Most of these projects are 8-bit stuff for the Commodore VIC-20, Arcade games from the 80's or my own reincarnation of a 8-bit machine based on the 65C816.
All done with a specific idea or test in mind. Beeing testing GreenPAK, New circuits for USB Type-C PD Sink or FPGA implementation of USB 3.0.
FATVIC
My FATVIC is a replacement for the VIC chip with VGA output. It also has full memory on BLK0 and some other enhancements.
The thing I wanted to solve here was no drilling in the case, any changes reversible, and no wires hanging out through the casing, but VGA with audio. I solved this by desoldering the DIN connector replacing it with a plastic dummy that holds a small rigid-FPC up side down having a 8 pin miniDIN with VGA and audio. Fitting nicely in the large hole of the normal video DIN. The FPC connected to the FATVIC. If you want.
Otherwise it emulates the ordinary video through the ordinary DIN. Well is supposed to.
To have BLK0 full you also need to socket one of the decoder logic chips. Namely the 74LS138 for BLK0. This is also reversible though. The small board that sits in the socket detect if the FATVIC is missing and reverts to ordinary function. When enabled it also pulls the RAM1/2/3 on the cartridge port high to disable any 3k in a cartridge from being selected.
GCart Family
I have had a numerous variants on the GCart. It started in 2011, and I do not remember where I got the GCART naming from.
There has been two main families. The GCart, GCart BX and GCart MX. These have all memory often banked and in the range of MByte, WiFi, and often an IEC bus. SD Card and/or embedded massive FLASH.
The GCart Jr, is focused on low cost, but usually have quite a descent feature set.
Lastly we have GCart DCNT (Dirt Cheap No Thrills). This is typically only memory with no banking what so ever.
GCart Jr III
This is the latest of the Jr type.
- RAM at the lower 3k, BLK1, BLK2 and BLK3, as well as BLK5.
- It also have 16MByte of FLASH for applications that are cartridges or single loaded programs.
- Optionally it has an RTC, Display, SD Card, and a general MIDI synthesizer.
GCart DCNT
The Dirt Cheap No Thrills memory expansion. Sub 5 USD in BoM cost.
- Memory in BLK1, BLK2, BLK3, BLK5, The lower 3k as well as IO2 and IO3.
- Simple UI with 4 LEDs and one button, which also is a RESET button.
GCart MX
The Max memory expansion. The inverse of DCNT. Spare no expense style ...
- FPGA based. This is run on a 12k LUT FPGA from Lattice.
- Memory in BLK1, BLK2, BLK3, BLK5, The lower 3k as well as IO2 and IO3. All mapped into 16Mbyte HyperRAM with twin controllers.
- Builtin Meatloaf on a RISC-V soft MCU with a uBlox WiFi/Bluetooth. Both IEC attachment as well as a warp speed loader for 250kbps speeds.
- 16MByte internal FLASH and micro SD card for even more. Both connected to Meatloaf.
- MIDI IN/OUT.
- General MIDI synthesizer.
- UI is a segmented custom LCD display with the same illuminated reset/configuration switch as all the other.
With an optional internal encoder, instead of the ordinary UC5, other features can be unlocked. The internal encoder replaces UC5 and also encodes A14 and A15 on to the NC - Not Connected pin 20 in the cartridge port for a few other possibilities.
- HDMI output and emulation of the VIC chip, with many of the feature from FATVIC.
- USB Gamepad that handles both analog and digital controllers.
- Possibility for different Kernals and BASICS.
This is however the most ambiguous expansion I have done. Electronics is easy peacy, but all software will be quite a ride.