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FPGA Based IBM-PC-XT

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Re: FPGA Based IBM-PC-XT

#13

Post by hintbits »

hintbits wrote: post #12
inglor_cz wrote: post #2

Wow. A lot of memories unlocked instantly. My first PC in 1995 was a very old IBM PC XT.

Same. I had a used Amstrad PC 1640, which had V20 @ 8Mhz and EGA graphics. The author's desire really hit home here.

correction: it had v30, which was 8086 rather than 8088 clone (16bit bus)

Re: FPGA Based IBM-PC-XT

#14

Post by ForOldHack »

haxxorfreak wrote: post #6

I love the hard drive sound emulation! I find that modern restorations of vintage hardware using SD cards to emulate drives are missing an important part of the nostalgic experience when they just start up completely silently.

The floppy disk usually made this straight up honking noise . I had a V20, but at 10Mhz. Never had a problem, except for formatting floppies. The V20 has a few tricks up it's sleeve, with a few less clock cycles on some instructions, and a Z80 mode to run cpm.

But,the real trick was to put real IBM roms in a clone board and run Xenix. When the clone roms are back in it still booted. Helped a lot to have a 2:1 Rll controller. Xenix was just pollute and delute - system V with some BSD thrown in and a slightly altered portable C complier that was later admitted to be wrong endian.

Did this Board have a FPU socket? Made turbo pascal run much faster. ( The 8087 version we got from the physics lab...) Especially the Hilbert matrix. And FFTs.

Re: FPGA Based IBM-PC-XT

#16

Post by [deleted] »

ForOldHack wrote: post #14
haxxorfreak wrote: post #6

I love the hard drive sound emulation! I find that modern restorations of vintage hardware using SD cards to emulate drives are missing an important part of the nostalgic experience when they just start up completely silently.

The floppy disk usually made this straight up honking noise . I had a V20, but at 10Mhz. Never had a problem, except for formatting floppies. The V20 has a few tricks up it's sleeve, with a few less clock cycles on some instructions, and a Z80 mode to run cpm. But,the real trick was to put real IBM roms in a clone board and run Xenix. When the clone roms are back in it still booted. Helped a lot to have a 2:1 Rll con…

[deleted]

Re: FPGA Based IBM-PC-XT

#18

Post by nsxwolf »

dlcarrier wrote: post #4

The title is a bit misleading; it's running on an 8088-compatible CPU, and a 1 megabyte SRAM, with the FPGA containing the display adapter and drive controller, as well as the glue logic.

This build demonstrate what’s actually interesting about FPGA to me. A pure implementation might as well be a software emulator. Being able to interface real chips makes this really neat.

Re: FPGA Based IBM-PC-XT

#19

Post by plantinthebok »

What was the most surprising timing constraint you had to meet for the V20 bus controller? The 8088's multiclock cycles were always under specified in original datasheets and I'm curious what reality looked like.

Re: FPGA Based IBM-PC-XT

#20

Post by asdefghyk »

A bit offtopic for this article , but I'm waiting for some FPGA's based "..device PC emulator?..." that can connect to my old hard drives from the mid 80s ... and boot them ....
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