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Focal-65 V3D for TIM and KIM-1

Focal on the 6502, a page on this small language, originating for Digital Equipment.
A small interpreter (about 5K) for a convenient interpreted language. Floating point 9 digit accuracy. At least two versions were distributed around 1977, one by Aresco, called “Focal V3D” and another by the Program Exchange as representative of the Denver 6502 Group, often called “Focal-65E”

Latest addition is a reconstruction of the source, by Wayne Wall of the Denver 6502 Group in 1977, of Focal V3D for the TIM to binary, and a port to the KIM-1.
Based upon a listing of the TIM Focal-65 from 1977 and a Focal-65 User manual, repaired and cleaned up.
And that enabled the reconstruction of the soource Focal-65 V3D as distributed by Aresco!

Read all about Focal-65 here!

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Focal-65 V3D for TIM and KIM-1

Focal on the 6502, a page on this small language, originating for Digital Equipment.
A small interpreter (about 5K) for a convenient interpreted language. Floating point 9 digit accuracy. At least two versions were distributed around 1977, one by Aresco, called “Focal V3D” and another by the Program Exchange as representative of the Denver 6502 Group, “Focal-65″ or FCl_65” or “FCL-65E”

Information from the German 1981 article in MC Magazine, see the articles, indicates the existence and sale of Focal versions by the 6502 Program Exchange:

  • FCL-65 and FCL-65E with Mini userguide
  • My version from Aresco Focal V3D, 1-oct-1977 binary and userguide
  • Focal V3D for TIM, listing known and available on this page
  • Focal-65 V3E 1-oct-1979, Apple II, source listing known at MC Magazine in 1981
  • V4 for Apple, listing known and in possession of Wayne Wall, not public available

I suppose this list is incomplete, other versions may have existed. None but my binary of Aresco Focal-3D, the Aresco V3D Userguide, a User Guide by the Denver 6502 group and a listing of Focal-65 V3D for the TIM survived and is available.

Latest addition to this page is a reconstruction of the sources, of Focal V3D for the TIM to binary, and a port to the KIM-1. Also the Aresco version source is reconstructed and identical to the tape dump of 1978.

On this page you will find:

  1. My experience with Focal-65 as started in 1979
  2. Reference material: User manuals, listings
  3. Magazine articles about Focal-65
  4. Reconstructed sources of Focal-65 for TIM and KIM-1
  5. Reconstructed source of Focal-65 for the KIM-1 Aresco version
  6. On the origin of Focal-65

My experience with Focal-65 started in 1979

In 1979 my good friend Anton Muller, at a meeting of our Dutch 6502 KIM Club, surprised me with a package Anton had imported from the U.S.A. : Focal V3d by Aresco.
The package came with a cassette tape and a user manual. We installed it on the KIM-1 and played with it. Impressive what was done in about 5K!
Floating point, string handling, a trick to suppress the hardware echo of TTY input.
After an article in our club magazine more members of the club became Focal-65 users and published articles about it.

This version of Focal-65 has survived. I have dumped a working version from cassette in 2004 (not the original alas, but a working copy with a bit too much) and scanned the user manual.
Manual and binary version have been available on this website now several years. Also I added DEC Focal manuals, Digital Equipment Corp. developed and sold Focal as a product for the PDP computers. In the KIM/6502 User notes articles were published on making Focal even more interesting, also published here.

When the KIM Simulator became usable, I tested Focal and saw that suppressing the TTY echo worked, but the wait for keyboard input loop preceding the read character routine did not. So I added a setting to let Focal-65 survive that loop. So Focal-65, Aresco version, runs unaltered on the KIM-1 Simulator!

The FOCAL programming language

In 2023 a source listing appeared, thanks to Paul Birkel, of Focal-65, programmed by Wayne Wall and friends in 1977. Target system is a TIM such as Jolt or Superjolt. I typed in that listing exactly with modern assembler syntax and made that version operational.
Here I present several reconstructed versions, for TIM (653-004) such as Jolt and KIM-1 based systems.
– A TIM/Jolt/Superjolt system needs minimum 8K RAM in lower memory.
– The KIM-1 needs memory, minimum 8K, from $2000 and up.
See below for the TIM version and a port to KIM-1. These are 90% identical to the Focal-65 V3D Aresco version, so that was the start to recreate that source too .


Reference material for download

First some downloadable reference material.

DEC-08-AJAB-D PDP-8-I FOCAL Programming Manual.
Focal by DEC is the beginning of all Focal implementations. A typical DEC manual, easy to read, complete, well organized.
DEC-08-AJBB-DL Advanced FOCAL Technical Specification April 69
This manual is where Wayne Wall got his design. From the flowcharts and labels, similar names and concepts can be found in the Focal-65 source
Focal-65 users guide V3D, by Aresco
Focal-65 Users Guide V3D by the Denver 6502 Group.
Cleaned up version made by me.
TIM Focal-65 V3D source listing
Cleaned up version made by me.

