Remote Technologies RPC-320 User Manual

RPC-320 USER'S MANUAL REV 2

Copyright 1997, 1999 - Remote Processing Corporation.
All rights reserved. However, any part of this document
may be reproduced with Remote Processing cited as the
source.

The contents of this manual and the specifications her ein
may change without notice.

TRADEMARKS

RPBASIC-52™ is a trademark of Remote Processing
Corporation.

PC SmartLINK® is a trademark of Octagon Systems
Corporation.

BASIC-52© is a trademark of Intel Corporation.

NOTICE TO USER

The information contained in this manual is believed
correct. However, Remote Processing assumes no
responsibility for any of the circuits described herein,
conveys no license under any patent or other right, and
make no representations that the circuits are free from
patent infringement. Remote Processing makes no
representation or warr anty that such applications will be
suitable for the use specified without further testing or
modification. The user must make the final
determination as to fitness for a particular use.

Remote Processing Corporation' s general policy does not
recommend the use of its products in life support
applications where the failure or malfunction of a
component may directly threaten life or injury. It is a
Condition of Sale that the user of Remote Processing
products in life support applications assum es all the risk
of such use and indemnifies Remote Pr ocessing against
all damages.

Remote Processing Corporation
79 75 E. Harvard Ave.
Denver, Co 802 31 USA
Tel: (303) 690 - 1588
Fax: (303) 690 - 1875
w w w.rp3.com

P/N 1366
Revision: 2.8

Page i RPC-320

TABLE OF CONTENTS

SECTION 1 OVERVIEW

DESCRIPTION ................... 1-1

MANUAL ORGANIZATION .......... 1-1

MANUAL CONVENTIONS ........... 1-1

Symbols and Terminology ......... 1-2

TECHNICAL SUPPORT ............. 1-2

SECTION 2 SETUP AND OPERATION

INTRODUCTION ................. 2-1

OPERATING PRECAUTIONS ......... 2-1

EQUIPMENT .................... 2-1

FIRST TIME OPERATION ........... 2-2

Using a PC ................... 2-2

Using a Terminal ............... 2-2

UPLOADING AND DOWNLOADING

PROGRAMS ................. 2-2

Editing program s and pro gram ming hints 2-3

WHERE TO GO FROM HERE ......... 2-4

TROUBLESHOOTING .............. 2-4

SECTION 3 SAVING PROGRAMS

INTRODUCTION ................. 3-1

SAVING A PROGRAM ............. 3-1

AUTORUNNING .................. 3-2

PREVENTING AUTORUN ........... 3-2

LOADING A PROGRAM ............ 3-2

CHANGING EPROM SIZE ........... 3-2

ALTERNATE EPROMS ............. 3-3

COMMANDS .................... 3-3

SECTION 6 DIGITAL AND OPTO PORTS

INTRODUCTION ................. 6-1

DIGITAL I/O PORTS ............... 6-1

Digital Port J3 ................. 6-1

Digital Port P6 ................. 6-2

High Current Port L8 ............ 6-2

Optically Isolated Input ........... 6-2

Digital I/O Commands ............ 6-2

High Curr ent Output ............. 6-3

Interfacing Digital I/ O to an opto- module

rack ..................... 6-4

Interfacing to switches and other devices 6-4

Digital I/O program ming exa mple .... 6-4

Pulse Width Modulation (PWM) ...... 6-5

COMMANDS .................... 6-6

SECTION 7 CALENDAR/CLOCK

DESCRIPTION ................... 7-1

SETTING DATE AND TIME .......... 7-1

COMMANDS .................... 7-1

SECTION 8 DISPLAY PORT

INTRODUCTION ................. 8-1

CONNECTING DISPLAYS ........... 8-1

WRITING TO THE DISPLAY ......... 8-1

PROGRAMMING EXAMPLE ......... 8-1

DISPLAY TYPES ................. 8-2

DISPLAY CONNECTOR PIN OUT ..... 8-2

COMMANDS .................... 8-2

SECTION 4 SERIAL PORTS

DESCRIPTION ................... 4-1

COM0 SERIAL PORT .............. 4-1

COM1 SERIAL PORT .............. 4-1

RS-422/485 OPERATING INFORMATION . 4-2

RS-422/485 Termination network ..... 4-2

Two wire RS-485 ............... 4-3

Multidrop Network .............. 4-3

ACCESSING SERIAL BUFFERS ....... 4-3

ACCESSING COM0 AND COM1 ....... 4-4

DISABLING CON TROL -C ........... 4-4

SERIAL PORT PIN OUT ............ 4-4

SECTION 5 RAM MEMORY

INTRODUCTION ................. 5-1

CHANGING M EMORY ............. 5-1

BATTERY BACKUP ............... 5-1

Checking the battery ............. 5-1

RESERVED MEMORY ............. 5-2

STORING VARIABLES IN RAM ....... 5-2

BLOCK DATA TRANSFER ........... 5-3

ASSEMBLY LANGUAGE INTERFACE .. 5-3

COMMANDS .................... 5-3

SECTION 9 KEYPAD PORT

INTRODUCTION ................. 9-1

PROGRAMMING EXAMPLE ......... 9-1

KEYPAD P ORT P IN OU T - J5 ......... 9-2

SECTION 10 ANALOG INPUT

DESCRIPTION ................... 10-1

CONNECTING ANALOG INPUTS ...... 10-1

Overvoltage conditions ............ 10-1

Grounding .................... 10-1

INITIALIZATION ................. 10-1

Differential Mode ............... 10-2

Examples using CON FIG AIN ....... 10-2

Acquiring Analog Data .............. 10-2

Noise Notes ................... 10-3

Temperature Measurement ......... 10-3

Data logging on a timer tick ........ 10-4

MEASURING HIGHER VOLTAGES .... 10-4

CONVERTING ANALOG MEASUREMENTS 10-4

Measuring 4-20 mA current loops ..... 10-4

AMPLIFIERS .................... 10-5

CALIBRATION .................. 10-5

COMMANDS .................... 10-5

Page ii RPC-320

TABLE OF CONTENTS

SECTION 11 WATCHDOG TIMER

DESCRIPTION ................... 11-1

EXTERNAL RESET ................ 11-1

DESCRIPTION ................... 11-1

OPTICALLY ISOLATED INTERRUPT ... 11-1

INTERRUPT CHARACTERISTICS ...... 11-1

SECTION 12 EXTERNAL INTERRUPT

DESCRIPTION ................... 12-1

PROGRAMMING ................. 12-1

Program examples .............. 12-1

COMMANDS .................... 12-2

SECTION 13 MULTI-MODE COUNTER

DESCRIPTION ................... 13-1

SECTION 14 POWER REDUCTION

FURTHER POWER REDUCTION ...... 14-1

Program Exam ple ............... 14-2

SECTION 15 TECHNICAL INFORMATION

ELECTRICAL SPECIFICATIONS ...... 15-1

MEMORY AND I/O BANK MAP ....... 15-2

MECHANICAL SPECIFICATIONS ..... 15-2

JUMPER DESCRIPTIONS ........... 15-2

Page iii RPC-320

SOFTWARE REVISION HISTORY

V1.04 Release for RPC320

V1.05 BSAVE returned a hardware er ror when ver ify

was bad. In fact, save was OK.

V1.06 LCD graphics hardware CS and reset are

reversed. Compensated in software.

V1.07 MTOP was useless in any system, especially a

32K RAM.

V1.08 Variables E and F would get dropped if

followed by a space.
Added delays between data strob e writes to
LCD display.

V1.09 STR(7, . . .) did not put in a CR into the put

string, causing longer strings to be printed.

V1.10 Initial release for RPC-330.

Added AOT command (330 only)
Added COUNT, ON COM, ON COUNT, ON
LINE, and ON KEYPAD

V1.11 11/29/95

Added day of week to DAT E comm and and
function.

V1.12 12/01/95

Added code to use Atmel 29C040A flash.

V1.13 01/12/96

Added code to support IEE centry series
display (3602-100-05420)
Includes PRINT #port

V1.14 03/28/96

Fixed bug in ON COUNT. Returns error for
lines > 100.

V1.15 06/26/96

PEEK$ could cause BASIC to lock up under
right conditions.

V1.16 02/18/97

ON LIN E OF F could cause program to lock up
if running ON COM.
Syntax error when DISPLAY used with IF­THEN-ELSE.
Added PE EKF a nd POKE F com mands.

Page iv RPC-320

OVERVIEW SECTION 1

DESCRIPTION

The RP C-320 is a n embed ded contr oller with a built in
Basic language. Several features make it suitable as a
stand alone unit:

Built in RPBASIC-52 programm ing language
supports hardware using single commands. On card
flash EPROM programm er can save up to 8
programs to 62K , or about 500K tota l.

High speed multimode counter accepts quadrature or

single inputs. Programmable for up/dow n, binary,
divide-by-N, X1, X2 or X4 quadr ature counting.

LCD charac ter and gr aphic display and keypad ports

for operator interface.

Two R S-232 ser ial ports, one of whic h is

configurable for RS-422/485.

Watchdog timer resets card if a program "crashes".

34 digital I/O lines, 9 of which are high current

outputs. 24 of these lines can connect to an opto
rack or other TTL devices.

Eight channel, 12 bit resolution analog to digital

converter. Configurable operational amplifiers
allow you to signal condition inputs or measure
temperature.

from your PC are downloaded using a serial
communication program.

MANUAL ORGANIZATION

This manual provides all the infor mation r equired to
install, configure, and operate the RPC-320. Using this
manual you will be able to:

Interface the RPC-320 to your IBM compatible PC
or terminal.

Understand the operation of the RPC-320 hardware
using RPBASIC-52 programming software.

This manual assumes you are familiar with some type of
BASIC programming software. The syntax used by
RPBASIC-52 is similar to BASIC-52. If you are not
experienced with any BASIC softwar e, y ou may w ant to
refer to books and training programs available through
your local book store. The BASIC-52 Programming
Manual has information and examples for the original
commands. Comm ands unique or modified by
RPBASIC-52 are in the Software Supplement in this
manual.

Each chapter or section is written to first provide an
overview. Then, m ore specific information is provided.
Each chapter has some examples using Basic. A
summary of related hardware commands is at the end of
most chapters.

32K, 128K, or 512K RAM battery backable to save

process variables and other data when power is off.

32K or 512K flash EPROM to save program s and
data.

The RPC -320 uses an 80C320 CPU operating at 22.1184
Mhz. It can operate stand alone or on a network using
the RS-485 port. Its 4.7" x 7.0" size with 4 mounting
holes makes it easy to mount in a NEMA box.
Compactness is enhanced by on-board analog and digital
terminal strips.

RPBASIC-52 programming language is standard. T his
language is a version of the original Intel BASIC-52. It
was modified for the RPC -320 for c ontrol, data
acquisition applications, and on board hardware features.

Program development can take place on your PC, using
your word processor, or on the RPC-320. Programs

Page 1-1 RPC-320

MANUAL CONVENTIONS

Information appearing on your screen is shown in a
different type.

Example:

RPBASIC-52 V1.0
Copyright Intel (1985) and Remote Processing
Bytes free: 27434

OVERVIEW SECTION 1

TECHNICAL SUPPORT

Symbols and Term inology

If you have a question about the RPC-320 or RPBASIC-

NOTE: Text under this heading is helpful information.

It is intended to act as a reminder of some
operation or interaction with another device that
may not be obvious.

WARNING:

Information under this heading warns you of
situations which might cause catastrophic or
irreversible damage.

52 and can' t find it in this manual, call us and ask for
technical support. Technic al support hours ar e 9 AM to
4 PM mountain time.

When you call, please have your RPC-320 and BASIC-
52 PROGRAMMING MANUAL ready. Many times it is
helpful to know what the RPC-320 is used for, so please
be ready to describe its application as well as the
problem.

W[-] Denotes jumper block pins.

< xxx> Paired angle brackets are used to indicate a

specific key on your keyboard. F or exam ple
< esc> means the escape key.

BASIC uses the decimal convention for designating
addresses and data. There are times when hexadecimal
notation is more convenient to use. Notation use d in this
manual and BASIC-52 is the ' H' character after the
number. 8CH stands for 8C hexadecimal.

Phone: [phone]
FAX: [phone]

The RPC -320 uses a Dallas Semiconductor DS80C320
processor. Additional information can be obtained from
Dallas Semiconductor (214-450-0448, F AX 214-450

0470), or your distributor.

Page 1-2 RPC-320

OVERVIEW SECTION 1

Figure 1-1 System layout

Page 1-3 RPC-320

SETUP AND OPERATION SECTION 2

INTRODUCTION

The RPC -320 is ready to program as soon as you
connect it to a ter minal or PC a nd apply pow er. This
chapter describes what is needed to get a sign- on
message and begin programming.

Requirements for uploading and downloading programs
are discussed. A "W here to go from here" section tells
you what chapters to refer to in order to use the various
capabilities of the RPC-320. Finally, a troubleshooting
section helps out on the most common problems.

OPERATING PRECAUTIONS

The RPC -320 is designed to handle a wide variety of
temperature ranges at low power. These characteristics
require using CM OS components. CM OS is static
sensitive. To avoid damaging these components,
observe the following precautions before handling the
RPC-320.

1. Ground yourself before handling the RPC -320
or plugging in cables. Static electricity

can easily arc through cables and to the card.
Simply touching your PC before you touch the
card can greatly reduce the amount of static.

2. Do not insert or remove components when
power is applied. While the ca rd is a + 5 volt
only system, other voltages generated on the
card which affect other components.

