1088XEL Atari ITX Motherboard DIY Builders Thread

[+mytek]

... is a keyboard mandatory to be able to boot (as it was for older PC) ?

 

No it is not required to have a keyboard to successfully boot. However without one there isn't much you can do to direct the action.

 

It's really too bad that you don't have either another system that you can temporarily transplant your U1MB into, or another U1MB to substitute for the one in your 1088XEL. But it is very easy to break a trace on the U1MB when first learning how to change out the headers (I did it on my first attempt). All I can think of for the time being is to grab a magnifier and a bright light source and then scrutinize all the connections.

 

Good luck .

[+DrVenkman]

It seems so "easy" when you did it on this video.

 

Jon's videos do make it look so easy, don't they? However, as I learned way back in Post 176 or so, 53 weeks ago (already!), it's not easy the first time you try it! Or at least, it wasn't for me.

 

Good luck with figuring out the issues and overcoming them. Building these is a challenge but it's so rewarding when it works out in the end!

[+mytek]

The good news going forward is that Lotharek now manufactures the U1MB with straight headers, so no more modding required.

Posted on his U1MB page...

[Evidious]

Finally got these together and buttoned up, Thanks for everyones help with assembly and setting it up!!!!

[ebiguy]

Hi,

 

Everything is working now except the keyboard.

I am using a native PS/2 keyboard (no USB converter).

The NumLok is always on and none of the keys are working.

Every 4 seconds (approx.), the 2 other leds flash.

both POKEYs seems good and of course the PIC for the keyboard has been programmed using the JOY2PIC-Stick (bought from McRorie).

 

Any ideas about this issue ?

 

[Brentarian]

Hi,

 

Everything is working now except the keyboard.

I am using a native PS/2 keyboard (no USB converter).

The NumLok is always on and none of the keys are working.

Every 4 seconds (approx.), the 2 other leds flash.

both POKEYs seems good and of course the PIC for the keyboard has been programmed using the JOY2PIC-Stick (bought from McRorie).

 

Any ideas about this issue ?

 

I would try re-flashing the PIC and try again.

[+MacRorie]

I would try re-flashing the PIC and try again.

 

 

Also, I have encountered PIC chips that flash completely fine, but are bad or marginal chips. I would try a different chip as well.

[+mytek]

Hi,

 

Everything is working now except the keyboard.

I am using a native PS/2 keyboard (no USB converter).

The NumLok is always on and none of the keys are working.

Every 4 seconds (approx.), the 2 other leds flash.

both POKEYs seems good and of course the PIC for the keyboard has been programmed using the JOY2PIC-Stick (bought from McRorie).

 

Any ideas about this issue ?

 

 

The every 2 second flash of all the LEDs is telling me that the PIC's keyboard code is running, and you are seeing the watchdog timer time-out due to it likely not seeing keyboard scanning on the Pokey chip (U6). This could be attributable to the PIC having some damaged I/O pins, or not being properly seated in it's socket, or missing a connection to the Pokey. Also a bad Pokey chip could cause this as well. And there is always the possibility of corrupted code in the PIC, so re-flashing it as Brent suggested might cure the problem if that is the cause.

 

These PIC chips are so cheap, that I really wish people would buy more then the absolute minimum for the project. That way flashing another one is a good way to troubleshoot potential PIC issues.

 

Good luck .

[ebiguy]

I have 2 PIC and I re-programmed both.

The keyboard does not work.

I also tried to change the POKEY at U6 without success.

 

About the communication between TK-II and POKEY, What could I test (or check) more precisely ?

I have only a multimeter (no oscilloscope).

 

EDIT: Oups, forgot to say thank you to all of you who try to help me. I appreciated your quick answers !

Edited January 29, 2019 by ebiguy

[+mytek]

Ok so I think we can rule out the PIC as the crux of the problem (as well as the Pokey chip). So that only leaves the interconnections between the PIC and the Pokey, and perhaps the connections from the PIC to the PS/2 connector. Of course this assumes that the keyboard is good --- have you tested that on your PC or tried another keyboard?

