless 8-bit connection. For example, with the TX-99 and RE-99

transmitter/ receiver pair from Ming Microsystems (available from Digi-Key, 1-800-DIGI-KEY), an 8-

bit wireless bus can be implemented. Serial data from the transmitting EDE300 is fed into the TX-99.

The RE-99 receives the serial data and feeds it to the receiving EDE300. Alternately, short range

transmission could be accomplished via an infrared transmitter/ receiver pair.

HOST CONTROL MODE

In Host Control Mode, selected by wiring the Mode (Pin 3) high, the EDE300 takes data-flow

instructions from a host device connected to it serially instead of from the Data Direction Pin (Pin 1).

The host, typically a PC, STAMP, or microcontroller, sends a one-byte command to the EDE300

instructing it to either receive one data byte and latch it onto the data pins (D0..D7) or to read the

data pins and transmit this value serially.

The host should transmit a value of either "1" or "2" to the EDE300 in Host Control Mode. If

an ASCII '1' is received (00110001b), the EDE300 will wait for one byte of data to be transmitted

serially from the host and will then latch this data onto its data pins. The Dir/ Latch (Pin 1) pin will

be held high. If an ASCII '2' is received (00110010b), the EDE300 will read its data pins and

transmit this value serially back to the host. The Dir/ Latch (Pin 1) pin will be held low. This

unidirectional Host Control Mode is convenient when too much data would be transmitted using

Local Control Mode. Note that the ASCII characters "1" and "2" must be used, instead of the values

one and two. This enables the EDE300 to be used with a terminal program as well.

Host Control Mode, however, is most useful when implemented as a bi-directional interface.

COPYRIGHT © 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 4

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