The Ulti-PET
(C) 2022-2024 André Fachat
The Micro-PET family is a re-incarnation of the Commodore PET computer(s) from the later 1970s. It is re-using various technologies from the Micro-PET, the CS/A computer, and others.
- 2024-10-30 Update on the development status, add link to new video
- 2024-09-21 Update on the development status, presenting Ulti-PET prototypes.
- 2024-02-03 Clarification on the goal of integrating into a single PCB and the components.
- 2023-12-13 Update to 1.3C that is using an FPGA and has many more features, like graphics features, or DAC output via DMA.
- 2023-01-08 The Ultimate PET introduced
After building the Micro-PET I noticed, that for further features, I would have to get larger than a Euro-card. I started working with KiCAD, migrating some of my boards there and continued working on a larger version of the Micro-PET: The Ulti-PET.
Finally, I reached a point where I was confident enough with the technology that I can now present three boards based on that tech:
- The Micro-PET: a PCB that clones a Commodore PET, and adds modern features like SD-Card, USB, DAC audio, Network support, and colour VGA video output
- The Micro-CPU: The CPU and modern tech part of the Micro-PET (SD-Card, USB, DAC audio, Network, VGA video) as CPU for the CS/A bus.
- The Ulti-PET: a Micro-PET-based PCB with many many new features like Dual-SID, I2C, RS232 / TTL UARTs, fast serial IEC, Joysticks,, ...
The main development is happening on github (see link left in the menu).
Status
All three boards have been tested. The Micro-PET and Ultra-CPU boards work. The Ulti-PET board needs some minor adjustments - the 2nd SID was not adressable, Joystick fire buttons did not work, some parts placement issues).
I am currently working on a new revision of the Ulti-PET board, which will be revision 1.2.
Further plans for firmware updates are:
- Store configuration in RTC EEPROM, allow to modify it on the boot screen
- Allow using the (fast) serial IEC bus instead of the parallel bus
- Support USB keyboard and SD-Card in BASIC 2 and maybe BASIC 1 also, and optionally in the unmodified ROMs too
Features
Here is a list of the features:- Ulti-PET features
- Commodore 3032 / 4032 / 8032 / 8296 with options menu to select at boot
- Boot-menu to select different PET versions to run
- 40 col character display
- 80 col character display
- 8296 memory map emulation
- IEEE488 interface (via PETIO board)
- Tape connector (pin, via PETIO board)
- PET graphics keyboard, or alternatively a C64 keyboard
- Improved system design:
- 512k video RAM, 512k fast RAM accessible using banks on the W65816 CPU
- boot from an SPI Flash ROM
- up to 17.5 MHz mode (via configuration register)
- VGA Colour video output (RGBI in 768x576)
- Write protection for the PET ROMs once copied to RAM
- lower 32k RAM mappable from all of the 512k fast RAM
- Improved Video output:
- Multiple colour modes (Colour-PET, C128-VDC-compatible, Multicolour)
- Colour Hires graphics mode
- Sprites
- Modifyable character set
- 40/80 column switchable character width
- Flexible timing, with up to 72 lines and 96 characters per line
- multiple video pages mappable to $8000 video mem address
- Audio output:
- PET beeper :-)
- DMA engine to play audio samples on stereo DAC sound output
- Dual-SID
- Audio mixer and small audio amp (Ulti-PET only)
- Extra I/O features on top (mostly Ulti-PET only)
- Colour-PET compatibility (as defined by Steve Gray's colour-PET project)
- RS232 interface
- Fast serial IEC bus (like in the C128)
- Both IEEE488 and IEC bus are capable of being used as device for another computer (ATNA capability)
- An extra 8-bit I/O port in addition to the Userport
- Simpler and more versatile system bus (using the Ultra-BUS backplane:
- CS/A bus (my standard)
- Some Apple-II bus compatibility
- RC2014 bus connectors
- Built-in Userport extensions, like Joystick ports
Some pictures of the current state of the Ultra-PET
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Last modified: 2024-10-30