PET index - hardware projects
(C) 1998-2020 André Fachat
This page contains links to some hardware projects around the PET machines.
- 2023-07-23 Added links to the Micro-PET and Ultimate PET projects.
- 2020-10-29 Added links to Adrian's RESET button project
- 2020-05-02 Added links to Tynemouth's PET keyboard projects and the sd2pet drive.
- 2018-04-01 Added a link to Steve's overview on video boards for the PET
- 2017-10-15 Added the page for Steve's 40/80 column switcher.
- 2017-09-29 Added the page for the multi-editor ROM.
- 2017-08-29 Added the RS232 section.
- 2015-09-20 Added the High-Resolution Graphics extension.
- 2014-12-08 Added the 40-column conversion.
- 2014-08-11 Added new PET video mixer link, add VGA output
- 2013-12-27 Added the SuperPET OS/9 link
- 2013-05-02 Added the Colour PET
- 2013-04-13 Added a custom RAM disk - "RAM Drive 2008".
- 2011-05-01 Added Nils Eilers' custom charactor ROM extension and the PET-SID extension.
Table of content
Whatever you do with the information in these pages or on the linked pages, I am not responsible for any damage you have for using this information. The information herein is provided AS-IS and there is no warranty whatsoever!
This section contains projects related to PET peripherals, mostly IEEE488 related.
- SD2PET
- A new SD-card based storage solution for the Commodore PET.
- CBM-HD
- Ruud Baltissen has made a project to emulate Commodore IEEE488 disk drives using a PC and some hardware.
- LPTIEC and other IEEE488 stuff
- As I have used the IEEE488 bus to connect (almost) all my Commodore equipment, even with my Atari ST and later the PC (as harddrive) I have created a page for it. It contains an IEEE488 interface for the PC to emulate IEEE488 disk drives (using VICE drive code :-), a System to have the PET access serial IEC disk drives, and IEEE488 interfaces for the C64, VIC20 and the VC1541.
- The transfer section of the CBM archive
- Contains a lot of transfer utilities to copy files from the PC to the PET and back.
- Flash Attack cable and sound
- This page contains the description of the "Flash Attack" cable, as well as a PET sound interface.
- The PET library, olcomputers.net, and d'asaro designs (formerly known as 6540rom.com) have circuits for composite video output.
- One of the deficiencies of the PET is that it has no composite video
output to connect normal monitors to it. These links show two circuits
(PET library from "THE PET REVEALED" by Nick Hampshire, p117f, 1979, whereas
oldcomputers.net claims their circuit is untested). Another sample
circuit (well, some resitors basically...) for a 6545 CRTC can be found in my CS/A65 computer.
I have now updated the VDC page to include schematics and boards for adapted versions of the abovementioned two composite video circuits to work with my CS/A computer (which comes close to the PET in this respect).
Hervé from the cbm-hackers list tells how to get video output on a VGA adapter:
"Simply take the schematics from 6540rom.com [ed: now d'asaro designs] and omit all resistors/capacitors that are 100% unneeded in this purpose (directly connect pin 6 of the 74LS02 to the PET's video connector). Take the [VGA] color signal at pin 10 of the 74LS02 and synchro from pin 4. You can add a decoupling capacitor between pins 7 & 14 of the 74LS02 but that is [] not necessary." - CBM RAM-Drive 2008, a RAM disk extension for the 8296 (in German)
- A small hardware RAM disk extension with schematics and a DOS program for it.
Keyboards
This section describes two PET keyboard projects
- A PET keyboard replacement
- Commodore PET replacement keyboard by Tynemouth Software LLP
- USB adapter
- An adapter to use the PET keyboards as USB keyboard on a PC.
This section describes extensions for the graphics generation and character generator ROM
Please note that Steve Gray has compiled an even more extensive list of graphics (and sound) adapter boards at his PET graphics page.
High-Resolution Extension (HRE)
An AtMega-based graphics processor connected to the PET, overlaying the original screen with its own graphics output, on the original CRT!