EQUIPMENT

You will need the following equipment to begin using the
RPC-320:

RPC-320 embedded controller
PC with a serial port and com munications
program

or a

Terminal
VTC -9F ser ial cable
+ 5, 2 00 ma po wer su pply

Refer to Chapter 4, SERIAL PORTS, for wiring
information to make your own serial cable.

Figure 2-1 Connector location and function

Page 2-1 RPC-320

SETUP AND OPERATION SECTION 2

FIRST TIME OPERATION

Become familiar with the locations of connectors before
getting started. See Figure 2-1.

RPC -320 jump ers have been set at the fa ctory to op erate
the system immediately. For first time operation, do not
install any connectors or parts unless specified below.
Jumpers should be kept in default positions.

1. Connect power.

The RPC-320 needs + 5 ±0.25 volts at 100 ma.
Any well regulated supply that supplies this will
work. Be careful when using "switching" power
supplies. Some of the se supplies do no t regulate
properly unless they are adequately loaded. Don' t
forget that power requirements increase w hen opto
modules are used. G4 opto modules require up to
20 ma each.

Make sure pow er is off. Connect the power supply
to one of the appropriately marked terminals on the
RPC-320. There two power connectors: P2 and P6.
Either one may be used to connect power.

2. Hook up to a PC or terminal.

Turn on your power supply. On power up a
copyright message is printed.

RPBASIC-52 V1.09
RPC-320
Copyright Remote Processing (1994)
Bytes free: 63740

65,536 bytes of additional expanded memory detected
512K byte EPROM installed

If a nonsense message appears, your terminal or PC
may not be set to the appropriate communication
parameters. If the system still does not respond,
refer to TROUBLESHOOTING later in this chapter.

The sign on message may differ based on the RAM
and flash EPROM installed.

4. Testing.

The system is now in the " imme diate mode" and is
ready for you to start programming. T ype the
following program:

10 FOR X=0 TO 2
20 PRINT "Hello ",
30 NEXT
40 PRINT

You can use either a PC or CRT term inal to
program the RPC-320. Connect one end of the
VTC-9F connector to the 10 pin COM0 port on the
RPC-320. Refer to Figure 2-1 for connector
location.

Using a PC

Connect the VTC-9F serial cable to the PC's COM1
or COM 2 port. Y ou may need a 9 pin male to 25
pin female adapter. The VTC-9F is designed to
plug directly into the 9 pin serial port connector on a
PC.

Start up your serial communication program. Set
comm unication par ameter s to 9600 baud, 8 data

bits, no parity, 1 stop.

Using a Terminal

Follow your terminal instructions to set the baud
rate to 9600 baud, 8 data bits, no parity, and 1 stop.
You may need a 9 pin male to 25 pin male adapter
to connect the VTC-9F.

3. Power up.

Now type RUN. The system will display:

Hello Hello Hello

READY
>

Terminate a program by typing a < Ctrl> -C.

UPLOADING AND DOWNLOADING
PROGRAMS

Downloading program s means transferring them fr om
your PC (or terminal) to the RPC-320. Uploading
means transferring them from the RPC -320 back to the
PC. This section explains how to do both of these
procedures using generalized instructions for terminal
programs (Procomm , Windows Ter minal, etc.)

When uploading or downloading files, select ASCII text
format. XMODEM, YMODEM, or other formats are
not used.

RPBASIC-52 does not know when you are typing in a
program or if something else (laptop or mainfr ame) is

Page 2-2 RPC-320

SETUP AND OPERATION SECTION 2

sending it char acters. The upload and download file
does not contain any special codes; they are sim ply
ASCII characters.

Uploading programs is simply a process of receiving an
ASCII file. You or your program simply need to send
"LIST" to receive the entire program . The default baud
rate (9600) is rather high. The RP C-320' s baud rate is
changed using the CONFIG BAUD command.

Downloading a program requires transmitting an ASCII
file. As you type in (or download) a line, RPBASIC-52
tokenizes, or com piles, that line. The time to do this
depends upon its complexity and how many lines of code
have been entered.

RPBASIC-52 m ust finish compiling a line before starting
the next one. When a line is compiled, a "> " character
is sent. This should be your terminal programs pacing
character for downloading.

If your communications program cannot look for a
pacing prompt, set it to delay transmission after each line
is sent. A 100 ms delay is usually adequate, but your
program may be long and complex and require more
time. A r esult of a short transmission time is missing or
incomplete program lines.

increased download time.

Notice that you can write a program in lower case
characters. RPBASIC-52 translates them to upper case.

Some program mers put "N EW" as the first line in the
file. During debugging, it is common to insert
"temporary" lines. This ensures that these lines are
gone. Down loading time is increase d when the old
program is still pre sent. If you like to wr ite progr ams in
separate modules, you can download them separately.
Modules are assigned blocks of line numbers. Start up
code might be from 1 to 999. Interrupt handling
(keypad, serial ports) might be from lines 1000 to 1499.
Display output might be from 1500 to 2500. The
programmer must determine the number of lines
required for each section.

RPBASIC-52 automatically formats a line for minimum
code space. For example, you could download the
following line of code:

10 fora= 0to5

When you listed this line, it would appear as:

10 FOR A=0 TO 5

Editing programs and program ming hints

Files uploaded or downloaded are simply ASCII DOS
text files. No special characters or control codes are
used. You may create and edit programs using your
favorite word processor or editor. Just be sure to save

files in DOS text form at.

A technique used to further program documentation and
reduce code space is the use of comments in a
downloaded file. For example, you could have the
following in a file written on your editor:

REM Check position

REM Read output from the pot and
REM calculate the position

2200 a = ain(0) :REM Get position

The first 3 comments downloaded to the RPC -320
are ignored. Similarly, the empty lines between
comm ents are a lso ignored . L ine 2200, with its
comment, is a part of the program and could be listed.
The major pena lty by wr iting a progr am this w ay is

Spaces are displayed but not stored. The following line:

10 for a = 0 to 5

would be compressed and displayed as in the second
example above. Spaces are removed. However, spaces
as part of a remark or PRINT are not removed.

Instead of uploading and downloading programs, you can
save them to the on card EPROM. This is useful if you
are using a terminal to write program s. Simply type
SAVE. To retrieve a program, type LOAD.

Page 2-3 RPC-320

SETUP AND OPERATION SECTION 2

WHERE TO GO FROM HERE

If you want to do this: Turn to

Chapter

Save a program 3
Run a program at power up or

reset (autorun) 3
Know m ore abo ut serial por ts 4
Install a different RAM mem ory chip 5
Using RAM to save variables 5
Run an assembly language program 5
Configure digital I/O lines 6
Detect on/off switch status 6
Use high current outputs 6
Connect an external opto rack 6
Calendar/clock option 7
Connect Displays 8
Use a keypad 9
Measure voltages 10
Using inter rupts 12
Multi-mode counter 13
Use low power operation 14

attached, you should see a burst of activity. With a
volt meter, you should see a change in voltage.
Using a Fluke 8060A set to measure AC, you
should see a momentary reading above 2 volts.

3. Install the serial cable and make sure the voltages
and output activity are still there. Output is from
pin 3 on the VTC-9F. If not, check to make sure
something is not shorting the output.

4. Check the serial pa ram eters on y our P C or termin al.
They should be set to:

9600 baud, no parity, 8 data bits, 1 stop

5. If you are receiving a sign on me ssage but not ab le
to enter characters, check U8, pin 4 for at least -6
volts. When it is near 0 volts, the terminal or PC's
Tx line is not connected. When you pr ess a
character on the terminal or PC, you should see the
voltage go positive. Check the serial cable.
Transmitted signals from the PC or terminal are
from pin 5 on the 10 pin IDC connector.

Refer to the table of contents for a more detailed listing.

TROUBLESHOOTING

You would probably turn to this section because you
could not get the sign on message. If you are getting a
sign on message but can't enter characters, then read
section 5 below . T he following are tr oubleshooting hints
when you can' t get anything.

1. Check the power source. If it is below 4.65 volts at
the input power terminal, the RPC -320 will reset.
Power is 5 ±0.25 volts. Make sure it is a clean 5
volt source. If it dips intermittently to 4.65 volts
(due to switching noise or ripple), the card will reset
for about 100 ms. If the noise is frequent enough,
the card will be in permanent reset. Check U7, pin

8. If it is high (about 5 volts), then the car d is in
reset. This line should be low (about 0 volts).

2. Check the COM 0 port (J3). Rem ove the connector
from COM 0. R efer to the outline drawing earlier in
this chapter. Connect an oscilloscope (preferred) or
a voltmeter to pin 3 (Txd) and gr ound. Pin 3 should
be -6 volts or more negative. (Pin 1 is designated
by the v symbol on the connecto r. Pin 3 is next to
it, nearer the key opening.) If you have -6 volts or
more, press the reset switch. If you have a scope

If all of this fails, call technical support listed in chapter

1.

Page 2-4 RPC-320

SAVING PROGRAMS SECTION 3

INTRODUCTION

Program s are stored in an EPRO M in socket U6. You
can store one or more programs, depending upon
EPROM size. A BASIC program can call another when
a 512K byte EPROM is used.

Maximum program size that can be run at any one time
is about 62K, not including space for variables. 32K
bytes is the maximum program size when a 29C256 IC
type is used to save a program.

A conservative rule to determine program memory
requirements is one line requires 40 bytes. 32K bytes
would stor e 800 lines of code. Your application could
be significantly more or less, depending upon the
number of comm ands/line, com ments, and pr int
statements.

Despite the fact you may have a 128K or 512K RAM
installed, the maximum program size RPBASIC-52 can
run at one time is about 60K (including room for some
variable storage). The table below shows the maximum
capacity, maximum number of program lines, program
size at one time, and number of programs for an
EPROM type.

A flash EPROM is non-volatile (retaining data even
when power is disconnected), having an unlimited
number of read cycles and a limited number of write
cycles (about 1,000). A program is not run from
EPROM . It is transferred to RAM and run from there.
Programs in RAM can be m odified. They are saved to
EPROM for execution later.

The RPC -320 can autorun on power up or r eset by
removing jumper (W9). W hen autorun is on, the
program in EPROM segment 0 is loaded into RAM and
begins to execute immediately.

Figure 3-1 W3 autorun jumper

EPROM Max Prog Max No.
type Cap. lines Bytes Progs

29C256 30K 400 32K 1
29C040 509K 12400 62K 8

One program can call another using the EXECUTE n
command. n is from 0 to 7, depending upon the
EPROM type.

NOTE: When a program calls another, the old program

is completely replaced. All variables and
arrays are cleared (set to 0).

To keep variables, you m ust save them before calling the
new progr am. When the new program is running, these
variables are restored. Use PEEK and POKE to read
and save numbers and strings. See Chapter 5, STORING
VARIABLES IN RAM for more information.

Binary data is saved and read from the EPROM using
BSAVE and BLOAD commands. The EP ROM has a
limited number of write cycles (about 1000), so writing
information should be kept to a minimum.

This chapter discusses saving programs to EPROM (U6)
and program autoexecution.

SAVING A PROGRAM

For this example, assume you wanted to save the
following program:

20 FOR N= 0 TO 2
30 PRINT "Hello ",
40 NEXT
50 PRINT

If this progr am is not alr eady in, type it in now (or , if
you prefer, use your own program).

Type in the following command:

SAVE

RPBASIC-52 responds with:

Saving 35 bytes

Verifying --- OK

Page 3-1 RPC-320

SAVING PROGRAMS SECTION 3

The time it takes save a program depends upon the
length and complexity of the program and flash EPROM
type. Programming rate is roughly 600 bytes/second. If
the program is not successfully saved to EPROM, an
error message will appear.

Saving a program overw rites the pr evious one. Ther e is
no way to recover the old one since both occupy the
same space.

Using SAVE without any parameters is the same as
typing SAVE 0.

When a 128K (29C 010) or 5 12K (29C 040) EP ROM is
installed in U6, the SAVE segment parameter is 0 or 1
(128K) or 0 - 7 (512K). EXECU TE loads and runs the
program in the segment specified by SAVE. A 32K
(29C256) EPROM can run just one program.

Make the following modifications to the above program
as instructed to see how one program can call another.
There must be a 128K or 512K EPROM installed to run
this code.

Add the following lines:

10 PRINT "Program segment 0"
60 EXECUTE 1

AUTORUNNING

To autorun a program:

1. Make sure there is a program in EP ROM (from
above). When using a 128K or 512K size EPROM,
make sure the start up progr am w as saved to
segment 0.

2. Remove jumper W9.

Push the reset button. The program will run. If there
are any error s, the program will stop (assuming you
have not trapped them with ON ERROR) and display the
error m essage. EX ECU TE n is used within any
program to load and run another program. The EPROM
size must be a 128K or 512K.

PREVENTING AUTORUN

When troubleshooting a program, it' s not always
convenient for an autoexecute file to r un. This is
especially true if the program has been configured to
ignore the < ESC> or < Ctl-C> keys.

To prevent autorun, install jumper W9 before power up
or reset.

Now type:

SAVE 0

Now m odify lines 10 and 60 as follows:

10 PRINT "Program segment 1"
60 EXECUTE 0

Now type:

SAVE 1

To see the programs operate, type RUN. To stop program
execution, press < Ctrl-C> .

You may notice there is a slight pause between the
printed hello' s and pro gram segmen t number . This is
the time it takes to clear memory and load the program.
Loading and clearing take appr oximately 0.2 5 seconds in
a very small program up to 1 second in a very large
program.

