stamasd wrote:

keenerb wrote:

Meanwhile, my programmer has been sitting in a DHL Global Mail shipping faciilty in Compton, CA for five days.

I honestly wouldn't have thought it POSSIBLE to ship something cross-country this slowly.

I never, ever use DHL. For many reasons - this being one of them.

Yep. Ebay vendor was "Free Shipping!", it never occured to me that there was a delivery service this goddamn slow in the year 2016.

Thankfully it is marked as "Tendered to USPS" this morning at 5:30, so maybe I'll get it by tomorrow or Thursday.

I mean seriously, how bad do you have to be for someone to say "Thank god, the USPS is delivering it now!"?

keenerb wrote:

I placed the jumper to enable the on-board speaker (jumpers 1+ 2), powered it on, and immediately smelled smoke.

Turned everything off and re-checked. Apparantly I jumpered 3 + 4, not 1 + 2, so I shorted +5v to ground. I have no idea if this may have damaged anything.

I just wanted to quote this because I DID THE SAME DAMN THING when i first brought the board up.. no damage tho. speaker worked. wondered why I went from booting to not booting and yeah.. jumpered the wrong pins.

BloodyCactus wrote:

keenerb wrote:

I placed the jumper to enable the on-board speaker (jumpers 1+ 2), powered it on, and immediately smelled smoke.

Turned everything off and re-checked. Apparantly I jumpered 3 + 4, not 1 + 2, so I shorted +5v to ground. I have no idea if this may have damaged anything.

I just wanted to quote this because I DID THE SAME DAMN THING when i first brought the board up.. no damage tho. speaker worked. wondered why I went from booting to not booting and yeah.. jumpered the wrong pins.

I'll send Sergey an email and let him know apparantly this is a common thing.

I know for me it went "Huh that's funny buzzing noise. Oh look, smoke." Followed immediately by the most 🙁 face I've ever made.

yeah i had my bench psu on 0.4a to be safe for the 5vrail so was lucky shorting didnt dump much current in as the bench over volt/overcurrent/short protection kicked in.

The trace from the GND terminal on speaker to the capacitor directly alongside U31 is open, so definitely burnt that out. I could jumper that along the back if needed though, I think. The capacitor itself measures same with my shitty little meter as all the other similar capacitors of it's type, and no other traces that I measured seem to have any issues.

programmer is out for delivery today.

What backplane is everyone using? Have you built Sergey's or using a pre-made one?

This is what I plan on using:
http://www.ebay.com/itm/221626452419?_trksid= … K%3AMEBIDX%3AIT

Haven't got around to start building it yet, got entangled with too many other projects.

I had a few 4-slot ISA backplanes laying around. Will be enough for 8088 board, floppy adapter, IDE adapter, and video card. If I didn't kill the 8088 I'll pick up the parts for the backplane as well,

I have 4 or 5 isa backplanes here. A couple have screw terminals with no PSU connector, these dont appear to work unless you can supply the -5, -12 to the lugs.

I'm looking at 8 slots. cpu/xtcf/network/vga/sound/somethingspecial 😀

Well I flashed the ROM but have no boot, no beep. Must have killed it, or one of the components I ordered is bad...

Actually, since that trace from the speaker was burnt out perhaps I should jumper that across the back of the board and see what happens. According to the board diagram pdf, pin 4 connects to C31 and U31. The flip-flop at U31 tested OK with my programmer.

I tested out all the logic ICs, they were all fine. I jumped the burnt trace and replaced all the non-logic ICs I had spares of (cpu, keyboardcontroller, etc.) and it's alive!

One strange thing: After a little while the system starts broadcasting a beep for some reason. I have no idea what's up with that, it seems to work fine but anywhere from 1 second to 2 minutes after boot it's BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEP...

nice! congrats. Damn I gotta get working on the XT CF Lite card...

Damn the 8087 runs HOT. I pulled it out, I bet it's pulling more power than the entire rest of the system. Not worth it just to speed up Lotus 1-2-3...

Tested out a bunch of games and apps last night, doesn't seem much slower than my tandy 1000TL. DOSShell has some weird blinking thing going on though, probably related to my EGA card rather than an xi8088 problem.

were you on turbo? Id expect it to get hot if your on turbo since it runs in lock step with the cpu.

I dont remember them getting super hot at 4mhz... but its been a long time so maybe they did.

BloodyCactus wrote:

were you on turbo? Id expect it to get hot if your on turbo since it runs in lock step with the cpu.

I dont remember them getting super hot at 4mhz... but its been a long time so maybe they did.

I actually bought an 8087-1, which is supposed to be a 10mhz part and I'm only running it at 8mhz in turbo.

I ran a quick google, and apparantly this is normal. The 8087 has 3x the transistors of the 8088, and apparantly this is the reason it's ceramic rather than plastic casing...

On an unrelated note, ordered the parts for the miniATX backplane of Sergey's. Need to add a turbo button to an ATX case somehow though. Has anyone written a turbo toggle app for this board?

Also need to track down an appropriately retro beige ATX case, or modify one of the Tandys I have laying around...

hmm off top of my head without testing something like this, build with nasm and copy it to the xi8088

1; file turbon.asm
2;; turbo on
3[bits 16]
4[cpu 8086]
5org 0x100
6start:
7	 in al, 0x61
8	 or al, 0x4
9	 out 0x61, al
10	 mov ah, 0x4c
11	 int 0x21 

1; file turboff.asm
2;; turbo on
3[bits 16]
4[cpu 8086]
5org 0x100
6start:
7	 in al, 0x61
8	 and al, 0xFB
9	 out 0x61, al
10	 mov ah, 0x4c
11	 int 0x21

I'm digging through the BIOS source and it seems like there's maybe a keyboard combination to toggle turbo status?

atkbd.inc, line 316.

Or maybe the actual turbo button is handled here, I don't know enough to be able to tell.

If it's NOT handled here, I bet it would be easy enough to add a key combination to toggle it.

Also, it seems like port 61h bit 2 might have been fairly cmmonly used as the turbo toggle, so perhaps there's already a utility out there.

http://bochs.sourceforge.net/techspec/PORTS.LST

Sergey's xi8088 page actually says bit 2, port 61, which is what I wrote my code from.

a jumper does need to be on turbo pins 2-3 to enable software turbo.

Well there appears to be some problem or other with my xi8088 still.

I purchased three NEC v20 cpus; one was in the board when I shorted +5v to ground and does not function at all. Witht he second installed, my board boots but ultimately starts playing a 400hz tone and will lock up. The third CPU causes the beep and lockup almost immediately.

The CPUs were obviously used, so I'm hoping perhaps they are simply bad; I've ordered a "NOS" 8088 and v20 from ebay and they should arrive next week.

Anyone know of a way to test a v20?

My 'NOS' V20-16's were also not NOS. you could tell from the pins they were a pull.

Dropped a 33mhz oscillator into the board replacing my 24mhz and it boots up in turbo.. soooo thats nice. but damn, I so must order my parts to complete my XT-CF-Lite so I can start moving forward!