Xi 8088 by Segey Kiselev

Discussion about old PC hardware.

Xi 8088 by Segey Kiselev

Postby BloodyCactus » 2016-6-10 @ 14:42

Based on the marvin 'Anyone Built this PC-Retro' thread, it seems a few of us have or are building (or going to build) Sergey's Xi 8088 board. I thought it would be nice to collect everyone's experience in one thread.

I'd be curious to know what chips you eventually used, speed of oscillator etc.

Myself, I've collected all Intersil / Harris CMOS versions of the main chips with, I think one exception of the 82c88 from UM. I have a NEC V20-16mhz CPU, but will be clocked at probably 12/13.3^ on turbo but I may dial that back to 8mhz since I dont know if all the support chips can reach those speeds beyond 8mhz. maybe 10mhz..

So who has built one or is building one, what chips did you select? what oscillator speed etc? what did you end up using for video?
Last edited by BloodyCactus on 2016-6-30 @ 14:14, edited 1 time in total.
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Re: Xi 8088 by Segey Malinov

Postby stamasd » 2016-6-10 @ 15:10

My PCB is still in the mail. I ordered chips a few months ago, I think I'm still missing a few but I have to take an inventory and see what's missing. Like I said in the other thread I prefer to use 74F if I can find them, otherwise AHCT/ACT. A few I could only find in LS. I have a number of 8088s in different speeds, and a couple of V20s. Plan on not gong over 8MHz to begin with.

For me, the most troublesome chip to find was actually the keyboard controller. :)
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-10 @ 15:25

Here's the Mouser part list I found. Seems I've picked up some incompatible parts so don't assume this is correct! It's also only a partial list, there's many items I had to find on Ebay (and I already lost my 8087!)

I also found 16mhz V20 but only picked up a 24mhz oscillator; I'll worry about faster speeds than that later, the crystal will be easy enough to replace!

I've put together a floppy controller and an OPL2 adapter of Sergey's. I was going to assemble a VGA card but I picked up a cga/ega card, I think that's far more fitting to the device than VGA.
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Re: Xi 8088 by Segey Malinov

Postby BloodyCactus » 2016-6-10 @ 18:58

stamasd wrote:For me, the most troublesome chip to find was actually the keyboard controller. :)


you can get the recommended via chips for NOS like 99c. i have like 10 off them here.
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-10 @ 19:01

yeah I ended up with 10 of the keyboard controllers for $3...
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Re: Xi 8088 by Segey Malinov

Postby BloodyCactus » 2016-6-10 @ 19:13

Im thinking of going to 24mhz oscillator too, as that will run my V20 at 8mhz when on turbo.
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Re: Xi 8088 by Segey Malinov

Postby stamasd » 2016-6-10 @ 19:36

I do have 5 of the KBC now but they took forever to arrive from China because I couldn't find them at a reasonable price anywhere closer at the time.
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-14 @ 23:46

Good news, I didn't lose my 8087, it hadn't arrived yet.

I'm curious whether my 8087-1 (10mhz) will be OK running alongside a 12mhz v20?
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Re: Xi 8088 by Segey Malinov

Postby Anonymous Coward » 2016-6-14 @ 23:51

In my experience an 8087-1 will not run at 12MHz reliably, and because of the way it is connected to the 8088 it will make the entire system unstable even if you're not using it. I couldn't even squeeze 11MHz out of mine (I tried 2 of them). Supposedly in the mid 80s there was a company that specialized in FPUs that sold 8087-1s that were cherry picked which ran fine at 12MHz. I think the company name was "Microway".
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-14 @ 23:53

R.I.P. 8087 dreams then.
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Re: Xi 8088 by Segey Malinov

Postby BloodyCactus » 2016-6-15 @ 01:03

yeah, I didn't even bother to buy an 8087. it has to run in lock step with the cpu, and 8087s only come 4.77/5/8mhz. I never needed an fpu even when i had a 286, not much point trying to run povray or something on 8088...

some of my chips are rolling in. I'm always amazed to find these old chips NOS. people sitting on pallets of the things.

I got 74F chips for everything but the 3 not made in the F family. only 1 of the 74F chips was not carried by mouser which was interesting.
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-15 @ 01:28

I've got everything but the common IC chips arriving tomorrow. Gonna get all the resistors/sockets/etc. soldered and sort out my IC parts list and try to figure out if I've got everything I need...
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-15 @ 23:21

How important are the chip ID suffix identifiers?

The xi8088 lists Mouser 595-SN74ALS20ANE4, 595-SN74ALS20AN, 595-CD74ACT20EE4, 595-CD74ACT20E; I have no idea what the NE4,AN, EE4,E stand for, and whether they're all essentially the same part compatibility-wise...
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Re: Xi 8088 by Segey Malinov

Postby stamasd » 2016-6-15 @ 23:28

They usually refer to the type of package, and to delivery options from manufacturer to OEM (bulk, tape, box etc). As long as you got the package right, you can ignore that.

Also, I got my PCB in the mail today. Gonna have fun soldering all the small parts over the next few days. Then onto IC sockets, yay. :roll:
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
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Re: Xi 8088 by Segey Malinov

Postby BloodyCactus » 2016-6-16 @ 01:58

often they refer to stuff like temperature range / binning. sometimes its the dip or soic etc part type.

my nice blue pcb's showed up today from Todd :) sweet! tomorrow i might solder the sockets on..
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Re: Xi 8088 by Segey Malinov

Postby stamasd » 2016-6-16 @ 04:10

BloodyCactus wrote:my nice blue pcb's showed up today from Todd :) sweet! tomorrow i might solder the sockets on..


I recommend starting with soldering the smallest parts first, resistors/caps, then moving on to sockets. You may find it very difficult to solder a small resistor between 2 sockets that have already been placed. :)
I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O
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Re: Xi 8088 by Segey Malinov

Postby BloodyCactus » 2016-6-16 @ 12:15

since its all through hole, piece of cake. now if it were smd birdfeed, yes ;) birdfeed before sockets!
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-16 @ 13:11

BloodyCactus wrote:since its all through hole, piece of cake. now if it were smd birdfeed, yes ;) birdfeed before sockets!


It was a great relief that the project involved no SMD parts.

When I put my 1mb RAM board together from lo-tech I was most disheartened when I opened the box and this appeared:

Image

Managed to get it working though. After using up about an entire spool of desoldering braid, anyway...
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Re: Xi 8088 by Segey Malinov

Postby matze79 » 2016-6-16 @ 15:28

just use a fluxpen.. much easier..
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Re: Xi 8088 by Segey Malinov

Postby keenerb » 2016-6-17 @ 01:29

Allrighty. Started on my board this afternoon.

5:30pm: Workspace ready and iron heating up.
Image

Oh no,tragedy has struck. Mouser sent me a broken oscillator socket. :(
Image

ALmost finished. Missing a few headers,10k resistor array, and the oscillator socket.
Image

Populated with the ICs I have so far, four hours later:
Image
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