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Announcing a TI-99/2 on a FPGA. It uses an open source FPGA board, the Radiona ULX3S: The board has a GPDI connector that can be used to send video to an HDMI display and this is used by the TI-99/2 implementation. The USB2 connector is used to hook up a PS/2 keyboard. The TI-99/2 uses only a fraction of the board's capacity. It could easily hold a TI-99/4A, or a Geneve or TI-99/8. In fact, it can run a Minimig Amiga or a simple Linux. Unfortunately, the board is currently sold out, but a new production run is planned: https://www.crowdsupply.com/radiona/ulx3s The TI-99/2 code is written in Verilog and can be synthesised using the open source Yosys/NextPNR/Trellis tool chain. The full source code is here: https://gitlab.com/pnru/ti99/tree/master/ti99_2 Output is to the GDPI port and sends an HDMI compatible video stream in VGA resolution (the 256x192 pixel output area is doubled both horizontally and vertically, so each TI-99/2 pixel is 4 VGA pixels). Input is through a PS/2 keyboard (or a PS/2 capable USB keyboard) hooked up to the USB2 port. Cassette I/O and the HEXBUS interface are not implemented. The implementation is of the 32KB ROM version of TI-99/2. The system has been set up with 32KB RAM. All code is plain Verilog and should be easy to port to other FPGA boards. A standard (black&white) VGA signal is generated internally, so it should not be too difficult to run it on a board with a VGA connector. Many thanks to @mizapf and @speccery for their kind help in getting this done. Enjoy!
MAME TI 99-8 & TI 99-2 full usable download I have put together a workable MAME TI 99-2 & TI 99-8 packages. Just download and execute the batch file in the MAME directory. The 99-2 & the 99-8 never made it market for TI but they got fairly far along to the point of workable prototypes and even manuals (download manuals from http://ftp.whtech.com/datasheets%20and%20manuals/ ). The 99-2 works fine as is. It only has 4k of memory, no sound and B/W. Bo sure to use only the disk in the DISK directory. The sectors are different than the standard TI .DSK files. To access the disk use: OLD HEXBUS.101.SOMEFILE to save files use SAVE HEXBUS.101.SOMEFILE (somefile is your file name). there is a small file on the DISK BASIC-proj.DSK (the batch auto loads this disk) named HELLO. To load type OLD HEXBUS.101.HELLO In the batch file I kick off a text file that pops up next to the MAME screen with the 99-2 function keys and a vbs script that turns on the upper-case when the 99-2 starts and turns it of when the 99-2 ends. All this pertains to the 99-8. What is different about the 99-8 is the requirements from the PC. A i5 or i7 is required to work fast enough. I have set the 99-8 to work with my i3 in the batch file by skipping 1/2 the frames with -frameskip 30. If you have a i5 or i7 you can reduce this or eliminate it. Also, to keep the sound from stuttering I have set -audio_latency 34. If you have a faster machine, again, this can be changed of eliminated. I you have a PC slower than a i3, forget about it. Download the latest MAME at https://www.mamedev.org/release.html then add the data from the .ZIP files to the MAME directory. Here are the files: TI99-2.zip TI99-8.zip Have fun, HLO