https://bit-hack.net/2025/11/10/fpga-based-ibm-pc-xt/
Recently I undertook a hobby project to recreate an IBM XT Personal Computer from the 1980s using a mix of authentic parts and modern technology. I had a clear goal in mind: I wanted to be able to play the EGA version of Monkey Island 1 on it, with no features missing. This means I need mouse support, hard drive with write access for saving the game, and Adlib audio, my preferred version of the game's musical score.
The catalyst for this project was the discovery that there are low-power versions of the NEC V20 CPU available (UPD70108H), which is compatible with the Intel 8088 used in the XT. Being a low-power version significantly simplifies its connection to an FPGA, which typically operate with 3.3-volt IO voltages. Coupled with a low-power 1MB SRAM chip (CY62158EV30) to provide the XT with its 640KB of memory, and I started to have the bones of a complete system worked out.
Source code, schematics and gerber files: https://github.com/bit-hack/iceXt
(Score: 0) by Anonymous Coward on Wednesday November 19, @05:53PM (8 children)
Seems like some of these still work, just say'n...
https://www.ebay.com/b/Ibm-Xt-Computer-In-Vintage-Computers-Mainframes/162075/bn_7022347361 [ebay.com]
Stored somewhere, I have a NEC "laptop" that emulates an IBM-XT, two 1.2 mB 3.5" floppies (no hard drive) and I'm pretty sure it uses the V20 CPU. Did a lot of useful work back in the late 1980s, easily paid for itself.
It was heavy, but most of that was the large Ni-Cd battery (long dead). With a Li-Ion battery swapped in it might be fun to get going again...
(Score: 2) by turgid on Wednesday November 19, @07:07PM (1 child)
Is the V20 the one with the Z80 mode?
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 2) by RS3 on Thursday November 20, @03:39AM
I'm not expert, but I believe it can sort of. It has an 8080 emulation mode, so since Z80 can execute most 8080 code, it seems like V20 can execute much Z80 code.
(Score: 4, Informative) by epitaxial on Wednesday November 19, @07:11PM (5 children)
Keeping vintage machines running takes a good bit of engineering. Parts are aging and along with the typical bad electrolytic caps you'll find shorted tantalum caps. 7400 logic chips that have randomly failed. Hard drives with bad bearings, crashed heads, or electrical faults. That and prices are only going to increase.
(Score: 1, Informative) by Anonymous Coward on Wednesday November 19, @08:20PM
Old hard drives can be troublesome indeed. For my own activities I am not really interested in vintage storage systems, so I generally default to using modern storage. Of course other hobbyists have different priorities.
You can get MFM emulators to replace the 5ΒΌ hard drives common in old PCs; for SCSI-based systems like older macs and most unix workstations there is ZuluSCSI (the lastest version is claimed to reach close to FAST-40 speeds), and for IDE-based systems you can use any SATA drive with a cheap adapter.
(Score: 2) by JoeMerchant on Wednesday November 19, @08:35PM
Belt drives. I retired many a floppy disc system due to not caring enough to repair the aged belt drives.
🌻🌻🌻🌻 [google.com]
(Score: 3, Informative) by Mojibake Tengu on Wednesday November 19, @08:36PM (1 child)
It is easy to replace ATA disk with CF card. Just IDE with a different connector. Reductors were obtainable, could be done as custom board too.
Rust programming language offends both my Intelligence and my Spirit.
(Score: 1, Informative) by Anonymous Coward on Wednesday November 19, @09:11PM
For IDE systems just use any SATA drive and one of these adapters: Startech IDE2SAT2 [startech.com]. I think this is by far the most straightforward and cost-effective option, as CompactFlash cards are a much more niche product nowadays.
If you do go the CompactFlash route, note that for some unfathomable reason a lot of adapters fail to properly connect the two DMA signals on the IDE connector to the card. These will work fine with controllers which do not implement DMA, but anything modern-ish will successfully negotiate a DMA mode with the card and then subsequently fail all operations (on Linux there are driver options to force using PIO mode which will at least work, albeit slowly, probably other operating systems have similar knobs).
(Score: 3, Funny) by DrXenos on Thursday November 20, @01:54PM
This is why I gave all my vintage computers away. I don't have the skills to keep them in repair. The guy who came to pick them up was very happy but man was his wife pissed!