LOADING A PROGRAM

There are tim es when y ou may w ish to tempor arily
modify or otherwise test out a change to a program.
Since the program is loaded into RAM in autorun,
modifications are m ade withou t affecting the pr ogram in
EPROM. Use the LOAD or LOAD n comm and to
transfer the EPROM program to RAM.

If you find out that modifications are not desirable or did
not work, you can restore the original program to RAM
using the LOAD command.

CHANGING EPROM SIZE

The RPC-320 can com e with a 32K or 512 K flash
EPROM . The size may be changed at any time. Set
W3 according to the type/size.

Type Size W3

Bytes Configuration

29C256 32K [3-5], [4-6]
29C010 128K [3-5], [2-4]

Page 3-2 RPC-320

SAVING PROGRAMS SECTION 3

29C040 512K [1-3], [2-4]

To change the EPRO M in U6, remove the IC and
replace it with the new one. When installing a 29C256,
pin 1 on the IC goes into socket pin 3. The top two
rows of pins are empty.

ALTERNATE EPROMS

Flash EPROMs are more expensive than UV er asable or
OTPs as of this writing. Large volume OEM' s may
wish to use lower cost EPRO Ms.

Program development must use flash EPROM s. When a
program is finished, the flash EP ROM is used as a
master. Use an exter nal progra m to duplicate progr ams.

Jumper W2 is normally configured for flash EPROM
(W2[3-5] and W2[4-6]). For non-flash E PRO Ms, W2 is
configured for [1-3] and [2-4]. Large volume OEM's
should contact Remote Processing regarding pre­configuring W2 and W3 for your application.

COMMANDS

The following is a list of RPBASIC-52 commands used
for saving, loading, and executing programs and data.
These commands and functions are explained in the
Software Supplement in this manual.

Command Function

BLOAD Transfers binary data from

EPROM to RAM

BSAVE Transfers binary data from RAM

to flash EPROM

EXECUTE Loads, clears memory, then runs

a program from within a program
LOAD n Loads a program from EPROM
SAVE n Saves a program to flash EPROM

Page 3-3 RPC-320

SERIAL PORTS SECTION 4

DESCRIPTION

The RPC -320 has two serial ports that interface to a
printer, terminal, RS-485 network, or other serial
devices. This chapter describes their characteristics and
how to use them. Fre quent ref erence s are m ade to
commands listed in the BASIC-52 Programming Manual
or RPBASIC-52 Software Supplement in this manua l.
Please refer to these manuals for more information about
these commands.

Serial por ts are num bered C OM0 and CO M1. COM 0 is
RS232 only and is used for progr am deve lopment.
During r un time, it can be used for other functions.
COM 1 is a general purpose port and is jumperable for
RS-232 or RS-422/485.

Each port has a 256 character interrupt driven input and
output buffer. This allows sending characters without
slowing down program execution. However, if the
PRIN T buffer fills, pr ogram execution is suspended until
all PRINT characters are in the buffer. Both ports have
a 256 character input buffer. When more than 256
characters are received, excess ones are ignored.

COM0 SERIAL PORT

This port uses a VTC-9F serial cable to connect external
serial devices to the port. The cable con sists of a 10 pin
IDC connector wired one-to-one to a DB-9 connector.
Line 10 is sim ply cut off. The pin ou t is designed so it
plugs directly into the 9 pin serial port connector on a
PC.

CTS is a output and is set to high on power up.
Normally, this tells the other device to send data. The
CTS line is set high or low to hold off communication.
The sending device must have a RTS input. Line 400
sets CTS high and 500 sets it low, or to hold off.

400 LINEB 5,0,(LINEB(5,0) .AND. 247)
500 LINEB 5,0,(LINEB(5,0) .OR. 8)

COM 0 is normally used for program ming. D uring run
time it may be used as a general purpose serial port.
When used for programming or with the INPUT
statement, it will accept ASCII character values from 0
to 127. When used with the GET function, it will return
ASCII values from 0 to 255.

CONFIG BAUD controls baud rate and RS-232/485
mode (COM1 only).

Figure 4-1 Serial port and jumper locations

ON C OM $ is useful whe n data is sent in pac kets. This
multitasking command branches to a BASIC subroutine
when a specific character or number of characters is
received.

Another useful function is STR. Strings can be
formatted, analyzed for length and content. When used
in conjunction with ON COM$, networ king over RS-485
is much easier than with the original BASIC-52.

COM1 SERIAL PORT

COM 1 is either an RS-232 or RS-422/485 port. A
VTC-9F serial cable, described above, is used for RS­232 level communications. RS-485 is from screw
terminals. COM 1 has 2 hardware handshaking lines,
CTS and RTS.

RTS is an input to the card. W hen RT S to the car d is
low, it usually indicates the sender does not want any
data sent to it. The status of this port is read by the
LINEB statement. The example below retur ns a status
of the RTS line:

100 B = LINEB(5,1) .AND. 32

If B = 32, the sender is not requesting information and
nothing further should be printed.

The CTS line may be set high or low to hold off
communication from a sending device. The sender must
recognize the CTS line. Line 400 sets CTS high and 500
sets it low, or to hold off.

Page 4-1 RPC-320

SERIAL PORTS SECTION 4

Figure 4-2 Network diagram

400 LINEB 5,0,(LINEB(5,0) .AND. 251)
500 LINEB 5,0,(LINEB(5,0) .OR. 4)

Jumper W4 determines if COM 1 receive is RS-232 or
RS-422/485.

W4[1-2] RS-485
W4[2-3] RS-232 (default)

COM1 default is RS-232. Use the CONFIG BAUD
statement to set the software to RS-422 or RS-485.
When set to RS-422, the transmitter is always on. RS­485 mode turns on the transmitter only when sending.

Page 4-2 RPC-320

RS-422/485 OPERATING INFORMATION

RS-422/485 Termination network

When the RPC-320 is the last physical unit on a network
(RS-485), or it is the only unit (RS-422), the receiver
must be terminated to prevent ringing. Jumper block
W5, 6 installs or removes this network. Insert a jumper
in W5 and W6 to install the network terminator.

Only one slave device on a RS-485 network should have
a terminator installed. The host transmitter should also
have a 100 ohm resistor in series with a 0.1 mfd
capacitor. T he term inator on the RPC -320 includes pull
up and pull down resistors to prevent lines from floating
and generating er roneous char acters.

SERIAL PORTS SECTION 4

Two wire RS-485

The RS-485 port on the RPC-320 is set up for 4 wire
mode. 2- wire mode causes transmitted data to be
received. To use the RPC-320 is this mode, your code
should "flush" the received data or otherwise remove
transmitted information.

Mechanically, to make a 2- wire system, simply connect
T+ to R+ and T- to R -. M ake sure CON FIG BAUD is
set up for RS-485 mode.

Multidrop Network

Figure 4-3 Data packet

You can use the RPC-320 in a multidrop network by
using CO M1' s RS-422/485 port. You can c onnect up to
32 units (including other RPC-320' s) over a 4,000 foot
range.

Figure 4-2 shows an example of a multidrop network.
This network includes a host and one or m ore devices.
The host transmits data packets to all of the devices, or
nodes, in the network. A data packet includes an
address, com mand, data, and a checksum. See figure 4-

3. The packet is received by all devices, and ignored by
all except the one addressed.

The response depends upon the nature of the command.
Suppose the command M means "return a digital I/O
port status". The RPC-320 could read the port and
respond with AA2< cr> . The first A is an
acknowledge, that is no errors were detected in the
message. The data, A2, is a hex number and is broken
down as follows:

Bit/line 7 6 5 4 3 2 1 0
Status 1 0 1 0 0 0 1 0 = A2

The relationship described below between nodes and the
host is a master-slave. The host dir ects all
communication. Nodes "do not speak unless spoken to".
Peer to peer communication, while possible with the
RPC-320, is not discussed here.

There are m any com municatio n protoco ls. F or this
example, a protocol might look som ething like this:

> 22MB1

The protocol starts w ith the < cr> charac ter. This
character synchronizes all units and alerts them that the
next few characters coming down are address and data.
In this case, "> 22" is the units address. "M " is the
comm and and " B1" is the ch ecksum . T he comm and is
terminated with a < cr> character.

Lines 1, 5 and 7 are high while the others are low.

The following program fragment uses ON C OM$ and
STR in a network environment. ON COM$ generates an
interrupt when a < CR> is received. The interr upt
program uses a STR function to deter mine if the da ta
packet was addressed to this card.

10 STRING 200,20
20 ON COM$ 1,0,13,1000
30 $(1) = ">05"

.
.
.

1000 $(0) = COM$(1)
1010 A = STR(8,$(0),$(1))
1020 IF A = 0 THEN RETURN

.
.

Line 20 sets up ON COM$ to interrupt on a < CR> and
branch to line 1000. Line 30 sets up this card' s address.

Line 1010 checks to see if the received message = this
card's address. If not, the subroutine ends. When there
is a match, further processing is performed.

ACCESSING SERIAL BUFFERS

Page 4-3 RPC-320

SERIAL PORTS SECTION 4

You can access C OM0 and COM 1 buffers in three ways:

1. INPUT statement. This re moves a ll charac ters in
the buffer up to the term inator cha racter and puts
them into a variable.

When using the INPUT statement, program
execution is suspended until a < cr> (Enter key) is
received. W hether this is a problem depends on
your particular application.

INPUT strips bit 7. This means ASCII characters
from 0 to 127 are received.

2. GET function. Char acters ar e removed one at a
time as an ASCII value. A 0 is returned when the
buffer is empty. Use the C OM function to
determine if the buffer is empty or if a 0 is an
ASCII value. Use UIn to select the serial port for
GET.

If you don' t read the b uffer an d the buffer fills, all
subsequent characters are discarded.

3. COM$(n) retrieves all characters in the buffer,
including other control codes (except CR).

ACCESSING COM0 AND COM1

INPUT and GET functions retrieve data using the UIn
comm and. UI0 r outes inputs to C OM 0 while U I1 inputs
from the COM1 port. PRINT outputs are set by the
UOn command. UO0 prints out COM0 while UO1
outputs COM1 using the PRIN T comm and. PR INT #1,
is an alternative way to print to COM 1.

The following show how UIn and UOn work.

100 UI0 Set to COM0
110 INPUT A Get data from COM0 port

DISABLING CONTROL-C

Program execution is terminated by entering a
< Cntl> < C> . To disable < Cntl> < C> so program
execution is not terminated, execute the following
statement:

DBY(38) = DBY(38) .OR. 1

COMMANDS

The following is a list of RPBASIC-52 commands used
for serial I/O. These commands and functions are
explained in the BASIC-52 Programming Manual and
RPBASIC-52 Software Supplement in this manua l.

Command Function

CLEAR COM$ Clears serial input buffer
COM$ Returns string from buffer
COM Returns number of characters

in buffer
CONFIG BAUD Sets serial port parameters
GET Returns a character from the

serial buffer
INPUT Receives string from port
LIST Outputs program listing
PRINT Outputs data in various

formats
PRINT #, Prints to a specified port
SPC Print out n number of spaces
STR String handling commands
TAB Tabs to predetermined

positions
UI0 Reroute inputs to COM0
UI1 Route inputs to COM1
UO0 Rerou te PRIN T statem ent to

COM0
UO1 Route P RINT statement to

COM1
USING PRINT formatting statement

520 UI1 Switch to COM1 port
530 INPUT B Get data from COM1 port

800 REM Print to COM0
810 PRINT "Temperature:",T

900 REM Print to COM 1
910 PRINT#1, "Set pressure at:",CA

Power up default is set to COM0.

SERIAL PORT PIN OUT

Pin outs for J1 and J2 are shown below. Unused pins
are open.

J1 & Name Direction
J2 from card

3 Tx Out

4 RTS* In

Page 4-4 RPC-320

SERIAL PORTS SECTION 4

5 RXD In
6 CTS Out

9 Ground
10 +5

*RTS input not in COM0.

A serial cable is made by simply taking a 10 pin female
IDC connector and crim ping a 9 wir e ribbon cable to it.

Page 4-5 RPC-320

RAM MEMORY SECTION 5

INTRODUCTION

32K, 128K, or 512K of RAM may be battery backed on
the RPC-320. RAM size can be changed at any time.
RAM is in socket U5.

RAM is backed up when a DS1216DM is installed.
Battery life depends upon RAM size, its power
consumption, ambient temperature, and amount of time
the board is operating. Generally, a battery life of about
3 to 5 y ea rs is e xpected . Op er ati ng the boar d a t 50 °C
reduces battery life by 1/2.

The DS1216DM is also a real time clock. Thus, DATE
and TIM E function s and com mands a re availa ble when it
is installed. See Chapter 7 for more inform ation.

This chapter discusses changing RAM, saving and
retrieving variables, running assembly language
programs, and battery condition. Figure 5-1 shows the
location of U3 and jumper W1.

Increasing RAM size does not necessarily increase the
program size RPBASIC-52 can handle. Maximum
program and variable size is 60K. Additional RAM does
increase the amount of space available for PEEK and
POKE storage.

To install a new memory chip:

1. Turn off power to the RPC-320.

2. Remove the mem ory chip from U 5.

3. Orient the chip so pin 1 is towards the inside.

If installing a 32K RAM, place the chip at the
bottom

of the socket (m emor y chip pin 1 goe s into
socket pin 3). The top two socket pins in each row
are empty.

If installing a 128K or 512K, install the chip into the
socket.

4. Check and change , as n ecessar y, jum per W1 to
conform to the new mem ory.

RAM size Jumper W1

32K [1-2]
128K [1-2]
512K [2-3]

BATTERY BACKUP

An optional battery backup module may be installed.
Principal is the same as installing a RAM chip.

