EDE300 Parallel/ Serial Transceiver IC
EDE300
Dir/Latch
XMIT
18
Serial Transmit
0=2400,1=9600 2
BAUD
RCV
17
Serial Receive
0=Local, 1=Host 3
Mode
OSC1
16
Oscillator Connection
+5V
OSC2
15
Oscillator Connection
+5V
14
Connect to +5V DC
Data Direction, Output Latch 1
Connect to +5V DC 4
Digital Ground
5
GND
Data I/O Pin 0
6
D0
D7
13
Data I/O Pin 7
Data I/O Pin 1
7
D1
D6
12
Data I/O Pin 6
Data I/O Pin 2
8
D2
D5
11
Data I/O Pin 5
Data I/O Pin 3
9
D3
D4
10
Data I/O Pin 4
The EDE300 Parallel/ Serial Transceiver IC is a 5 volt, 18 pin package designed to
conveniently convert 8-bit parallel data into serial format and vice-versa. The EDE300 is ideal for
logging data to a PC, controlling hardware via the PC serial port, communicating 8-bit data via a
serial connection, and expanding I/O capabilities on microcontrollers and Stamps. The EDE300 is
BAUD-selectable, offering both 2400 and 9600 BAUD communication. PC connection requires the
use of a voltage level shifter such as the MAX233. The EDE300 can be configured as either a halfduplex transmitter, a half-duplex receiver, or a half-duplex bi-directional transceiver.
PIN DEFINITIONS
Flow Control Pins:
Data Direction, /Latch (PIN 1):
Baud Rate (PIN 2):
Mode (PIN 3):
Data Pins:
Serial Transmit (PIN 18) :
Serial Receive (PIN 17):
D0..D7 (PIN 6..PIN 13):
In Local Control Mode pin is an INPUT:
Input of 0 = Parallel to Serial, 1 = Serial to Parallel.
In Host Control Mode, pin is an OUTPUT:
EDE300 drives this pin low on receive, high on transmit
0 = 2400 BAUD, (N 8 1); 1 = 9600 BAUD, (N 8 1)
0 = Local Control Mode, 1 = Host Control Mode
Serial data is output from the EDE300 via this pin
Serial data is input to the EDE300 via this pin
Data I/O Pins (DO is least significant bit)
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 1
Clock/ Power Pins:
4 MHz Resonator Connection
Connect to +5 VDC
Connect to 0 VDC (GND)
OSC1,OSC2 (PIN 16,PIN 15):
Power (PIN 14,PIN 4):
Ground (PIN 5):
LOCAL CONTROL MODE
In Local Control Mode, enabled by wiring the Mode pin low (Pin 3), directional control is
selected by the condition of the Dir/Latch pin (Pin 1). When Local Control Mode is selected and the
Dir/Latch pin is low, the EDE300 acts as a Parallel to Serial transmitter, continually reading the 8 data
pins (D0..D7) and sending this value out the serial XMIT pin (Pin 18). When Local Control Mode is
selected and the Dir/Latch pin is high, the EDE300 acts as a Serial to Parallel receiver, continually
monitoring the RCV pin (Pin 17) and latching the received data onto the 8 data pins (D0..D7).
NOTE: Switching the Dir/Latch pin causes the data I/O pins (D0..D7) to switch from inputs to outputs
and vice-versa. Care should be taken that data is not input into the 8 data pins while the EDE300 is
in Serial to Parallel mode (Pin 17 high); otherwise damage may occur to the EDE300 or the external
circuitry as both attempt to drive the I/O pins. See the Host Control Mode section's schematics for
details on switching the data inputs and outputs with the EDE300. The following schematics depict
the EDE300 in a basic, unidirectional hookup, transmitting (Figure One) and receiving (Figure Two)
data to and from a PC via the PC serial port COM 1.
Figure One: Unidirectional Serial Transmission to PC
The following code, written in ‘Turbo C’, illustrates the reception of the EDE300’s data stream. It can
be used in conjunction with the hardware setup in Figure One.
#include <stdio.h>
char data;
main()
/* 8 BIT VARIABLE TO HOLD INCOMING DATA */
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 2
{
while(1)
/* BEGIN INFINITE LOOP */
{
data = inportb(0x3f8);
printf(“%d”,data);
if (data == 0) exit(0);
}
/* READ COM PORT #1 */
/* CAST ‘CHAR’ TO 'INT' TO VIEW ACTUAL VALUE */
/* IF INPUT IS ZERO, EXIT INFINITE LOOP */
}
NOTE: If your PC is not sending or receiving data properly in these examples, you may need to
enter the following at the command prompt:
MODE COM1 9600 N 8 1
This will set up the COM1 port correctly for use at 9600 BAUD as is used in the hardware examples
in this section.
Figure Two: Unidirectional Serial Reception from PC
The following code, written in ‘Turbo C’, illustrates a data write to the EDE300. It can be used in
conjunction with the hardware setup in Figure Two.