Articles on Focal-65

KIM/6502 User notes
Articles from the magazine, Focal corner

  1. Introduction to FOCAL, 6502 User Notes 12
  2. Improve on echo problems with KIM TTY, 6502 User Notes 13
  3. Make room for enhancements, extend to 8K, User Notes 14
  4. Speed it up, 6502 User Notes 15
  5. Cassette save/write an LED display listing, 6502 User Notes 16

KIM Kenner
Introduction to FOCAL, how to program, Dutch

Compute II
Modify and Move FOCAL 65-E into EPROM, Compute II Issue 3

MC Magazine
German article on Focal-65, has interesting information on versions

Working versions, reconstructed from sources

Denver 6502 Group Focal for TIM

In 2023 a listing of Focal-65, by Wayne Wall, for a Focal-65 version for the TIM, showed up, thanks to Paul Birkel.
A low low quality scan, so I cleaned it up, improved contrast, removed artefacts and cropped it. The result is readable, but not fit for OCR.

TIM Focal-65 V3D source listing
Original printed listing 1977 by Wayne Wall. Cleaned up version.

I typed this source in, exactly as the listing: uppercase, same comments, same line numbers.In this way I honor the original author and also enable checking of the binary result.
I did change the assembler syntax to a modern assembler. The original was written for PAL-65, an assembler by Wayne Wall in PDP macro assembler format.
When it assembled I compared the binary out to the binary in the listing by hand. Of course typos and the curse of direct addressing, the #!, caused some extra work.
The result was a binary with the same length. as shown in the listing.

Then the binary was loaded in my TIM Simulator, with a small external patch for the ‘no echo’ input character routine in the source. The TIM has ‘software echo’ hardcoded in the monitor for reading a character from TTY, so the monitor code is copied with optional echo.
It runs!


Focal-65 for the TIM, here the source as typed in, listing, binaries in Intel hex and Papertape format and the TIM Simulator patch.

Denver 6502 Group Focal for the KIM-1

To illustrate how easy it is to adapt Focal to other 6502 systems, I ported the TIM version to the KIM-1.
Changes required:

  1. Program moved from $1000 to $2000
  2. Replaced the TIM I/O package with a KIM-1 version: IRQ/BRK vector, no echo character input (partly taken from the Aresco disassembly for character output
  3. Further no changes, same line numbers, same size

This version runs fine in the KIM-1 Simulator with the Focal V3D setting.



Focal-65 for the KIM-1, here the source as typed in, ported to KIM-1, listing, binaries in Intel hex and Papertape format

Aresco Focal-65 V3D

Here the original Aresco Focal V3D dump from cassette. Note that the dump contains a bit more than necessary. The zeropage is completely dumped, and filled in by a running Focal session.
It runs on a KIM-1 and on the KIM-1 Simulator with the Settings – Type of Break setting set to Focal V3D.

First attempt to get a source, unfinished, does not assemble, but informative.
Disassembled source by Paul R. Santa-Maria (2004) and Hans Otten (more comments) (2022).

Focal-65 users guide V3D, by Aresco

Reconstructed source of Focal-65 for the KIM-1 Aresco version

With the source of the KIM-1/TIM and the binary of the Aresco version I have since 1978, it was an easy job to reconstruct the source of the Aresco version.
By comparing the binary output of the assembled source and the binary of the tape, differences can be seen and fixed in the source.

The interpreter code is 100% identical to the tape dump (minus the extra unused bytes saved at the end). Zero page is clean.

The code runs in the KIM-1 Simulator with the Focal V3D setting. No surprise, the binary of the tape dump also runs and the binaries of the code are identical.

Focal-65 for the KIM-1, Aresco version, here the source , listing, binaries in Intel hex and Papertape

The history of Focal for the 6502

Excerpt from the history of the Denver 6502 Group.
In 1975, Denver was a hotbed of computer activities. There was a new computer club called the Denver Amateur Computer Society (DACS), and every meeting was packed with radio amateurs and hobbyists anxious to learn about this exciting new technology. DACS was dominated by Intel 8080 based computers, but there were a few people interested in the 6502. Wayne Wall was one of the first to appreciate the power and speed of the 6502, and he decided to form a subgroup of DACS for 6502 users.

Wayne was a genius assembly language and systems programmer who worked at the Colorado School of Mines. He began holding meetings every Tuesday night at the School of Mines Computing Center for anyone interested in the 6502. At first it was called the 6502 sub-group of DACS, but as time went on, it became the 6502 Group.