Figure 5-1 RAM and W1 jumper location

CHANGING MEMORY

Different types of memory can be installed at any time.
RPC-320 models come with either 32K or 128K of RAM
installed. Maximum is 512K.

To change a memory chip, you need to rem ove the
original chip, install the new one, and set jumper W1.

WARNING:

An additional modification must be performed to the
DS1216DM module when a 512K RAM is installed.
Contact Rem ote Processing for details.

To install a module:

1. Remove the RAM IC in U5.

2. Install the DS1216DM in U5.

3. Re-install the RAM chip into the top of the module.

Checking the battery

Battery voltage is approximately 3.0 volts, measured
between pin 16 (ground) and 30 (128K RAM), 14 and 28
(32K RAM), or 16 and 32 (512K R AM ) on the IC itself
(not the circuit side of the board). Be sure to power up
the RPC -320 once to a ctivate the batter y backup circuit
in the module.

Page 5-1 RPC-320

RAM MEMORY SECTION 5

RESERVED MEMORY

Many control systems use process variables that are
operator entered. "variables" in this context include
numbers, strings, arrays, recipes, or formulas as applied
to your application. They are not a part of the variables
used by Basic. Process variables are accessed by PEEK
and POKE type statements.

The upper 512 bytes of mem ory ar e set aside for this
purpose in a 32K RAM system. In 128K and 512K
RAM systems, all of the first 64K of RAM is used for
program and variable stora ge. P rocess var iables in these
larger versions are stored starting at segment 1 and
higher.

Figure 5-2 RPBASIC-52 memory map

When the combined program and data size exceed 30K,
a 128K or 512K RA M is nec essary. Additional RAM is
necessary when your program has large arrays and / or
string storage requirements.

MTOP should not be used when variables are battery
backed for power off conditions. Basic clears all of
RAM in segment 0 (except for the last 512 bytes in a
32K system) at power up. Store process variables
starting at segment 1 or higher in a 128K or 512K RAM
system or start at address 7E00H, segment 0 in a 32K
RAM system.

STORING VARIABLES IN RAM

Program s and RPBASIC-52 var iables reside in segment

0. Data is generally stored in segment 1 and higher (a
segment is 64K of memory). See memor y map figure 5-

2. "Data Area" is segment 1 or higher.

PEEK and POKE commands store and retrieve values
from memory. For example:

20 POKEB1,12,A

puts the 8 bit value of A into segment 1, address 12.

100 POKEB0,7E00H,C
120 B = PEEKB(0,7E05H)

The highest address in a 32K RAM system is 7FFFH.

Many times it is desirable to store an array containing a
"mixed" set of variables. Suppose you needed to save an
array m ade up of the following elem ents:

Bytes Type Description
1 Byte Job counter
2 Word Analog output offset
6 Floating Correction factor
20 String Job name

Total number of byes required for each array is 30 (add
1 for a < CR> at the end of the string).

The Job counter is incremented ever y time it is
completed. Analog output offset is an output constant or
other var iable used to initialize the outputs. Job name is
used with the display to identify a job.

For this example, suppose there are 20 of these arrays
that need to be set up. A program fragment is as
follows:

Use the PEEK statement to retrieve the variable:

50 B = PEEKB(1,12)

Accessing reserved mem ory in a 32 K RAM system is
accomplished as follows:

100 STRING 400,20 Initialize 20 string arrays

300 NO = 12 Element to fill
310 CF = 23.432 Correction factor
320 JC = JC + 1 Job counter
330 AC = 25 Analog offset
350 GOSUB 1000

500 NO = 5 Element to retrieve

Page 5-2 RPC-320

RAM MEMORY SECTION 5

510 GOSUB 2000 Retrieve variables

This subroutine stores variables CF, JC, and AC into an
array starting in segment 1, address 0.

ASSEMBLY LANGUAGE INTERFACE

1000 POKEB1,30*NO, JC
1010 POKEW1,30*NO+ 1,AC
1020 POKEF1,30*NO+ 3,CF
1030 POKE$1, 30*NO+ 9,$(0)
1040 RETURN

Subroutine 2000 - 2040 retrieves data into variables CF,
JC and AC.

2000 JC = PEEKB(1,30*NO)
2010 AC = PEEKW (1,30*N O+ 1)
2020 $(1) = PEEK$(1, 30*NO+ 9)
2030 CF = PEEKF (1,30*NO+ 3)
2040 RETURN

You can store and retrieve strings and variables in this
way. There are many variations of PEEK and POKE
statements. Refer to the RPBASIC-52 Software
Supplement in this manual for additional information and
examples. A list of comm ands appea rs at the end of this
chapter.

BLOCK DATA TRANSFER

Blocks of data are transferred to and from RAM and
flash EPROM using BLOAD and BSAVE comma nds.
Block transfers are useful for loading and storing data,
look-up tables, text, etc. U p to 65,535 bytes can be
moved from RAM to EPROM or EPROM to RAM at
one time. The absolute number of bytes that are moved
is limited by the RAM and EPR OM sizes.

Transfers from EPRO M to RAM , using BLOA D, take
approximately 23.5 m s/1000 bytes. T ransfers from
RAM to EPROM , using BSAVE , are even longer at 100
ms/1000 bytes using a 512K byte EPROM. T his time is
even longer when smaller EPROM s are used (due to the
programming algorithm).

Serial port, tick timer, and external interrupts are
enabled dur ing these tra nsfers. However, response s to
ONT ICK or ONIT R are delayed by the time it takes to
transfer data. W hen ONTIC K or ONIT R must be
serviced faster, transfer data in smaller blocks.

Refer to BLOAD and BSAVE in Appendix A for more

information.

Assembly language programs must be placed in the
RPBASIC-52 EPROM . W hen using RPBASIC-52,
programs should start at addr ess 6000H or higher up to
7FFFH.

RPBASIC is norm ally in a 32K byte EPROM (27C256).
A 64K byte EPROM (27C512) may be used in socket U4
provided the following modification is made: Cut the
trace between W11 pins 1 and 2 on the circuit side.
(Jumper W11 is under socket U4. Pin 1 is designated by
the square pad.) Solder a jumper between W11 pin 2

and 3.

Docum ented assem bly language interface calls listed in
the Intel MCS BASIC -52 Users Manual will not work
with RPBASIC-52. This is because RPBASIC-52 has
been reassembled and code shifted around.

The RP-10 adapter boar d is used to run and debug
assembly and C code. This board plugs into RAM
socket U5 and RPBASIC socket U4. It does not use the
Basic at all.

COMMANDS

The following is a list of RPBASIC-52 commands used
with RAM.

Command Function

BLOAD Transfers data from EPROM to RAM
BSAVE Transfers data from RAM to EPROM
CALL Calls an assembly language routine

CBY Returns code memory data
DBY Returns or assigns internal memory
MTOP Sets top of RAM memory
PEEK B Returns a byte
PEEK F Returns a floating point number
PEEK W Returns a 16 bit value
PEEK $ Returns a string
POKE B Stores a byte
POKE F Stores a floating point number
POKE W Stores a 16 bit value
POKE $ Stores a string
XBY Returns or assigns external memory

Page 5-3 RPC-320

DIGITAL AND OPTO PORTS SECTION 6

INTRODUCTION

Digital I/O lines ar e used to inter face with op to-module
racks, switches, low current LED's, and other TTL
devices. The RPC-320 has 34 of these lines. 8 TTL I/O
lines go to a terminal strip. Additionally, there is one
high curr ent output and a n opto-isolated inp ut. R efer to
the figure below for the location of these lines.

Eight lines at P6 are intended for general purpose TTL
I/O such as switches, level sensors or to drive other
devices.

A 24 line connector, J3, is intended to interface to opto
racks or other TT L devices. 8 of these lines are high
current outputs, capable of sink ing 75 to 200 m a. O pto
modules on an opto rack sense presence of AC or DC
voltages or switch them.

L8 at P2 is a "zero" ohm FE T switch. It is intended for
switching L ED back lighting on an LCD display. This
line may also be used to switch high current, high
voltage power. It can switch up to 2 amps.

ISOA/B is used as an isolated input as well as an
interrupt.

technical support for suggestions appropriate to your

application. Power may be applied to ISOA/B at
any time.

Several softwar e comm ands support the digital I/O ports.
ON LINE br anches to a subroutine w hen a line changes.
ON COUNT counts the number of high to low
transitions at a digital line. Maxim um coun ting rate is
about 95 Hz. These commands simplify design and
greatly speed up execution. See Appendix A for more
information.

DIGITAL I/O PORTS

All ports use an 82C55 for I/O. Lines are accessed
using LINE or LINEB commands. Lines at J3 and P6
are configured for inputs or outputs using the CONFIG
LINE comm and. See Appendix A for information.

WARNING:

When using CONFIG LIN E, output lines go low
momentarily (less than 10 micro-seconds) until they
are set high again as per the data in the command
line. Some other lines are affected when CONF IG
LINE 0 is executed. Refer to CONFIG LINE
command in Appendix A for more inform ation.

In addition to the 24 I/O lines from J3, the display port
can be used as digital I/O. Refer to Chapter 8 for more
information.

Figure 6-1 Digital I/O

WARNING:

Apply power to the RPC -320 before applying a
voltage to the digital I/O lines to prevent current
from flowing in and damaging devices. If you

cannot apply power to the RPC-320 first, contact

Digital Por t J3

This port is used to interface opto modules (using the
MPS series racks), drive small r elays, solenoids,
motors, or lamps, and provide general purpose TTL I/O
to other logic devices or mechanical switches. The
LINE command is used to access and control this port.

The lines on J3 are divided into 3 eight bit groups from
an 82C55. Ports A and B are configured as all inputs or
outputs. Port C is progr amm ed as one group of 8 inputs
or outputs or as two groups of four lines (upper and
lower C). The four lines in upper and lower C can each
be programmed as all inputs or outputs. Refer to Table
6-1 to determine the opto channel or J3 pin number for a
port. Use CONFIG LIN E 100 (Appendix A) to
configure ports A, B, and C for inputs or outputs.

When a line is configured as an output, it can sink a
maximum of 2. 5 ma at 0.4V and can source over 2. 5
ma. Outputs sink 15 ma at 1. 0V. This will dr ive opto
modules. Port B is connected to a high current sink
through U12. See "High current output" later.

Digital I/O lines at J3 m ay be pulled up to + 5 volts or to

Page 6-1 RPC-320

DIGITAL AND OPTO PORTS SECTION 6

ground through a 10K/100K resistor packs using jumper
W7. 10K is on digital port A only.

Jumper W7 for pull up or down configuration is as
follows:

W7[1-2] Pull up
W7[2-3] Pull down

Setting W7 for pull up makes interfacing to switches and
"open collector" TTL devices easy. See "Interfacing to
Switches and other devices" below.

Digital Port P6

Connector P6 has 8 digital I/O lines for general pur pose
use. Additionally, 3 ground and a + 5V positions are
provided. + 5V power and gr ound may be brought in or
taken from this connector. Lines are numbered L0-L7.

This port may be used to interface switches, dr ive small
LED' s, and provide general purpose TTL I/O to other
logic devices. Voltage and current param eters are the
same as J3 except there is no high current output. Port
C from an 82C55 is used for this I/O.

Upon power up or reset lines L0 to L3 are inputs while
L4 to L7 are outputs. Lines L4 and L5 are low while L6
and L7 are high at power up. All lines are connected to
a 10K pull up resistor (R21). Lines are reconfigured for
all inputs or outputs using the CONFIG LINE 0
command, found in Appendix A.

to the touch. Consider the maximum ambient

temper ature the b oard w ill operate a t. A t 70°C, warm to
the touch at room temperature m ay be too much.
Consider adding a heat sink.

The PW M com mand m ay be used with this port. Use
the circuit in Figure 6-2 when switching inductive loads.
Use the "GN D" ter minal next to L8 when switching
loads.

Optically Isolated Input

ISOA and ISOB ar e inputs to an optica l isolator. This
input is read as L8. It can also generate an interrupt
provided W8[1-2] is jumpered and ONITR is set. Refer

to Chapter 12 for input voltage and interrupt

requirements. This line can be used to "wake up" the

CPU from low power IDLE 2 mode.

The status is read using the LINE(8) function.

A = LINE(8)

A 1 is returned when there is no input and a 0 when

voltage is sufficiently high enough to turn on the isolator

(about 3.5 volts).

The opto isolator is not polarity sensitive. This input can

be used in conjunction with or independently of the

ONIT R statem ent.

High Current Port L8

L8 will switch 2 amperes to ground through a "zero
ohm" FET switch. Maxim um off vo ltage is + 50 volts
DC. "ON" resistance is about 0.5 ohm.

Use this port to switch LED back lighting for LCD

displays on or off under softwar e control.

This line is always an output. Use the LINE 8 com mand
to turn this line off or on.

LINE 8,ON
LINE 8,1 Both commands turn on L8.

The F ET sw itch is rated fo r mu ch higher curr ent.
However, continuous current is much less without a heat
sink attached. You may draw more than the rated 2
amps on an intermittent basis. How m uch and for how
long depends upon your application. A quick w ay to
check for excessive current is to touch (VERY
CAREFUL LY!) Q2 (next to P2). It can be warm to hot

Page 6-2 RPC-320

Digital I/O Commands

The CONFIG LINE statement is used to configure lines

at J3 and P6 for inputs and outputs. J3 power up default

is all inputs. P6 power up default is L0 to L 3 are inpu ts

and L4 to L7 are outputs. CONFIG LINE 0 refers to P6

while CONFIG LIN E 100 to J3.

