[Ted Fried] wrote in with now not one however two (2!) new drop-in replacements for in style old-school CPUs: the Zilog Z80 and the Intel 8088. Either one of the “chips” run in cycle-accurate mode in addition to in an excellent turbo mode, which is able to run so rapid that you just’ll wish to use the Teensy’s inner RAM simply to maintain.
Either one of those designs have a {hardware} and device element. The PCBs mainly adapt the pinout of the Teensy to the objective CPU, with a number of 74VLC latches on board to do the voltage degree conversion. The remaining is an issue of emulating all the directions at the Teensy, which is extra than rapid sufficient to maintain. If this sounds acquainted to you, it’s mainly the similar means that [Ted] used final 12 months to carry us his alternative for the 6502 discovered within the Apple ][ and Commodore 64.
Why would you want an emulated CPU when the originals are still available? [Ted] inherited a busted Osborne I, an historical Z80 luggable. By way of changing the unique Z80 together with his emulation, he may just diagnose all of the device, which led him to find some unhealthy DRAM chips and get the outdated beast working once more. Or possibly you simply wish to play IBM XT video games at insane speeds?
And it seems like [Ted] has up to date his 6502 emulation to incorporate the undocumented C64 opcodes, so should you’re into that scene, you will have to be lined as neatly.
If any of this tickles your fancy, head over to [Ted]’s weblog, microcore labs, and apply alongside. Even though now that he’s lined lots of the well-known retrocomputers, we need to ask ourselves what processor goes to be subsequent?