Colour PET
Steve Gray has announced this brand new project: add colour to your PET! It takes an interesting approach - it converts an 80 column PET back into a 40 column one and uses the extra byte fetched to achieve 80 columns as colour information instead! What's much more astounding is that it only takes two extra chips! The pictures on the link below show that the timing still needs to be improved though (as of May 2013) - the colour does not change exactly on the character borders. But I am confident that this will be fixed.
Character generator RAM
Nils Eilers has managed to replace the - normally fixed - character ROM of the PET with a dual-port RAM card! It is written by mapping the character generator into a PET extension ROM area (switchable). With this you can dynamically change the character set displayed on the screen! Great work!
30 screen lines on a 8296
The 8296 has a screen memory larger than the others due to its 128k memory. So Edilbert has created a configuration and ROM to use the extra memory as additional screen lines!
40/80 column switcher and Multi-Editor ROM board
The Editor ROM is one of the few ROMs that actually change between (some) PETs besides the standard BASIC versions, as it has to support keyboard mapping, different screen timings for different screens, and so on. So for example there is a BASIC 4 editor that still supports the 9" screens without CRTC, to provide an upgrade path. And also we have Steve's Colour PET project from above! So the natural next step for Steve was to create a board to switch editor ROMs easily - see the link for more detail!
Steve has also built a 40/80 column switcher board, that is available separately or combined with the multi-editor board.
The PET does not have RS232 routines in the kernal as the C64 etc have, but could be made to talk RS232 as well...:
Terminal programs in the Transactor Magazine
Transactor Magazine Volume 3 Issue 06 has two terminal programs to type in, with description of the userport interface.
Term in action
Here is a description of how to connect a PET to a Mac using a simple RS232 userport interface and a terminal program.
Lemon64 forum
This forum thread has a number of links and information about RS232 projects, for example to McTerm.
This section contains projects that relate more to the PET itself
- Ultimate-PET
- The beginning of a new series of PET re-creations, based on Micro-PET technology, but with added color capabilities, and expansion slots.
- Micro-PET
- A Commodore PET re-creation on a single Euro-PCB, with a real 6502-type processor (the WDC 65816), up to 12MHz speed, VGA graphics, and USB, Ethernet and SD-Card interfaces
- 40 column conversion of a 8032 universal board
- This blog post describes the conversion of an 8032 universal board to a 40 column system. Some connections need to be changed, and even some chips removed - but the board is prepared for it.
- PET816
- A CPU replacement for the PET that allows it to run at up to 10MHz!
- CS/A65
- This computer system is a modular system with an MMU and other nice features. One feature is the 95% PET compatibility. It actually runs a 3032 PET emulator - which is a slightly patched up copy of the PET ROM (the only difference is the CRTC uses real columns even in 80 col mode, and some IEEE488 lines are swapped around). I plan on building an adapter to use the CS/A65 I/O cards in a PET computer.
- Build your own Fat40
- This project consists of three specific boards for the CS/A65 computer that together can make up a PET 4032.
- PET RAM - a universal 6502 RAM/ROM expansion
- This is a universal PET RAM/Flash ROM expansion with schematics and board diagrams in Eagle(tm) format.
- PET-REU
- This is a RAM expansion unit for the PET, using the (in old boards) unused $8800-$8fff memory area.
- Fitting 8250LP in the high-profile CBM-II case
- A description how to fit the 8250LP disk drive into a high-profile CBM-II case - which is very similar to the 8296 case. So this might be as model to fit a 8250LP into a 8296 case to make a 8296D
- Adding an MMU to a SuperPET and run OS/9
- A description of the MMU fitted under the 6809 of the SuperPET to be able to run OS/9 on it! Mike Naberezny's site even has permission to redistribute OS/9 for that machine!
- Properly adding a RESET button
- Adrian from Adrian's Digital Basement shows how to properly add a RESET switch.
This section contains other 6502-related links, that are less PET-related.
Note: schematics and chip data are linked from the links page
- 6502.org with a host of 6502-related stuff and original host of the PET index.
- Ruud Baltissen not only has the CBM-HD, but other Commodore hardware and software projects as well.
- Peripherals info from the PETFAQ, includes for example how to add a Joystick.
- cbmhardware.de has some german info.
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Last modified: 2023-07-23