The L INE comm and has 3 variations: LIN E, LIN E B,

and LINE #. Each is described below. See Appendix A

for more inform ation.

LINE function and statement is used with M PS-X X opto

rack at J3. It accesses a module according to the

position number printed on the MPS board. Lines are

numbered from 100 to 123. The opto module number

used in this command is computed by adding 100 to the

board position number. LINE also accesses L0-L8 on

P2 and P6.

The LIN E B function and statement is used to acc ess

DIGITAL AND OPTO PORTS SECTION 6

digital I/O lines 8 bits at a time. T he addr ess for po rt A
is 0, B is 1, and C is 2. J3 I/O bank number is 3.
Address for lines L0-L7 at P6 is 2 and I/O bank number
is 5.

LINE # function and statement accesses lines according
to the pin number at J3. J3 lines are numbered from 101
to 125. The line number used in this com mand is
computed by adding 100 to the connector pin number.
Line 102 is not allowed as it is the + 5V supply. See
table 6-1 to cor respond a pin numb er to a por t and opto
rack position.

P6 lines are numbered 0 to 7, and correspond to the
terminal number on the board. The LINE function and
command are used to access these lines. L8 at P2 is a
high current output and is accessed using LINE 8. The
status of ISOA/B is returned using LINE 8 function.

LINE, LINE B and LIN E # return a ' true' logic level.
A ' 1' indicates + 5 volts or high and a '0' is low or
ground. LINE B and LINE # output true logic levels.
LINE, however, outputs inverted logic. In order to turn
on an opto m odule, a line must go low. Howe ver, to
turn on a module using LINE, specify ' 1' or ON. High
current output chip U 12 inverts c ontrol signa ls sent to it,
regardless of command.

100 LINE 118,1 :REM Turn opto 118 ON
110 LINE 118,ON :REM Turns opto 118 ON
120 LINE#104,0 :REM also turns 118 ON

ON LIN E is a multitasking command. W hen active, the
RPBASIC oper ating system checks the specified line
every 5 ms. If the line changed state from the previous
scan, a software interr upt is set. Upon completion of the
current BASIC command (and assuming no other
interrupts are active), program execution branches to a
specified subroutine. This command is useful for
monitoring lines, such as limit or door switches, that
may not change often or when the program structure
make it unwieldy to check lines frequently.

Another multitasking command, ON C OUN T, causes the
operating system to check the specified line every 5 m s.
Up to 8 lines are monitored. If the line changed from a
high-to-low state, a counter is incremented. M aximum
counting rate is effectively 95 Hz. This command has
two variations. One causes a software interr upt when a

specified num ber of co unts is reac hed. Another simply
counts pulses at a line. The C OUN T function returns
the number of pulses since ON COUNT was initiated.
See Appendix A for command information.

ON C OUN T and ON LIN E do not ne cessarily h ave to
be input lines. They can be outputs controlled by
another part of the program.

High Current Output

Eight lines at J3 can be used as high current driver s.
These outputs will switch loads to ground. Outputs are
controlled by Port B on the 82C55.

Logic outputs are inverted. That is, when a 1 is written
to the high current port, the output is switched on and
goes low.

The output driver chip, U 12, can be replaced w ith a DIP

shunt jumper so it is like the other lines at J3. To do

this, r emove U12. Install a DIP shunt so pin 1 goes to

pin 18. Pins 9 & 10 are open.

NOTE: Outputs at the high current lines are not

compatible with TTL logic levels and should not
be used to drive other logic devices.

Each of the high current outputs can sink 500 ma at 50V.

However, package diss ipation will be ex ceeded if all

outputs are used at the maximum rating. The following

conservative guidelines assume the number of outputs

are on simultaneously:

# of outputs Maximum current

on per output

1 500 ma
2 400 ma
3 275 ma
4 200 ma
5 160 ma
6 135 ma
7 120 ma
8 100 ma

The ther mal time constant of the p ackage is ve ry shor t,

so the number of outputs that are on at any one time

should include those that overlap even for a few

milliseconds.

Incandescent lamps have a "cold" current of 11 times its

operating current. Lamps requiring more than 50 ma

should not be used unless a series resistor is installed.

Page 6-3 RPC-320

DIGITAL AND OPTO PORTS SECTION 6

Protection diodes m ust be used with inductive loads.
Refer to figure 6-2

Figure 6-2 Inductive load protection

Do not parallel outputs for higher drive. This could
result in damage since outputs will not share current
equally.

The outputs at U12 are open collector. An external
device must supply power.

Interfacing Digital I/O to an opto-module rack

I/O lines at J3 can interface to an MPS-8, 16, or 24
position opto module rac k. L ines not going to an opto
module connect to a screw terminal on the MPS-XX
series boards. This feature allows you to connect
switches or other TTL type devices to the digital I/O
lines. The MPS-XX series boards accept G4 series
modules.

A CM A-26-24 connects J3 on the RPC-320 to the MPS­XX board. Cable len gth should be less than 2 feet.
Excessive cable lengths cause a voltage drop and
consequently unreliable operation. Make sure + 5 V and
ground is connected to the M PS-XX racks.

Before a line is set, the 82C55 chip must be initialized.
This is done using the CONFIG LINE statement. Group
inputs and outputs together. Refer to Table 6-1 for opto
module position, port number, and connector pin out. If
opto channels 16-23 are used, U12 should be replaced by
a DIP shunt jumper.

130 A = LINE#(103) Function

Program line 100 turns external opto module rack
position 0 off. Program line 110 sets J3, pin 3, to a
logical 0 level. Program line 120 returns the status of
external opto module rack position 0. If the module is
"off", a 1 is returned (assuming it is an output module).
Program line 130 returns the status of J3, pin 3 as a 0 or

1.

Example: To turn on opto module in slot position 8, the
following command is executed:

LINE 108, 1

A ' 1' turns on a module while a 0 turns it off. (In actual
fact, a 0 is written at the port. )

See Digital I/ O program ming exam ple later in this
chapter.

Interfacing to switches and other devices

Switches and other digital I/O devices may be connected
directly to P6 or J3. The STB-26 terminal board
provides a convenient way of interfacing switches or
other digital I/ O device s. L ines at J3 are connected to
the STB-26 with a CMA-26 cable. Digital devices are
then connected to the screw terminals on the STB-26.
The M PS-X X serie s opto rac ks also provide a way to
access digital I/O lines.

Switches may be connected directly to a line. When
jumper W7 configures the resistors as pull ups, a switch
closure to ground at a line is read as a 0 using the LINE
# function at J1. 10K resistors are always pulled up at
lines L0 to L7.

When W7 configures the input resistors as pull downs,
one end of the switch must be tied to + 5 volts. If this is
not possible or convenient, a 1K resistor can be tied
between an input and + 5 volts to force it high when a
switch is open.

The LINE and LINE # com mands are used to control
and access opto modules and lines. These commands are
both functions and statements, depending upon how they
are used.

100 LINE 100, 0 Statement
110 LINE #103, 0 Statement
120 A = LINE(100) Function

Page 6-4 RPC-320

Digital I/ O prog ramm ing exam ple

The follow ing exam ple read s a switch at po rt A, bit 3
(J3-25) (program line 200), reads L1 at P6 (program line

210) and turns on opto module at channel 5 (program
line 220). A LED is controlled through the high current
port at J3-10 (port B, bit 0) (program lines 230 and 240).
For testing, a 100 ohm resistor from J3-10 to + 5 volts
can be substituted.

DIGITAL AND OPTO PORTS SECTION 6

100 CONFIG LIN E 100,13, 1,1, 1
200 D = LINE #(125)
210 F = LINE (1)
220 LINE 105, 1
230 LINE #110,1 :REM Turn on LED
240 LINE #110,0 :REM Turn off LED

Line 100 configured the 82C55 so ports A and C are
inputs while B is the output.

Note that the LINE statement is us ed to contr ol both opto
modules and individual lines.

Lines can also be read or controlled in the immediate
mode.

PRINT LINE#(125)

returns the status at J3-25. Notice that even when a line
is configured as an output, its status can be read back.

Execute the following to control L7.

LINE 7,OFF

sets L7 low. Executing

LINE 7,ON

sets the line high.

LINEB is used to read and write a byte at a time.

LINEB 3,1,128

sets port B, bit 7 high and bits 0-6 are low.

Pulse Width Modulation (PWM)

Any line accessible by the LINE com mand m ay be pulse
width modulated. PW M comm and parameters determ ine
high and low time (to 5 ms resolution) and, optionally,
number of pulses.

Use PWM to control the brightness of a display (via line

8), control the speed of a motor, or output a number of
pulses to a stepper controller. Brightness control using
LED' s is best achieved when htime or ltime are less than
5 (25 ms). One of the parameters should be 1.
Noticeable flicker occurs when htime and ltime sum to
more than 6 (30 ms).

See the PWM command in the Software Supplement for
more information. Use Table 6-1 to use an output

directly from J3.

Page 6-5 RPC-320

DIGITAL AND OPTO PORTS SECTION 6

Table 6-1 Connector pin ou t - J3

Pin # 82C55 Description Opto

Channel

19 Port A, line 0 8
21 Port A, line 1 9
23 Port A, line 2 10
25 Port A, line 3 11
24 Port A, line 4 12
22 Port A, line 5 13
20 Port A, line 6 14
18 Port A, line 7 15

10 Port B, line 0 High current 16
8 Port B, line 1 High current 17
4 Port B, line 2 High current 18
6 Port B, line 3 High current 19
1 Port B, line 4 High current 20
3 Port B, line 5 High current 21
5 Port B, line 6 High current 22
7 Port B, line 7 High current 23

13 Port C, line 0 Lower C 0
16 Port C, line 1 Lower C 1
15 Port C, line 2 Lower C 2
17 Port C, line 3 Lower C 3
14 Port C, line 4 Upper C 4
11 Port C, line 5 Upper C 5
12 Port C, line 6 Upper C 6
9 Port C, line 7 Upper C 7

26 Ground
2 +5V

Figure 6-3 Digital I/O connector pin out (viewed from top)

Page 6-6 RPC-320

DIGITAL AND OPTO PORTS SECTION 6

COMMANDS

The following tables shows the RPBASIC-52 commands
used for digital I/O.

Command Function

CONFIG LINE Configu res I/ O por ts
COUNT Returns number of pulses at a line.
LINE Function returns status of an opto

module as a 0 or 1.

LINE Statement turns on or off an opto

module.

LINE B Function returns 8 data bits from any

I/O type device.

LINE B Statement writes 8 data bits to any I/O

type device.

LINE # Function returns status of line at J3

connector as a 0 or 1.

LINE # Statement writes data to a line at J3

connector as a 0 or 1.

ON COUNT Counts pulses and optional generates an

interrupt.

ON LINE Generates an interrupt when a line

changes.

PWM Sets PWM parameters for any line.

Page 6-7 RPC-320

CALENDAR/CLOCK SECTION 7

DESCRIPTION

An optional DS1216DM calendar/clock module may be
installed in U5. The DS1216DM also battery backs
RAM.

The DS1216DM from Remote Processing is a modified
version of the Dallas DS1216D. An internal reset line
has been cut. When a 512K RAM is installed, an
additional line is cut and another soldered. Contact
Remote Processing for details.

Battery life depends greatly upon the ambient
temperature. Battery life degrades up to 50% at 50°C,
using 25°C as a reference. RAM size and type also
affect battery life. Generally, you can expect a battery
life of 3 to 5 years.

Accuracy is about 1 minute/month and is not adjustable.

Hours are expressed in 24-hour fo rma t.

Refer to the RPBASIC-52 Software Supplement for
more command information.

NOTE: The clock module is turned off as shipped from

the factory. DATE and TIME functions return
a HARDW ARE erro r until DA TE is set first.

To retrieve date and time as part of a program:

100 PRINT "Time: ",
110 FOR N=0 TO 2
120 PRINT TIME(N),
130 NEXT
140 PRINT "Date: ",
150 FOR N=0 TO 2
160 PRINT DATE(N),
170 NEXT
180 PRINT CR,
190 GOTO 100

run

Time: 13 24 12 Date: 94 11 14

When the clock module is missing, defective, or the date
has not been set, a HARD WARE er ror (code 50 at
address 101H) is returned by RPBASIC when a DATE
or TIME function is performed. Use ONE RR to trap for
this error and report the problem.

The clock module is installed by first r emoving the IC in
U5. Then, install the DS1216DM into the socket. Install
the RAM chip into the socket. When installing a 32K
RAM chip, the top two pins in the DS1216DM are left
open.

Refer to CHAPTER 5 for information about using battery
backed RAM and jumper setting when installing a 512K
RAM.

WARNING: An additional modification to the

DS1216DM is necessary when
installing a 512K RAM. Contact
Remote Processing for details.

SETTING DATE AND TIME

Set the date to turn on the clock module. Date and time
are set while running a progr am or in the imm ediate
mode. Date and time are treated as number s and not
strings. To set the date and time:

DATE 95,11,28
TIME 13,23,43

COMMANDS

The following is a list of RPBASIC-52 commands for
the calendar/clock.

Command Function

DATE Sets date and tur ns on mod ule
DATE(n) Returns date
TIME Sets time
TIME(n) Returns time

The time is set to 1:23:43 PM.

Page 7-1 RPC-320

CALENDAR/CLOCK SECTION 7

Figure 7-1 Calendar/Clock

Page 7-2 RPC-320

DISPLAY PORT SECTION 8

INTRODUCTION

RPBASIC-52 and the RPC-320 interface to a variety of
displays:

VF (vacuum florescent) character
LCD (liquid crystal) character
LCD graphics

Character display sizes range from four lines by 20
characters to four lines by 40 characters. The graphics
display supports 160 x 128 pixels. Remote Processing
supplies these displays with appropr iate cables. A
contrast adjustment for LC D char acter disp lays is built
into the card.

