Convert to Papertape V2.2

On the Utilities page I have two programs to convert to MOS Technology papertape format: KIMpaper, a command line utility, and ConvertHexFormat, a GUI app.

All in Freepascal/Lazarus source format, and tested on Linux (Raspberry PI OS) and Windows 10 64 bit. So the programs will run everywhere Lazarus is available (MS DOS, WIndows, Linux Mac OS).

KIMPAPER  is written at the time the Micro-KIM appeared. CLI utility.  Supports Binary to/from Papertape.  Still runs fine on all platforms supported by Freepascal (Windows, MS DOS, Linux etc) after a recompilation, source available.

ConvertHexFormat is a more recent GUI utilitilty with many more 8 bit hex formats as input and output.

There were some bugs of course in older versions. V2 added the ability for multipart hex formats, records having a non-consecutive load address. That seems to wok fine since V2.1
In 2.2 a bug in MOS Papertape format for bigger files is fixed, the end-of-file record (record type 00, total line count) had a bug in the checksum calculation. KIMPAPER is and was correct in the calculation.
But in ConvertHexFormat it was wrong (as it still  is in the well known srec utility in the Unix world!).


PC utilities updated

The PC utilities page has seen an update of th4 Conversion hex formats utility.

Programs to manipulate the binary and hex formatted files of interest for SBC owners. Intel hex, MOS papertape, Motorola S-record, binary, hex conversion fort eh 8 bit world.
Runs on Windows, Linux, Mac due to Lazarus and Freepascal. Source included.

Noise fix for Replica Ten

and perhaps other Replica’s with the Propeller IC. Report by Didier.

Didier has 2 replica, the Red one Ten, the older one green, both With a propelle which had the same problem but it occurred rarely

in fact apparently all the Replica 1 with the Propeller IC ten are affected more or less by this problem.


Users have reported every few seconds a “/” appears on their screen followed by a linefeed. This renders any data entry impossible.
The Replica 1 seems to act like an antenna, moving hands above the Replica can trigger it.
The problem is reported by Reactive Micro as Screen Noise Issue.

Fix by Reactive Micro

Try adding a 100k resistor to the USB module as pictured below. And if there is still noise then add a .1uF cap (100nF) to Pin28 of the Propelelr to either Ground or +5v.

As little as 10k can be used for +3.3v pullup, but anything smaller risks damage to the FTDI module. 100k is much safer in all regards. This helps hold the data line high. It seems the RX line is held high by default. And both lines are held high when connected to a USB data port, which is why the noise issue is not seen when connected to a PC. You can connect the resistor most simply to the USB module. Or to the rear of the PCB to pin 39 (Tx) and pin 12 or 32 (+3.3v) of the Propeller.

Fix by Didier

The Reactive Micro fix dows only reduce the noise but does not stop it completely.
But adding two 2 resistors definitively fix the problem.
The real problem is the floating lines STROBE and DA of the Propeller.

To really understand this noise bug you need to check at the same time:
the circuit diagram, the Wozmon initialization, and the Propeller code

the other modification are for a change from a PIA to a PIAT for my 6502 monitor
PIAT (6524) = PIA 6250 + TIMER (as it is mounted with my patch the PIAT replace totally the PIA
without any software change)

2 lines CA and STROBE are input at the same time…
they are acting like an antenna and capturing noise
for example, if I pass my hand 5 cm above the propeller
I start to see:

as if the replica was resetting.

In fact, when the replica received a full buffer of junk it jumps to reset code…
The problem comes from the propeller code…
STROBE is programmed sometimes as input and sometimes as output to permit both the PS/2 and ASCII keyboard
it is possible to fix the propeller code to avoid the parasite but in that case, you lose the ASCII keyboard

To fix that on the back of the board add a resistor of 10K between the STROBE PIN and GND
The same problem occurs for the DA line but it only happens during the time the machine was powered up but not yet reset… the same way a 10K resistor between DA PIN and GND fix the problem

The fix for STROBE and DA is therefore two resistors added on the back of the PIA.


The PockeTerm is a 4″ X 2.5″ single board terminal that uses a VGA monitor and a PS/2 keyboard for its input and output. Dual serial ports gives the user the option of transferring data to/from a PC while still connected to the host device. This terminal was designed to work with vintage computers but is compatible with most systems including Unix and Linux systems. A low cost color choice terminal that has VT-100 compatible commands for controlling cursor and screen functions. Want to program the propeller microcontroller or install an update to the firmware? No problem, just connect the PockeTerm to your PC, run the Propeller Tools software and you can program it from your PC, no expensive Prop Plug required.

The PockeTerm has a full featured screen with Function key status at the bottom of the screen. Click on the image for a full size photograph of the screenshot.

CTRL-F1 Selects Baud Rate
CTRL-F2 Changes text color of the main display section
CTRL-F3 Turns on/off the 2nd serial port that connects to a PC.
CTRL-F4 Force incoming data to 7 bit ASCII. Strips the 8th bit, required for some systems
CTRL=F5 Change cursor type. Choose from underscore, solid block, or none. Also, choose from blinking or not.
CTRL-F6 Add line-feed to carriage returns


Pocketerm Setup and Users Manual 2009
Pocketerm Setup and Users Manual V3 2009
Pocketerm Circuit diagram
Pocketerm Bill Of Materials
Pocketerm Firmware
Pocketerm CD

PS/2 keyboards

I have succesfully assembled the kit, the manual guided me just fine through the steps. Took me just over an hour.
The PockeTerm worked right away. Thanks to mfortuna’s tip, put jumpers in 1&2 and 5&6, and testing is independent of cables and computers to connect.