All told, there were probably about 100 members, but on a typical night, 30 to 40 people would crowd into the meeting room, anxious to hear Wayne’s latest ideas and see his demonstrations. He was famous for his magic shows that invariably consisted of doing something hitherto unimaginable like simulating human speech with 13 bytes of assembly code. Wayne quickly gained the well deserved reputation as a computer wizard.

Most members of the group owned Digital Group systems. The Digital Group was a local company that had a short but spectacular career manufacturing computer kits. They were powerful, easy to assemble and way ahead of their time, with memory-addressable video cards, system monitors and relatively large memory boards. In addition to the Digital Group systems, the group had a scattering of Kim’s, Tim’s, Jolt’s and even a few odd homebrew machines.

At the time, there was virtually no software available for the 6502. All programs had to be tediously hand-assembled and typed into the machines. Wayne decided that his first task was to find a way to deal with this problem.

The School of Mines had a huge black mainframe called a PDP-10, and Wayne wanted to use the power and capabilities of this computer to write 6502 code. The first possibility was to use a FORTAN cross-assembler that was available from MOS Technology, but it was slow and buggy. Instead, Wayne chose to write 6502 macros for the PDP-10’s “PAL” assembler. After a few days work, Wayne had a fast new assembler that he called “PAL-65.” Suddenly we had the ability to write relatively large assembly language programs for the 6502.

Initially, Wayne cranked out a series of assembly language games. The first was a simple text based game where you shot arrows at a mythical beast called a Wumpus. Most of our computers had between 512 and two kilobytes of memory, but as Wayne’s games grew in complexity, we struggled to keep up, spending our nights soldering memory chips onto circuit boards.

Wayne now turned his attention to a high level language. The Intel based microprocessors had a version of BASIC written by Microsoft. Wayne decided that we should have a similar language, and he chose to write a version of the DEC language called FOCAL. Even though it was a relatively obscure language, FOCAL had some subtle advantages over BASIC, the biggest was its ability to evaluate strings as expressions.

Wayne wanted FOCAL to be a group project, and one evening he showed up with a stack of photocopies of the DEC flowcharts for the language. His plan was to assign each section of the chart to one of the 6502 Group members. We were supposed to go home, write 6502 assembly code for the section, and in a few weeks, we’d have an operating version of FOCAL. Unfortunately, Wayne had overestimated our skills. Most of us had been assembling code by hand and had no idea how to work from a flow chart. In the end, Wayne and Bob Ulshafer did most of the coding.

When it was finally finished, FOCAL was a big breakthrough. Suddenly we had a true programming language. Complex new games began to appear on our computers including a version of the famous mainframe game Star Trek, written by Larry Fish. Over the next few weeks Wayne wrote a five-byte floating point package for FOCAL based on a Dr. Dobbs article. With the new floating point power, simulations and mathematical programs sprouted up everywhere.

With thanks to Paul Birkel for the scan of the listing.

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John Bell Engineering catalogs

Thanks to Dallas Shell I have added the 1984 and 1988 catalog to the John Bell Engineering pages.
Also a hand drawn and official circuit diagram of the 82-300 SBC.

LJ Learning EMMA update

I have added a page on LJ Technical Learning’s Digiac line of 6502 systems.

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Digiac 6502 systems

Under the brand name Digiac LJ Learning made 6502 based systems.

On this page a collection of documents and images on DigiaC DT100, Digiac 2000, MAC III boards.


Brochure Digiac 2000
6502 Instruction Set Reference Manual Mp622a
6502 Microprocessor Applications Curriculum Manual MP615_a
6502 Microprocessor Applications Solutions MP616_A
D3000_8_1_ES (P6214)
DT100 Instructors Solutions Mp628_a
DT100 Text Book Mp626_a
MACIII User Manual Mp600_c

EMMA

The EMMA and EMMA II SBC’s were produced by LJ Electronics Ltd, Norwich, a company established in 1979 to market training technology to colleges, schools and universities. The company behind LG Electronics still exists but is now known as LJ Create, also carrying the USA based brand Digiac.