If a display is not used, this port may be used for general
purpose digital I/O. Port A and part of port B from an
82C55 are available. See CONNECTOR DISPLAY PIN
OUT below for available lines.

The cable length to a display depends upon the amount
of current it requires. A significant amount of voltage
drop occurs with a long cable. Vacuum florescent and
LCD graphics cables should b e less than 2 fee t. A
character LC D display c able should be less than 5 feet.

Additional power wiring is usually required for LCD
graphic and VF charac ter displays. This information is
included with the display. Information content is display
dependent. Below is general information on both.

Graphic displays require additional voltages not
generated on the RPC-320. These must be supplied
externally. An external contrast adjustment may be
necessary. You may be able to connect these through
screw terminal block P5.

VF character displays r equire + 5 volts and ground to
connector P5. This may in the form of external wires
from the main power connector on the board or power
supply.

Additional information for commands mentioned in the
following text are found in the RPBASIC-52 Software
Supplement in this manual.

WRITING TO THE DISPLAY

The display type must first be set using the CONFIG
DISPLAY command. T he DISPLAY com mand is used
to print information.

Figure 8-1 Display interface

CONNECTING DISPLAYS

The display port is designed to supply all the lines
necessary for VF and L CD displays. A custom cable
connects the RPC-320 to the display.

Displays purchased from Remote Processing include a
cable. You simply connect the 20 pin connector to the
RPC-320 LCD display port and the other end into the
display.

PROGRAMMING EXAMPLE

The example below is for a four line by 20 character
LCD display. Even though DISPL AY statements do not
end with a comma (, ), a < cr> < lf> sequence is not
sent. Use CR to force a return to the beginning of the
line. A CR does not scroll characters on a display. You
must position the cursor to the next line.

10 CONFIG DISPLAY 1
20 STRING 200,30
30 $(0) = "Hello world"
40 DISPLAY (1,2),$(0)

Page 8-1 RPC-320

DISPLAY PORT SECTION 8

DISPLAY TYPES

RPBASIC-52' s software driver is based upon the
characteristics of the display family. Compatible VF and
LCD displays are shown below:

Manufact. Model Type

Optrex DMC 40457 LCD 4 x 40
Optrex DMC 40202 LCD 2 x 40
IEEE 3601-90-080 VF 4 x 20
Optrex DMF 682N LCD 160W x 128D

DISPLAY CONNECTOR PIN OUT

The display port uses an 82C55 for data and control.
The table below lists a pin number and its intended
function. A display may not use all lines even though
they are available.

J4 8255 Function
Pin Port/line

1 Logic + 5V
2 Digital ground
3 A/4 D4
4 Contrast voltage
5 A/6 D6
6 A/5 D5
7 B/4 Reset (from invertor)
8 B/3 Write
9 B/2 Read
10 A/7 D7
11 A/1 D1
12 A/0 D0
13 A/3 D3
14 A/2 D2
15 B/7 CS (from invertor)
16 B/6 Command/ data
17 B/5 Halt
18 Contrast adjust
19 Alternate power
20 Power ground

COMMANDS

The following RPBASIC-52 com mands are used for the
display.

Command Function

CLEAR DISPLAY Clears entire display
CLEAR DISPLAY LINE Clears current line
CONFIG DISPLAY Specifies display type to

use

DISPLAY Prints the string at the

row and collum specified

J4 is available for additional I/O if a display is not used.
Port A is configured as an input or output. Port B must
be configur ed as an outpu t if a 17 key or larger keypad is
used. Use the L INE B comm and to acces s this part.
I/O bank is 4.

Pins 18, 19, and 20 are for the LCD -5003 and other
graphic displays.

Page 8-2 RPC-320

KEYPAD PORT SECTION 9

INTRODUCTION

16, 20, or 24 position keypads are plugged into keypad
port J5. Keys are arra nged in a m atrix for mat. A key is
recognized when a row and a colum n connect.

10 STRING 200,20
20 $(0) = "123A456B789C*0#D"
30 P = 1
40 PF = 0
50 PRINT "Enter a number from the keypad",

RPBASIC-52 scans and debounces the keypad every 50
ms. Keypad pr esses are retur ned as a num ber from 1 to
24 using the KE YPA D function . Ke ypad scann ing is
always active and cannot be turned off. Up to 8 key
presses are buffered.

Keypad presses are multi-tasked using ON KEYPAD.
When a key is pressed, the program branches to the
subroutine.

Keypads from Remote Processing simply plug into J5.
The keypad cable length should be limited to less than 5
feet.

REM Rest of program continues
REM Scan keypad and update display

200 GOSUB 500
210 IF PF = 0 THEN 200
220 PRINT
230 PRINT "Entered string is: ",$(2)
240 PF = 0
250 GOTO 50

500 A = KEYPAD(0)
510 IF A = 0 THEN 500
520 IF A = 12 THEN 600 : REM Process clear
530 IF A = 16 then 700 : REM process enter
540 A=ASC($(0),A)
550 PRINT CHR(A),
560 ASC($(2),P) = A
570 P = P + 1
580 ASC($(2),P) = 13
590 RETURN
600 REM Clear input string
610 $(2) = ""
620 P = 1
630 RETURN
700 REM Enter processing
710 P = 1
720 PF = 1
730 RETURN

Program explanation

Figure 9-1 Keypad connector

PROGRAMMING EXAMPLE

The following example sets up RPBASIC to scan a 16
position keypad. T he results are echo ' ed when a key is
pressed. Press the 'D' key to enter.

Line 20 defines the keypad legend. Letters may be
redefined as necessary.

Line 30 sets the position counter used to insert characters
into the string.

Line 200 w aits for a ke y press. The enter ed string is
printed.

Line 500 checks the keypad. If a character is available,
it processes it.

Lines 540-590 update the input string and position. A
< CR> is inserted to mark the end of string.

Page 9-1 RPC-320

KEYPAD PORT SECTION 9

The second example uses ON KEYPAD to generate an
interrupt every time a key is pressed.

10 ON KEYPAD1000

.
.
.

500 GOTO 500

1000 PRINT KEYPAD(0)
1100 RETURN

Line 10 sets up the tasker for keypad interrupts to start at
line 1000. Line 500 loops on itself for demonstration
purposes.

Line 1000 prints out the key pad position pressed.

Elements of the previous program can be com bined with
this one to produce keypad strings.

KEYPAD PORT PIN OUT - J5

The keypad port uses ports B and C from an 82C55.
Lower port C is configured as an input. Upper port C
and port B bits 0 and 1 are outputs.

The table below lists J5' s pin out, 82C55 p ort and bit,
and its intended function.

Pin 82C55 Function

Port/ bit

1 C/0 Row 1
2 C/6 Column 3
3 C/5 Column 2
4 C/1 Row 2
5 C/2 Row 3
6 C/4 Column 1
7 C/7 Column 4
8 C/3 Row 4
9 B/0 Column 5
10 B/1 Column 6

Page 9-2 RPC-320

ANALOG INPUT SECTION 10

DESCRIPTION

The RPC-320 has 8 single ended analog input channels.
These channels are used to measure voltages from
transducers, 4-20ma current loops, thermistors, etc.
Input voltage r ange is 0 to 5 volts or ±2.5V with 12 bit
(4096 count) resolution. Signals are single ended or
differential. Input impedance is 100K ohms to ground.

Reference IC U 14 has a voltage output that corresponds
to the IC tem peratur e. T his output may be used to
measure ambient temperature.

Two am plifiers are available to signal condition inputs.
By installing appropriate r esistors and capacitor s, inp uts
are buffered, amplified, and filtered.

This chapter begins with basic information on connecting
and using analog inputs. Later , de scriptions of how to
measure voltages other than 2.5 or 5 volts, temperature
measurement, data logging, using the amplifiers, and
calibration are presented.

CONNECTING ANALOG INPUTS

usually affects readings on other channels.

Grounding

Analog ground is somewhat isolated from digital ground.
While the ground plane is connected between the two,
analog ground is a virtual "island" connected only in one
place to digital ground. To minimize noise pickup, the
sending device should be connected to analog ground
(located at the analog input terminal strip). W hen both
analog and digital grounds come from the same device,
you will have to play around with the grounds to
determine which scheme provides the best performance
for your system.

All analog inputs interface through connector P4.
Additional components, such as resistors and capacitors,
may be connected directly to the screw terminals.

For greatest accuracy, connect unused inputs to ground.

R17 is adjusted to trim accuracy to your system. See
Calibration later in this chapter for more information.

Temperatur e output or other signa l input may g o directly
to channel 0 via header H1. See Temperature
Measurement and Amplifiers below.

Overvoltage conditions

Inputs are protected over voltage protected. M aximum
voltage on 1 channel is 25 volts. Maximum voltage for
2 to 4 channels is 12 volts. Total input current may not
exceed 16 ma on all channels. Each channels input
current is computed by the following formula:

Iin = (Vin - 5)/4700

When V

NOTE: An over-voltage condition on one channel

< 5 volts, no current flows into the channel.

in

Figure 10-1 Analog I/O

INITIALIZATION

Each channel is initialized for 0-5V, single ended input
upon power up. Inputs can be reconfigured for eight
single-ended, four differential, or a mixture of single-

ended and differential inputs. Input voltage ranges are 0

to 5V or ±2.5V for any single-ended channel or

differential pair. Syntax is:

CONFIG AIN channel,mode, range

channel ranges from 0 to 7 for single-ended inputs.

Differential inputs use adjacent channels.

mode defines single-ended or differential. 0 =

differential, 1 = single-ended.

Differential inputs operate in a special way. The

polarity of the input signal must be connected as shown

for an even or odd channel. For example, when channel

is odd (1, 3, 5, or 7), channel 0 m ust be more negative

than channel 1 otherwise a 0 is returned. Should the

relative polarity change, configure the even channel for

differential input and perform an AIN on it. Use the

Page 10-1 RPC-320

ANALOG INPUT SECTION 10

following tables for differential inputs.

When channel = odd

Pol. - + - + - + - +
CH # 0 1 2 3 4 5 6 7

channel 1 3 5 7

When channel = even

Pol. + - + - + - + ­ CH # 0 1 2 3 4 5 6 7

channel 0 2 4 6

When range = 0, the input is ±2.5 volts and a 1 = 0 to
5 volts.

Differential Mode

When differential m ode is specified , inpu ts are actu ally
pseudo-differential. What this means is that a ground
reference is needed. For example, you cannot place a
battery between channel 0 and 1 and get an accurate
reading. The (-) input must be referenced to ground.
An example of where pseudo-differential works is an
output from a bridge network.

A pseudo-differential input subtracts the DC component
from an input. The IC maker recommends the (-) input
remain stable within 1 count with respect to ground for
best results. Connecting a 0.1 uF capacitor from the (-)
input to ground works well.

Perform a conversion as normal:

A = AIN(0)

The difference between channel 0 and 1 is returned.
When channel 1 is more positive than channel 0, the
result is zero. The difference is read on channel 1 by
performing:

A = AIN(1)

Single-ended, ±2.5V input

CONFIG AIN channel,1,0

The result is 0 for -2.500V input, 2048 for 0.000V, and
4095 for + 2.4988V.

Acquiring Analog Data

Analog data is accessed with the AIN function. The
syntax is:

A = AIN(channel)

This function assigns the analog value of a channel to the
variable; A in this case. The value returned is always in
the 0 to 4095 range because the converter is 12 bits.
Power up or reset default configures inputs to the 0-5V
range, single ended.

To view the result of a conversion in the command
mode, type:

When operating in differential mode, relative + and ­voltages must be connected to specific inputs. When
inputs are reversed, a conversion returns a 0. When the
relative voltage changes, perform a conversion on the
alternate channel. CON FIG AIN is performed on both
channels.

Pairs of channels can be differential while others single
ended. Thus, if channel 0 and 1 are differ ential inputs,
channels 2-7 may be single ended.

Examples u sing CON FIG AIN

Below are sample syntaxes for CONFIG AIN

Differential, 0 to + 5V input

CONFIG AIN 0,0, 1
CONFIG AIN 1,0, 1

Page 10-2 RPC-320

print ain(0)

The result at channel 0 is returned. The returned value
will always be in the 0 to 4095 range. When using a
channel in the ±2. 5V ra nge, the value r eturned is
interpreted differently. Zero count is now -2.500V,
4095 is + 4.9988, and 2048 is 0.000V.

Use the following formulas to convert a returned number
to a voltage:

0 - 5V A = .001221 * AIN(channel)

±2.5V A = .001221 * ain(channel) - 2.5

The AIN function requires about 1.5 ms to convert the
data. Additional time is needed to store the data. The
example below takes 255 data samples and stores them

ANALOG INPUT SECTION 10

into an array which requires 6 bytes per entry. The
second example takes only two byes per entry, can save
to extended m emor y, b ut requir es a longer time to get a
data point.

The program below take s about 1. 5 ms per data point.

10 DIM A(254)
20 FOR X=0 TO 254
30 A(X) = AIN(0)
40 NEXT

This next program saves data above MTOP . M TOP was
previously set. However, if you have 128K or more
RAM, you can POKE into segment 1 or higher. It takes
approximately 2 mS per data point and is not affected by
the memory location saved to.

10 A = 30000
20 FOR X=0 TO 999
30 POKE W0,A,AIN(0)
40 A=A+2
50 NEXT

Data is retrieved using the PEEK W command.

