Experimenting with home made computers usually results into the use of a pletora of discrete TTL IC in order, for example, to make the I/O address decode. For this reason I’ve started using GAL gate array logic IC’S.
This type of IC are programmable by a PC software and can substitute a complex logic network made of several TTL’s into a single package. For more info about GAL theory https://en.wikipedia.org/wiki/Generic_array_logic
One of the cheapest and easiest GAL to find to buy online is the Lattice GAL16V8.
This is IC works with only 5V supply, is TTL compatible and it’s speed usually is within 250Mhz!
It have 8 only input pins (2-9), one input/clock input pin (1), one input/~output enable pin (11) and 8 input/output pins (12-19).
To program this chip you need to write the description of the logic network that must be synthetized into it and compile the code. WinCUPL is a Windows software that have an editor, compiler and simulator.
This software is free to use and download from Microchip’s website. At this link you can find the download page with the software and manual. For my personal archive I’ve added it wincupl. This zip contains the software, license and documentation.
The code inputed into the software must be compiled and the resulting .jed file burned into the IC with an universal burner like Willem USB programmer. The file could be also simulated with the included simulator.
Included into WinCUPL installation directory there are several examples. You can learn quick the CUPL language following the examples.
You could generate the CUPL code file with the old PROTEL 99SE software, drawing directly the schematic, then compiling it with WinCUPL software.