Here you find information on:
EMMA
EMMA II
EMMA emulator by Colin Grey

Emma

Emma, full name MS1 Emma Microcomputer, is a rudimentary 8-bit 6502 processor board, quite similar to the KIM-1 family, with attached hex-input keypad and 7-segment display that was marketed by LJ Electronics in the early eighties. Despite its mere 1K of RAM and 2K monitor in EPROM, it was deemed suitable for driving the Atlas arm. In addition to the processor itself, the Emma range,L.J. Electronics Basic Microprocessor Application System MA02/1, included a large number of sensing, simulation and input-output boards that Emma could be hand-coded to interact with. There was even a mini matrix printer for hard-copy output.
The images below show the Emma processor, keypad and display unit, plus many of the available add-on boards. More complex expansion options included an Eprom programmer and an A4 plotting table. Further capability could be added in the form of the Visa Expansion System – shown above connected to Emma. This added a video interface, 8K of RAM, 8K of BASIC, 6K of assembler and monitor and a full QWERTY keyboard.
EMMA uses a 6502 with a1 MHz crystal, an INS8154 + 74145 RAM I/O IC for 24 keys scanning and 8 seven segment displays, a 6522 VIA for general purpose I/O, 2x 2114 SRAM and a 2716 for the monitor program. A group of CMOS CD4XXX IC’s delivers a Cassette interface

Any additional information, like software, is appreciated!

EMMA manual in PDF format. L.J. Electronics Basic Microprocessor Application System MA02/1, consisting of the MS1 Emma Microcomputer and numerous components, as listed in the MA-02 manual.

Hardware Manual for the EMMA  – 46 pages plus large appendices If ou have it, please help me scan and publish it! I only have three pages as seen in a recent ebay listing:




Emma computer with Visa upgrade, controlling an early Atlas robot arm

Emma II

Emma II was a more compact and complete successor of the Emma. Quite similar, but the keyboard encoding is now done with a 6821 PIA. A VIA 6522 is also present and the usual hex keybaord and seven segment display.

Emma II is well documented (thanks John Evans)

EMMA II Technical manual in PDF format, including schematics and monitor source, 115 pages.
EMMA II User manual in PDF format, 109 pages full of experiments.

Token-ring with EMMA II
Running lights with EMMA II
Flashing text with EMMA II
EMMA II EPROM bin
EMMA II EPROM hex
EMMA II EPROM memory expansion bin
EMMA II EPROM memory expansion hex

Memory Expansion module with RAM ROM and EPROM Programmer (Photo John Evans)

EMMA emulator by Colin Grey

This is a 6502 simulator. It is loosely based on the LJ Technical Systems EMMA board. Although quite useful it is not a full implementation. Download here.

End of year updates to my programs

I have made some small updates to four of my programs.
Updates are bugfixes, cosmetic changes to also to let Raspberry Pi OS versions work, a nicer looking Windows setup and in general bringing all the programs to the same level.

Convert 8 bits hex formats V 2.7
KIM-1 Simulator V 1.3.9
TIM Superjolt Simulator V 0.5
SerialTester V 1.1

Tiny Basic by Tom Pittman

Sources, manuals, articles, patched binaries for KIM-1 and TIM!Tiny Basic for the KIM-1 and the TIM in the SuperjoltTiny Basic interpreter.
Copyright 1976 Itty Bitty Computers, used by permission
On this page information how to run Tiny Basic, by Tom Pittman, for the KIM-1 or a TIM (RRIOT 6530-004) based machine, like Jolt and Superjolt, with 4K RAM at least extra.Any 6502 machine with character I/O can run Tiny Basic, source is available with just a few changes to be made to I/O, memory layout and breaktest.

All tests and binary file manipulation with Tiny Basic have been done with my KIM-1 and TIM Superjolt simulators, and also got an update this week.

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Tiny Basic

Tiny Basic for the KIM-1 and the TIM in the Superjolt

Tiny Basic interpreter Copyright 1976 Itty Bitty Computers, used by permission

Tiny Basic on the Superjolt

On this page information how to run Tiny Basic, by Tom Pittman, for the KIM-1 or a TIM (RRIOT 6530-004) based machine, like Jolt and Superjolt, with 4K RAM at least extra.
Any 6502 machine with character I/O can run Tiny Basic, source is available with just a few changes to be made to I/O, memory layout and breaktest. Note that most of the zeropage is used by Tiny Basic!

All tests and binary file manipulation with Tiny Basic have been done with my KIM-1 and TIM Superjolt simulators.
File conversion between binary and papertape and such is done with the Convert Hex 8 bit formats utility.

On this page you find:

A TIM (6530-004) Superjolt simulator update, also KIM-1 Simulator

A TIM (6530-004) Superjolt Demon simulator.

Version 0.4. TIM Superjolt Simulator V0.4, Tiny Basic working!

Since the TIM Simulator and the KIM-1 Simulator share a lot of code, also the KIM-1 Simulator got an update, to let Tiny Basic work better: V1.3.8 is available.

The bundled Conversion 8 bit hex formats is now at version 2.6.

I have since yesterday a Raspberry Pi 5. Great little machine. Very grown up installation. Lazarus works fine with the usual trick of first the apt install version and then fpcupdeluxe for a newer version.

The TIM and KIM-1 Simulator work fine on the Pi 5, so a Raspberry Pi 5 is now included in the distributions.