Noise Notes

An input channel can appear noisy (change readings at
random) if unused inputs are allowed to float. To
minimize noise (and increase accuracy), connect all
unused inputs to ground.

A high impedance input is, by definition, sensitive to
voltage pickup. Noise is minimized by running wires
away from AC power lines. A low impedance voltage
source helps to reduce noise pick up. Shielded cable can
help reduce noise from high impedance sources. Make
sure the shield is not used for power ground. Using the
shield for power ground defeats its purpose.

Wire pairs can also be twisted. 5-6 twists/foot provides
a reasonable amount of noise cancellation.

Noise is defined in this section as any random change
from a known input. The amount of noise you can
exp ect und er nor ma l op er atin g ci rcumstance s is ±3
counts for any input range.

period of time (several seconds if possible).

Another way is place a capacitor (0.1 to 1 mfd) between
the input terminal and ground. This is useful when the
source resistance is high.

Noise is, by definition, random. If you were to plot out
the deviations from a norm, it would roughly resemble a
bell shaped curve. Exper iments on the RPC-320 have
shown that 99% of the readings are within the ±3 count
reading and 60% are ±1 count. Noise readings were
made with all inputs shorted to ground.

Temperature Measurement

Reference IC U14 outputs a voltage pr oportiona l to its
temperature. This information is used to determine
approximate ambient temperature in order to turn on
fans or heaters.

Vo = 2.1(T + 273)

or

T = Vo/2. 1 - 273

or

T = Vc * .581428 - 273

Where T = Te mp eratu re in °C

Vo = Output voltage in mV
Vc = Count returned using AIN , 0 -

5V range

At 25°C the output voltage is approximately 625 mV, or
506 counts. Vo is expressed as a milli-volt number
(625) not .625.

The output from U14 must be buffered. To measure
temperature, jumper H1[1-3]. Remove resistor R13.
Jumper H1[2-4]. Temperature is read at analog channel

0. T he sensitivity is incr eased by jum pering H 1[5-7] to
ground. T his will double the output voltage and any
voltage changes due to temperature.

100 T = AIN(0) * .581428 - 273

T returns the temperature in celsius.

One way to compensate for noise is to take a number of
samples and average the results. Taking 6 or more
samples would, in theory, cancel out any effects of
noise. A problem with this is noise tends to group
together. Taking 6 readings at one time might show no
change fr om the norm. Another 6 readings might be all
high. If possible, try to spread out readings over a

Page 10-3 RPC-320

Sensitivity is increased by jumpering H1[5-7] to ground.

This doubles the output voltage and any voltage changes

due to temperature.

NOTE: Temperatur e measu rem ents are a pproxim ate

and are meant as a guide to indicate ambient
temperature.

ANALOG INPUT SECTION 10

The output from the temperature sensor varies from unit
to unit. Self heating effects as well as supply voltage
will change the output.

Page 10-4 RPC-320

ANALOG INPUT SECTION 10

The output voltage from the tem peratur e sensor is
doubled by jumpering H1[5-7]. While this does not
change the range the unit operates at, it does change
increase temperature m easurement sensitivity.

Data logging on a timer tick

Some applications require that data is read at fixed
intervals. The O NTI CK con struct is used to take data in
intervals from 0.01 to 327 seconds. The example below
takes 1 sample per second until 100 samples have been
obtained.

10 DIM A(100)
20 ONTICK 1,500
30 REM THE REST OF YOUR PROGRAM
40 REM CONTINUES
80 GOTO 30
500 A(N) = AIN(3)
510 N=N+1
520 IF N = 100 THEN ONTICK 0,500
530 RETI

MEASURING HIGHER VOLTAGES

Voltages higher than + 5V are measur ed by inserting a
series resistor to the input.

The table below shows resistor values for some input
voltages using the 0-5V range.

Maximum
Input Voltage Resistor

6 20K

12.5 150K
24 380K

Use the following formula to determine the series
resistance necessary for a m aximum voltage input:

Rs = Vi * 20000 - 100000 0 - 5V range
Rs = Vi * 40000 - 100000 0 - 2.5V r ange

Rs is the resistor value in ohms in ser ies with the inpu t.
Vi is the maximum input voltage. When Rs is negative
or zero, a series resistor is not necessary.

A high Rs value can cause noisy readings. This is

because the resistor acts as an antenna. To reduce noise,
place a 0.1 mfd to 1 mfd capacitor between the input
terminal and ground.

NOTE: When an input voltage exceeds the input range,
other channel values are affected.

Page 10-5 RPC-320

ANALOG INPUT SECTION 10

CONVERTING ANALOG
MEASUREMENTS

Inputs are converted to "real numbers" by performing
scaling calculations in the program. The AIN function
returns values from 0 to 4095. To change these numbers
into something more meaningful, use the following
formula:

var = K * AIN(n)

n is the analog channel to read. K is the scaling

constant. K is obtained by dividing the highest number
in the range of units by the maximum AIN count (4095).

Example 1: To measure the results of an A/D
conversion in volts and the voltage range is 0 to 5V,
divided 5 by 4095 to obtain K.

K = 5/4095
K = .001221

Your program could look something like:

1000 C = .001221 * AIN(N)

K = 200/3276
K = .06105

There is one addition factor. Since the lowest value read
is 1 V, this offset is subtracted from all readings. A 1 V
offset is 1/5 of 4095 counts, or 819. The program line
then becomes:

200 A=.06105*(AIN(N)-819)

Note that if the current loop line breaks, a negative value
is returned.

AMPLIFIERS

Two operational amplifiers are available to signal
condition inputs. Each amplifier is configured as shown
below.

Example 2: You want to measure a 0 to 200 PSI
pressure transducer with a 0 to + 5V output. Divide 200
by 4095 to obtain the constant K.

K = 200 / 4095
K = .0488

The code can then look like:

1000 B = .0488 * AIN(0)

Measuring 4-20 mA current loops

Current loops is a convenient way to transmit a value
and still assure the integrity of the signal. If the line
should break, a 0 volt (or nearly so) is returned.

A 4-20 ma current loop is converted to 1 - 5V by placing
a 250 ohm resistor across the input of the chan nel to
ground.

Current loop r eadings ar e conver ted to engineer ing units
by performing scaling as described earlier. Since the
measur ement r ange is 1 to 5V , the count ran ge is
reduced by 20% to 3276.

If pressure were measured:

Figure 10-2 Amplifier circuit

Amplifiers are accessed through header connector H1.
Pin out is as follows:

H1 pin Function

1 Temperature output from U14
2 To channel 0 analog input
3 Non-inverting input, amplifier A
4 Output from amplifier A
5 Inverting input, amplifier A
6 Approximately + 7V supply (5 ma

maximum)
7 Ground
8 Ground
9 Non-inverting input, amplifier B
10 Approximately -7V supply (5 ma

maximum)
11 Inverting input, amplifier A
12 Output from amplifier A

Page 10-6 RPC-320

ANALOG INPUT SECTION 10

Voltage outputs from pins 6 and 10 are generated by the
RS-232 chip U8. Both of these voltages go through a
100 ohm resistor to H1-10 and H1-6. Pin 10 goes to 0
volts when operating the board in IDLE modes 1 or 2.
Pin 6 goes to about + 5 volts. These voltages may be
used to supply power to very low power amplifier s.

CALIBRATION

The A/D comes factory calibrated for a 0 to 5V inpu t.
This range is changed by adjusting R17. You can adjust
the range to 5.12V. This is useful when the input is 0 ­5V and you want to know when the input is over-range.

To calibrate or adjust the voltage reference:

1. Connect the voltmeter ground to a GND point
on the Analog IN terminal strip. Make sure
there are no other connections to the analog
ground.

2. Connect the voltmeter ' + ' lead to U14, pin 6.

3. Adjust R5 for 5.00 VDC or other voltage as
desired. Do not exceed 5.2 or go below 4. 8
volts.

COMMANDS

The following RPBASIC-52 com mands are used for
analog I/O. Mor e inform ation is found in the appendix
of this manual.

Command Function

AIN(n) Returns analog value.
CONFIG AIN (n) Configures analog input

channels

Page 10-7 RPC-320

WATCHDOG TIMER SECTION 11

DESCRIPTION

The watchdog timer is used to reset the RPC-320 if the
program or CPU "crashes" . The time r is built into the
80C320 CPU. Timed access requirem ents built into the
CPU make it high ly unlikely an er rant processor would
cancel a watchdog timer.

The watchdog should not be used in loops which do not
end quickly or are of indeterminate duration unless a
WDOG command is included. An example of an
indeterminate loop is one that waits for a port condition
to change.

The timer is set by executing a WDOG n command. n is
0, 1, or 2. 0 turns off the timer. 1 sets the watch dog
time to 380 ms while 2 sets it to 2.8 seconds. Executing
WDOG by itself resets the timer. WD OG must be
executed periodically to prevent a reset.

When the watchdog times out, a softwar e reset is
perfor med. The effect is lines at J3 do not change as in
a power-up or hardware reset. Lines at P6, display, and
keypad port are reset to power -up conditions.

EXTERNAL RESET

The card is reset externally by momentarily shorting
W10[1-2]. Reset is also achiev ed by shor ting W10-2 to
ground. Maintain this short for at least 10 ms. The card
will then reset for about 350 ms.

Page 11-1 RPC-320

EXTERNAL INTERRUPT SECTION 12

DESCRIPTION

There are two sources of interrupts the ONITR statement
responds to: Inter nal and exter nal. Exter nal interr upts
are off-card. Internal interrupts are from the counter.

External interrupts are used to "wake-up" the card from
any of the IDLE modes. This feature is useful in power
conserving modes.

Signals to P2-ISOA and P2-ISOB are optically isolated.
P2-INT is a non-isolated, TTL input. Only 1 inter rupt is
selected. Available inte rrup ts are show n in the table
below.

W8 Pin Description

1-2 External TTL level through P2 (INT)

or optically isolated through P2 (ISOA

& ISO B)
3-4 Carry or borr ow pulse from counter
5-6 Carry pulse from counter
7-8 Borrow pulse from counter

INTERRUPT CHARACTERISTICS

Interrupts are negative going edge sensitive. This means
an interrupt is detected when P2-INT goes low or when a
voltage is applied to P2-ISOA and ISOB for at least 10
micro-seconds. To detect a subsequent interrupt, the
line must go high at P2-INT or voltage removed at P2­ISOA/B for at least 10 micro-seconds.

The status of the interrupt or ISOA/B line is read using
the following statement:

100 A = LINE(8)

When A = 1, P 2-INT is high or no v oltage is applied to
ISOA/B.

The P2-INT goes to the output from the opto-isolator I1.
Since this line goes to a 10K ohm pull-up resistor,

additional devices can generate an interrupt only if they
are "wired-or".

PROGRAM EXAMPLE

ONINT selection is through jumper W8. This chapter
describes using exter nal inter rupts P 2-INT or ISOA/B.
When a counter is used, then external interrupts may not
be used. See Chapter 14, Counter Inputs for more
information.

External interrupt at P2-INT is TTL level compatible.
Bringing this line low generates an interrupt when
ONITR is enabled.

OPTICALLY ISOLATED INTERRUPT

ISOA and ISOB provide an isolated, higher voltage
input. Neither input is connected to ground or + 5V and
is isolated to the card by at least 500 volts.

An external voltage of at least 3.5 volts, any polarity,
will generate an interrupt. Higher voltages may be used
provided a series resistor is in line to the supply. Use
the following formula to determine the series resistor
needed.

Rs = (Vi - 6) / .005

The following program enables interrupts and goes to a
routine to service it. Jumper W8[1-2] and bring P2-INT
to ground to see this example work.

10 ONITR 500
30 GOTO 30

500 PRINT "Got Interrupt"
510 RETI

Line 510 is necessary to re-enable all interrupts. If th is
line is not executed, but a RETURN is used, then
ONT ICK is also d isabled. If your pr ogram requir ements
require disabling all interrupts for a time, then the RETI
statement can be executed within any subroutine to re-

Where: Vi = input voltage

No series resistor is needed when Rs is negative.

Page 12-1 RPC-320

EXTERNAL INTERRUPT SECTION 12

Figure 12-1 Optically isolated and TTL interrup ts

enable interrupts.

Page 12-2 RPC-320

MULTI-MODE COUNTER SECTION 13

DESCRIPTION

The 24 bit multimode counter is capable of up/down,
binary, divide-by-n, and quadrature inputs. Count
frequency is DC to 20 Mhz. The R PC-320 uses an LSI
Computer Systems LS7166. Its data sheet is foun d in

Appendix C.

The COUNT function and statement are used to read
from and write to the counter . L INE B is used to
program the chip for various op erating mode s.

An interrupt, using ONITR, may be detected on a carry,
borrow, or either event. The eve nt is jumper selectable
through W8. When the counter is used, external
interrupts (see Chapter 12) may not be used.

W8 Pin Description

1-2 External TTL level through P2-6 or

optically isolated through P3
3-4 Carry or borrow pulse from counter
5-6 Carry pulse from counter
7-8 Borrow pulse from counter

Specifically, RPBASIC writes a 2 to the MCR (M aster
Control Register), reads the 3 counter bytes from the OL
(Output latch), and converts it to the proper internal
BASIC format.

100 A = COUNT(0)

COUNT statement writes a 24 bit number to the PR
(Preset register) only. Its syntax is:

200 COUNT 0, D

To transfer this number to the counter, execute the
following in the program:

LINEB 6,1,8

The counter number is always 0 on the RPC -320.