#include <stdio.h>
char data;
main()
{
data = 128;
outportb(0x3F8,data);
}
/* 8-BIT VARIABLE TO HOLD OUTGOING DATA */
/* VALUE TO BE WRITTEN TO EDE300 */
/* WRITE 'DATA' TO COM PORT #1 */
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 3
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 8bit 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
Making use of the Dir/ Latch pin, the EDE300 can simultaneously latch data from a PC/ Stamp and
transmit data to the PC/ Stamp. The host PC/ Stamp would simply send a "1" command followed by
an output data byte, and then send a "2" command to tell the EDE300 to transmit data back. This
arrangement is shown in Figure Four below. The Dir/ Latch pin causes a data receive request to be
latched onto the '373, and a data transmit request to read from the '245. Note: use of the '245 may
in some circumstances cause brief glitches on the '373 outputs. We recommend this arrangement
only for output devices in which a small (0 to 25 ns) output glitch would be acceptable (eg. LED's,
relay control, etc.).
Figure Four: Simultaneous Bi-directional Host-Control Mode Arrangement
The following code, written in 'Turbo C', illustrates one method for using the EDE300 in bidirectional mode:
#include <stdio.h>
char value;
send (char x)
{
while ((inportb(0x3FD) & 0x20) == 0);
outportb(0x3F8,0x31);
while ((inportb(0x3FD) & 0x20) == 0);
outportb(0x3F8,x);
}
/* main loop data variable */
/* write 'x' to EDE300 */
/*
/*
/*
/*
hold until transmitter is ready */
select 'receive byte' on EDE300 */
hold until transmitter is ready */
write 'x' to EDE300 */
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 5
char receive()
{
char value;
value = inportb(0x3F8);
while ((inportb(0x3FD) & 0x20) == 0);
outportb(0x3F8,0x32);
while ((inportb(0x3FD) & 0x01) == 0);
value = inportb(0x3F8);
return (value);
}
/* receive one byte from EDE300 */
main()
{
bioscom (0,0xE0|0x03,0);
/* main program loop */
/*
/*
/*
/*
/*
/*
stores incoming byte */
flush input buffer */
hold until transmitter is ready */
select 'send byte' on EDE300 */
hold until a byte is received */
receive byte from EDE300 */
/* set 9600 BAUD, 8 bit data */
do
{
value = receive();
send (value);
}
while (value != 0);
}
/* read byte from EDE300 into 'value' */
/* write 'value' back to EDE300 */
/* exit if 'value' = 0 */
This program reads one byte from the '245 via the EDE300 and writes the same value back
to the '373 via the EDE300. This is a very simple example - it is intended only to illustrate the proper
use of the EDE300's Host Control Mode. Notice that the subroutine 'receive()' returns one byte of
data from the EDE300, and the subroutine 'send(value)' transmits the byte stored in value to the
EDE300. In this example, the BAUD rate does not need to be set from the command prompt; it is set
to 9600 BAUD in software.
BASIC STAMP CONNECTION
The EDE300 can make a very effective I/O expander for the BASIC Stamp™ or other
microcontroller devices capable of transmitting and receiving serial data. In order to keep from
overrunning the Stamp with data from the EDE300, it is recommended that the EDE300 be used in
Host Control Mode when used with the Stamp, whether you are performing unidirectional input,
unidirectional output, or half-duplex bi-directional I/O. This way, the host (Stamp) controls when it
will receive a byte and when it will transmit a byte.
Bi-Directional Communication with BASIC Stamp™ I
To use the EDE300 with the BASIC Stamp™ in a bi-directional arrangement, refer to the
schematic in Figure Four, above. As the EDE300 can communicate with a Stamp using standard
+5V signals, no voltage level converter (MAX233) is needed for the connection. Simply remove it
from the schematic shown in Figure Three, and wire in the Stamp as follows:
Stamp Pin 7 <-------> EDE300 Pin 17 (Serial Receive)
Stamp Pin 6 <-------> EDE300 Pin 18 (Serial Transmit)
Then connect the EDE300's BAUD Pin (Pin 2) to GND instead of +5V as is shown in the example
for connection to a PC in Figure Four. This will tell the EDE300 to communicate at 2400 BAUD
instead of 9600. Also, you will need to connect the Stamp's ground pin to the EDE300's ground pin.
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 6
Once connected, the following example code, running on the Stamp, illustrates the simple example
of polling the '245's eight inputs and writing this value back to the '373's latched outputs.
pause 200
loop: serout 7,T2400, ("2")
serin 6,T2400,b2
serout 7,T2400,("1")
serout 7,T2400,(b2)
if b2 <> 0 then loop
'
'
'
'
'
'
pause Stamp while all circuitry powers up
send the character "2" out pin 7 at 2400 BAUD
read serial byte send back from EDE300, store in b2
tell EDE300 to accept next byte of data
send value in b2 to EDE300 to be latched onto output of '373 IC
continue until input byte = 0
If, however, you simply wish to use the EDE300 for unidirectional communication with a
Stamp (to expand the I/O capabilities of the Stamp), you would not need the '245 or '373 IC's. The
EDE300's eight data pins would serve as the eight input pins in unidirectional input mode, or as the
eight output pins in unidirectional output mode.