A standard keyboard with PS/2 worked. What did not work was my mini-USB keyboard (standard PC keyboard without numerical pad, and smaller size, like notebook keyboards) connected via an USB to PS/2 converter. The USB keyboard is ok, works with the PC’s and the Apple 1 kits via the USB-PS/2 dongle. I bought it because the smaller size looks better with the small computers and takes less desk space With the scope I found the PS/2 clock/data line (cant remember which one), to be open, as if nothing connected. So something is missing to make the USB device come alive. I googled around and found this:
In it I saw a schematic how to connect a Parallax mini PS/2 keyboard, and it was different from the PockeTerm PS/2 interface. It has additional 10k pull-ups connected to the PS/2 clock and data. I soldered in the two 10k’s and the mini keyboard came alive!

Program the Propeller Notes by Vince Briel

  1. Go download propeller tools from parallax here:
  2. Install propeller tools
  3. Place the firmware directory from your PockeTerm CD onto your hard drive here:
    C:\program files\parallax inc\propeller tool v1.2.7 (r2)\
  4. Connect your PockeTerm to the RS232 port labled PC and turn on your PockeTerm.
  5. Under the propeller tools program click on the section File and find the firmware directory you just copied onto your hard drive and select the file
  6. Press F11 on your PC keyboard and the propeller tools will compile and attempt to find a Propeller chip connected to a serial port on your PC. If your
    connection is good it will program the RAM first on your Propeller chip then program the EEPROM.

The PockeTerm makes a really good development board for learning how to program the Propeller chip. For more information on programming the Propeller,
please visit the Parallax forums here:
The above steps will program the Propeller with the code that is now resident on the EEPROM onboard the PockeTerm. Change step 3 to the location of the program you wish to insert onto the PockeTerm.

Replica 1 software and hardware articles

A collection of articles and projects around the Replica 1.


REBUS Replica 1 Hardware Extensions
ACIA, Flash, Apple II sound
Ken Wessen
Apple II sound circuit
Replica Quick reference by Jeff Trenter
Krusader Ken Wessen’s assember IDE
Archive with many variants, sources, versions
Krusader 1.2.1 source for use with an ACIA
Applesoft Lite archive
EWoz extended WOZ monitor with hex file upload
Jeff Tranter’s large collection of 6502 articles
Micro-KIM, Replica 1, and much more. A real treasure collection, original here!

EEPROM programmer circuit (as featured on the Multi I/O board)
EEPROM circuit
Here’s a 1 chip EEPROM programmer for somebody wishing to copy their EEPROM or create their own data. In keeping with the replica 1 theme, it is a down and dirty solution requiring few connections. All the connections listed on the EEPROM go to their listed connections. A 74LS00 is all that is required to program an EEPROM.

This attaches to address A000-BFFF and is direct addressing. Simply write to the address to store the data. You should give a slight delay after your write since it takes 200ns to write a byte into an EEPROM. I do a short loop in basic


That does the trick. I tested this circuit out and had 0 errors when writing.

Replica 1 Cassette Interface

In 2007 Vince Briel tried to get a replica of the Cassette board, as designed by Steve Wozniak, operational. Another example of the genius Steve Wozniak, minimal hardware, 256 byte program. Two revisions, he did not have much luck with this. Reports indicate this has to do with insufficient quality of the power supply lines.

Original Apple 1 Cassette Interface Manual
A real userguide as can be found at the site of San Bergmans
Mimeo Cassette Interface and Operations Guide

Archive with disassembly and source files of the Apple 1 Cassette Interface.


Replica 1 Multi I/O Board

The Multi I/O Board, 2007, gives 2 8 bit bi-directional ports with 4 handshaking lines, a 6522 VIA,, a true RS232 serial port, a 6551 ACIA, with speeds up to 19,200 BAUD, and a 8K EEPROM programmer to store data or programs. There is a socket to add your own Speakjet voice chip that works in conjunction with the serial port to make your Replica 1 or Apple 1 speak!
Software included to let the WOZmon operate over serial.

Multi I/O board Setup and users Manual

Replica 1 slot expanders

Three slot expander

Available first in 2006 for the SE and continued to the Plus. One side for the 40 pin connector, the other side a real Apple 1 slot.

Note that sometimes the 40 pin flatcable connection is not reliable and gives CFFA1 I/O errors. A thick extra ground wire between the Replica 1 and the slot expander solves this.

Slot Expander I board manual

One slot expander

A single slot expander, one Apple 1 slot, to be placed upon the 40 pin box connector.

Replica 1 TE

Replica 1 TE improvements (2008)

  • Apple 1 compatible 44 pin slot
  • Apple 1 compatible 44 pin edge connector
  • Bread board area for hobby experiments
  • Elimination of jumpers
  • Improved video display using Parallax Propeller (works with most TV’s and monitors)
  • No need for Apple 1 slot adapter because Apple 1 slot now onboard as well as original replica 1 connector
  • User firmware updates. User can download firmware updates and install. No need to send in for new chips.

The use of the Propeller instead of the ATMega IC’s makes the TE more compact, it handles video and PS/2 interfacing.

Replica 1 TE Setup and users Manual
Replica 1 TE schematic

Replica 1 TE CD


Junior by Philippe Roca

Philippe Roca sent me photos and Gerber PCB files from his Junior system.

From scratch, reading the original Elektor articles, he designed and built a complete Junior system.

Faithfull to the original and with even the ‘problem’ parts such as the 2708 EPROM on the main PCB and the 82S33 PROM on the interface card. For those devices he built programmers!

Still working on building and testing (January 2021), here photos and Gerbers of finished and working cards.


Interface card



Gerbers download

Junior PCB gerber
Display print gerber
Power supply gerber