LINEB is used to access specific registers within the
chip. Accessing control and status registers is shown
below. Counter bank is 6.

100 A = LINEB(6,1) : REM Read OSR
200 LINEB6,1,X

Signals connect to the counter via P2. Use the following
table to determine signal input to the LS7166.

P2 Function
Name

A IN Count inp ut A
B IN Count input B
GND Ground
LOAD Load counter/latch (LCTR/LLTC)
GATE Gate/reset counter (ABGT/RCTR)

Input lines (A IN), (B IN), LOAD, and GATE are
pulled to + 5V through a 10K resistor.

PROGRAMMING

The LS7166 is capable of several operating modes, all of
which are not discussed here. See Appendix C for this
chips operating modes. What are shown are examples of
how to program this chip.

NOTE: Be sure to initialize the counter chip before

using COU NT com mands. Failure to do so
returns meaningless results.

Line 200 writes to OCCR, ICR, QR, MCR, and ICR
registers. W hich registe r selected is determ ined by bits
6 and 7 in the byte written to the chip.

Program examples

This code resets the counter and enables the inputs. The
count is printed once a second. To see the count change,
momentarily bring "A IN" or "B IN" on P2 to ground.
When "B IN" is grounded, the count decrem ents.

10 LINEB6,1,32
20 LINEB6,1,64+8
30 ONTICK 1,500
40 GOTO 40
500 PRINT COUNT(0)
510 RETI

Line 20 can be shortened somewhat. 64 selects the ICR
(Input control register ) and 8 enab les inputs. 72 could
have been used.

The COUNT function returns the current counter value.

Page 13-1 RPC-320

MULTI-MODE COUNTER SECTION 13

The following program example returns a frequency.
Input signal is at "A IN".

100 LINEB 6,1,32
110 LINEB 6,1,72 : REM enable inputs
120 ONTICK 1,500
130 IDLE
140 GOTO 130
500 A=COUNT(0) : REM get count
510 C=A-B : REM figure change from last time
520 PRINT "Frequency = ",A
530 B=A
530 RETI

The first frequency read will always be a bit off. This is
because of the time required to initialize ONTICK.
Subsequent readings are more accurate.

Accuracy is increased by stretching readings to every 10
seconds. This is neces sary w hen higher accura cy is
needed.

Other factors affecting accurate readings in this program
include serial communications and ONITR statement. If
ONITR is in process, ONTICK is delayed until ONITR
is finished.

COMMANDS

The table below lists commands used with the counter.

Command Function

COU NT(0) Returns value in counter
COUNT 0,n Writes value to counter

The problem with this routine is periodically, a large
negative number is returned. This is because the
multimode counter has rolled over. This is corrected by
periodically reseting the CNTR or transfer ring P R to
CNTR. Refer to the data sheet, Appendix A for counter
operating modes.

This program sets up the LS7166 to cause an interrupt
when a pr eset numb er of cou nts is reach ed. W8[7-8] is
jumpered to interrupt on a borrow.

10 LINEB 6,1,132
20 COUNT 0,1000 : REM write to CNTR
30 LINEB 6,1,8 : REM transfer PR to CNTR

40 LINEB 6,1,72 : REM enable A/B counters
50 ONITR 500
100 PRINT COUNT(0) : REM print progress
110 GOTO 100

500 PRINT "In Interrupt"
510 RETI

Line 10 sets OCCR to divide by N. Line 50 enables
interrupts. Line 100 prints the counter. When pulses
are applied to the A input, the count will go down. When
1000 pulses are detected at A input, the message in line
500 is printed.

Page 13-2 RPC-320

POWER MANAGEMENT SECTION 14

DESCRIPTION

There are three power management modes. Each mode
affects the way RPBASIC operates. The IDLE
command is used to control how the card operates

Default mode is full power. All commands, timers, and
interrupts function. IDLE command is not used.

There are a number of ways to exit the IDLE mode in
conjunction with ONITR. Refer to Chapter 12, External
Interrupt and Chapter 13, Multi-mode Counter for ways
to generate interr upts. IDLE 2 is restricted on the type
of interrupt. The signal at P2-INT must return to a high
state before the next IDLE 2 command is executed. (P2­INT is also controlled by the multi-mode counter and
optically isolated interrupt, described in Chapter 12 and

13.) If it does not go high, IDLE 2 mode will exit in
approximately 3 ms. This is due to a characteristic of
the A6 mask revision in the Dallas 80C320 CPU. A
general rule is to keep the negative pulse at P2-INT
greater than 50 ns but less than 3 ms.

IDLE or IDLE 0 waits until an ONTICK or ONITR
interrupt occurs. Serial I/O operates norm ally. U se this
comm and when you wan t your pr ogram to "hang out"
until something happens. The RPC-320 operates under
full power.

IDLE 1 reduces power by 30% . H ere the C PU " shuts
down" but the internal timers are still operating.
ONTICK and ONITR will cause the card to come out of
power down m ode. Howe ver, the RS-232 serial ports
are disabled. Characters in the transmitter buffer are not
sent out and incoming characters are ignored.

IDLE 2 is the lowest power mode. The CPU, internal
timers, ser ial ports, and oscillator are turned off. Only
interrupts responding to ONITR wake up the processor.
Current consumption is less than 5 ma with no signals
going into or coming from the RPC -320.

IDLE 2 also has a number of operating restrictions.

This mode shuts dow n the RS-232 rece iver/dr iver IC, so
no characters can come in or go out. T his IC also
supplies current for the amplifiers and analog to digital
converter. Do not apply negative voltages to the analog
input in this mode. The tick timer is shut off. However,
the real tim e clock m odule, if installed, continues to
operate.

NOTE: The RS-232 receiver is shut down in IDLE

modes 1 and 2. Any characters sent to the
RPC-320 during this time are ignored or

grossly distorted.

NOTE: Delay printing out the RS-232 ports for at least

20 ms (20 instructions) after exiting IDLE 1 or
IDLE 2. These chips generate RS-232 voltages
and require a "power up" time. Failure to do
so could result in garbled characters.

NOTE: The < Ctl> -C break character is not

recognized in any of the IDLE modes.
Normally this is not a problem except during
program deve lopment. If the program is
executing an IDLE statement and it won' t
respond to any interrupts, pressing the reset
button is the only way to exit.

Exit IDLE 2 by applying a low going pulse at the INT
input at P2. The pulse width should be 50 ns minimum.
The other IDLE modes require a pulse width of at least
1 micro-second. Optical interrupt ISOA/B may also be
used to exit any of the IDLE modes. The pulse width
needs to be at least 10 micro-seconds.

FURTHER POWER REDUCTION

Some applications require the least amount of power
possible. You m ay rem ove cer tain IC' s from the card to
do this. The table below lists the IC 'U' number,
approximate current consumption (in shutdown and run
mode), and function.

Un Current Function

Run Shutdown

U9 10 mA 400 uA RS-485 interface

U14 100 uA 1.2 ma Reference for U 15,

temperature reference.

U15 5 ma 10 uA Analog to digital

converter

U11 10 mA 1 ua Digital I/O at J3

U17 10 mA 1 ua Display output, keypad

scanner.

U8 30 mA 10 uA RS-232 driver/receiver,

power supply for analog
to digital converter,
amplifiers

Page 14-1 RPC-320

POWER MANAGEMENT SECTION 14

Currents are maximum and minimum as specified by the
manufacturer. Min-max curr ent ranges "guaranteed" by
the device manufacturer have a tremendous range, often
by a factor of 10 or m ore. Current above is “typical”.

Some current consumption is difficult to determine.
Digital outputs, for example, will draw virtually no
current under no load conditions, but can supply 15 ma
to each output if required. Therefore, inputs and outpu ts
connected to the card will affect its current consumption.
Some chips, such as U9, will not draw much current
unless there is activity on the RS-485 port.

Board current consumption may be affected by the
setting of jumper W7. T his jumper determ ines if inputs
at J3 are pulled up or down. When set to pull up inputs,
each line forced low increases current consumption by
50 uA. If all inputs are tied to + 5V or ground,
removing jumper W7 may dr aw less cur rent.

The application program IC in U6 may be changed to a
29C040. This 512K byte memory draws 200 uA less
current than a 32K byte one.

Any contr ol line from P2 to gr ound dra ws 500 uA due to
the 10K pull-ups. Lines at P6 are pulled to + 5V
through a 10K resistor. Each low line draws 500 uA.

The contrast adjustment (R18) can be removed or
adjusted for minimum cur rent.

Program Examp le

This example makes the RPC-320 go into its lowest
power mode.

10 ONITR 500
.
. other code
.
100 IDLE 2
200 GOTO 100
500 PRINT "In interrupt"
510 RETI

Page 14-2 RPC-320

TECHNICAL INFORMATION SECTION 15

ELECTRICAL SPECIFICATIONS

CPU

80C320, 22.1184 Mhz clock

Memory

RPBASIC-52, 32K ROM, jumperable for 64K.
Type: 27C256 Access time: 80 ns or faster.

Program ming and data is 32K or 128K RAM standard,
512K Optional.

RAM optionally battery backed up. Battery life is 5-10
years depending upon RAM size, type, and oper ating
temperature and time.

Maximum BASIC program is 62K

Battery backed using DS1216DM , w hich also acts as a
real time clock. Can also use DS1213C or D to battery
back ram.

Digital I/O

The RPC -320 has 34 digital I/O lines. 24 are from J3,
which is a general pur pose por t.

The specifications below are for digital I/O at P6 and J3
except for the eight high current lines at J3.

Drive current 2.5 ma m aximum per line,

sink or source. TTL
compatible.

Output low voltage 0.45V m ax at 2.5 mA , 1V

max at 15 mA for opto rack.

Output high volts 2.4V minimum, sink or source

at rated current.

All digital input lines are TTL compatible.

High cu rrent ou tput at J3

8 of the 24 lines can drive up to 500 ma at 50V. Refer
to CHAPTER 6, D IGITAL AND OPTO PORTS for
limitations.

High current output at L8

L8 sinks up to 2 amperes at 50 Volts. Sw itching is
through a "zero" ohm FE T switch.

Opto isolated input ISOA/ISOB

Isolated voltages to 250 volts peak may be applied to this
input. A series resistor is necessary for voltages above
12V.

Keypad input

10 lines accept a 16 position matrix keypad. Scanning
and debounce performed in RPBASIC-52.

Display output

14 digital and 6 power and ground lines used to control
LCD, VF , and LC D graphics displays. Displays
supported in RPBASIC-52.

Serial ports

Two RS-232D serial ports. All have RxD, TxD , and
CTS lines. COM 0 has only these lines. COM1 also has
RTS. COM 1 configurable to RS-232 or RS-422/485.
Termination network for RS-422/485 available. Baud
rates from 300 to 38.4K are pr ogram mable. Length
fixed at 8 bits, no parity, 1 start and stop bit.

EPROM and programmer

Accepts 29C256, 29C010, 29C040 or equivalent flash
EPROM from Atmel.
Size: 32K (29C256), 128K(29C010), 512K(29C040)

Calendar/Clock

Optional DS-1216DM installed in socket U5.
Accur acy to 1 minute/m onth
Supported by RPBASIC
Expected life 3 to 5 years depending upon RAM size
installed, temperature, and operating time.

Watchdog timer, reset

Watch dog timer resets CPU when enabled.
Time between resets is 380 ms or 2.8 seconds
Push button reset. External reset through W10.

Power requireme nts

+ 5 ±5% at 95 ma operating.
Current consumption is less than 5 ma in IDLE 2 mode,
all components installed.
Current is less than 1 ma when analog and RS-485 chips
(U14, 15,16, and 9) are removed.
RS-232 voltages generated on card.
Current consumption does not include any opto-modules
or other accessories.

Page 15-1 RPC-320

TECHNICAL INFORMATION SECTION 15

MEMORY AND I/O BANK MAP

Memory

Description Address
RPBASIC-52, U4 0000H - 7FFFH
RAM, U5, 32K 00000H - 07FFFH

128K 00000H - 1FFFFH

512K 00000H - 7FFFFH

I/O Bank

RAM (U5) 0
EPROM (U6) 1
not used 2
Digital I/O (U11)(J3) 3
Display & keypad (U17) 4
Control & L0-L8 (U19) 5
Counter (U13) 6
not used 7

MECHANICAL SPECIFICATIONS

Size

4.6" x 7.0"

4 mounting holes are 0.250 x 0.250 inches from each
edge. Mounting holes are 0.124 inch in diameter.
Board thickness: 0.062
Board material: FR-4

JUMPER DESCRIPTIONS

A * after a jumper position indicates fa ctory def ault is
jumpered.

Jumper Description

W1[1-2]* RAM size 32K, 128K
W1[2-3] RAM size 128K

W3[1-3],[2-4] 29C040 Flash
W3[3-5],[2-4] 29C010 Flash
W3[3-5],[4-6] 29C256 Flash

W2[1-3],[2-4] EPROM selected
W2[3-5],[4-6]* Flash EPROM selected

W4[1-2] COM 1 RS-485 input
W4[2-3]* COM 1 RS-232 input

W5[1-2]* RS-485 terminator
W6[1-2]* RS-485 terminator

W7[1-2]* J3 resistors pulled up
W7[2-3] J3 resistors pulled down

W8[1-2] External or isolated interrupt
W8[3-4] Counter carry or borrow interrupt
W8[5-6] Counter carry interrupt
W8[7-8] Counter borrow interrupt

Page 15-2 RPC-320

W9[1-2]* Do not autorun
W9[no jumper] Autorun on reset

W10[1-2] External reset input.