NOTE: In the following two arrangements, the EDE300 is being used in Host Control Mode, which
means that its Data Direction/Latch Pin (Pin 1) is made an output rather than an input (as it is in Local
Control Mode). In the following two examples leave this pin unconnected; data flow direction is
determined by the host. The Data Direction/Latch Pin (Pin 1) should NEVER be driven while the
EDE300 is in Host Control Mode.
Unidirectional Communication with BASIC Stamp™ I - Output Only
The following schematic will make eight digital outputs from one Stamp I/O pin.
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 7
The following code, written for the BASIC Stamp™ I, when used with the above schematic,
will loop from zero to ten, writing the appropriate binary value to the Output Port of the EDE300
each time, stopping with the binary value 00001010b latched onto the EDE300's data I/O port.
pause 200
for b2 = 0 to 10
serout 7,T2400,("1")
serout 7,T2400,(b2)
next b2
' pause Stamp while EDE300 powers up
' tell EDE300 to accept next byte of data
' send value in b2 to EDE300 to be latched
' repeat loop until b2 = ten
Unidirectional Communication with BASIC Stamp™ I - Input Only
The following schematic will make eight inputs from two Stamp pins. Notice that in the
previous example only one pin was required; in this example, however, we still need to maintain a
serial output pin on the stamp to tell the EDE300 to send data, as well as a serial input pin on the
Stamp to receive that data.
The following code, written for the BASIC Stamp™ I, when used with the above schematic, will read
the value on the EDE300's I/O port and return it to the PC programming the Stamp via a debug
window.
pause 200
serout 7,T2400,("2")
serin 6,T2400,b2
debug b2
'
'
'
'
pause Stamp while EDE300 powers up
tell EDE300 to read its I/O port and transmit the value
read transmitted value into b2
return value in b2 to Stamp's programming PC via debug window
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 8
ABSOLUTE MAXIMUM RATINGS
Oscillator frequency ......................................... 4 MHz
Supply Voltage ................................................. 7.5V
Ambient temperature under bias ...................... -40°C to +125°C
Max. current sinked by output pin .................... 25mA
Max. current sourced by output pin .................. 25mA
Max. current sourced by all 8 data pins.............. 200mA
Max. current sinked by all 8 data pins................ 200mA
STANDARD OPERATING CONDITIONS
Supply voltage ................................................. 3.0V to 5.5V
Operating temperature ..................................... 0°C to +70°C
The EDE300 IC is implemented as firmware on a PIC16C554 microcontroller, manufactured by Microchip Technology, Inc.
For a more comprehensive technical summary of this device, please refer to the PIC16C554 datasheet (available from the ELab web site).
IMPORTANT NOTICE
E-LAB Digital Engineering, Inc. (E-LAB), reserves the right
to change products or specifications without notice.
Customers are advised to obtain the latest versions of
product specifications, which should be considered
when evaluating a product’s appropriateness for a
particular use.
THIS PRODUCT IS WARRANTED TO COMPLY WITH
E-LAB’S SPECIFICATION SHEET AT THE TIME OF
DELIVERY. BY USING THIS PRODUCT, CUSTOMER
AGREES THAT IN NO EVENT SHALL E-LAB BE LIABLE
FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL
OR CONSEQUENTIAL DAMAGES AS A RESULT OF
THE PERFORMANCE, OR FAILURE TO PERFORM, OF
THIS PRODUCT.
E-LAB MAKES NO OTHER WARRANTIES, EXPRESSED
OR
IMPLIED,
INCLUDING
ANY
IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE.
E-LAB’s LIABILITY IS FOR A PERIOD NO GREATER
THAN 90 DAYS FROM DATE OF SHIPMENT BY E-LAB
AND IS LIMITED TO REPLACEMENT OF DEFECTIVE
PRODUCT. This warranty covers only defects arising
under normal use and not malfunctions resulting from
misuse, abuse, modification, or repairs by anyone other
than E-LAB.
E-LAB’S PRODUCTS ARE NOT AUTHORIZED FOR USE
AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS
WRITTEN APPROVAL OF THE PRESIDENT OF E-LAB.
Life support devices or systems are those which are
intended to support or sustain life and whose failure to
perform can be reasonably expected to result in a
significant injury or death to the user.
Critical
components are those whose failure to perform can be
reasonably expected to cause failure of a life support
device or system or affect its safety or effectiveness.
COPYRIGHT NOTICE
This product may not be duplicated. E-LAB Digital Engineering, Inc. holds all copyrights on firmware, with all rights
reserved. Unauthorized duplication of this device may be subject to penalty under state and/ or federal law.
EDE300 and the E-LAB logo are trademarks of E-LAB Digital Engineering, Inc. All other trademarks and registered
trademarks are property of their respective owners.
CONTACTING US
We are continually updating our product line. Please contact us for our latest product information.
E-LAB Digital Engineering, Inc.
1600 N. 291 Hwy. Ste. 330
P.O. Box 520436
Independence, MO 64052-0436
Telephone: (816) 257-9954
FAX: (816) 257-9945
Internet:
www.elabinc.com
E-Mail: [email protected]
COPYRIGHT 1996 E-Lab Digital Engineering, Inc. All Rights Reserved. Page # 9