 

Aside from testing the keyboard, I would suggest using your multimeter and do a continuity check of all that I mentioned above (schematics are available at my website --- see link in signature below).

[ebiguy]

Ok so I think we can rule out the PIC as the crux of the problem (as well as the Pokey chip). So that only leaves the interconnections between the PIC and the Pokey, and perhaps the connections from the PIC to the PS/2 connector. Of course this assumes that the keyboard is good --- have you tested that on your PC or tried another keyboard?

 

Aside from testing the keyboard, I would suggest using your multimeter and do a continuity check of all that I mentioned above (schematics are available at my website --- see link in signature below).

 

Hi Mytek,

 

You were right about the communication.

I checked again the solder side of the PCB and I found the problem.

If you look at pin 21 of U6, this pin is "lost" among many via holes.

And It was not soldered !!!

Now the keyboard works.

 

Many thanx for your help !

 

Sometimes, when the SDX prompt is displayed and I start typing something, the first character is doubled.

As if the keyboard bounces. And it is only with the first character. Did you notice that ?

[+mytek]

 

Hi Mytek,

 

You were right about the communication.

I checked again the solder side of the PCB and I found the problem.

If you look at pin 21 of U6, this pin is "lost" among many via holes.

And It was not soldered !!!

Now the keyboard works.

 

Many thanx for your help !

 

Sometimes, when the SDX prompt is displayed and I start typing something, the first character is doubled.

As if the keyboard bounces. And it is only with the first character. Did you notice that ?

 

Glad to hear you discovered the missing connection . Congrats on the troubleshooting. 9 times out of 10 this is what causes problems on a new build.

 

On the first key press being repeated. What computer is this being used on? Opps forgot what thread I was in . Of course you have a 1088XEL . Do a ALT+X and if it says XEGS=OFF, then do a CTRL+ALT+X to toggle it ON. Most likely that will cure what you are seeing. If that works then you are done, because that setting gets saved in EEPROM never requiring you to toggle it again. Hope that works for you.

[ebiguy]

Hi,

Now I would like to plug a VBXE in my 1088 XEL.
I found no post about 1088 XEL + VBXE so I am asking confirmation about the wiring needed to make it work.
I would do this :

VBXE 1088XEL

J3 P1 MPBI /IRQ
J3 P2 MPBI /EXT
J3 P3 MPBI GND
J3 P4 MPBI /CI

J1 P8 MPBI VB

But I have 2 questions
1) For J1 P8, is it better to wire it to MPBI VB or to MPBI /D6xx
2) What to do with J6 which deals with crystal ?

[+MacRorie]

Hi,

 

Now I would like to plug a VBXE in my 1088 XEL.

I found no post about 1088 XEL + VBXE so I am asking confirmation about the wiring needed to make it work.

I would do this :

 

VBXE 1088XEL

 

J3 P1 MPBI /IRQ

J3 P2 MPBI /EXT

J3 P3 MPBI GND

J3 P4 MPBI /CI

 

J1 P8 MPBI VB

 

But I have 2 questions

1) For J1 P8, is it better to wire it to MPBI VB or to MPBI /D6xx

2) What to do with J6 which deals with crystal ?

 

 

 

 

1) VB

2) J6 is connected to Pin 2 (two) at J20 (shorting jumper is no longer required)

[ebiguy]

 

 

 

1) VB

2) J6 is connected to Pin 2 (two) at J20 (shorting jumper is no longer required)

 

Thank you for your answer.

Just to be sure:

1) by J6, you mean J6 Pin 1 ?

2) should I also connect J6 Pin 4 to GND ?

[flashjazzcat]

I dug a couple of photos out of the beta testers' PM thread which may be helpful:

 

 

[+MacRorie]

 

Thank you for your answer.

Just to be sure:

1) by J6, you mean J6 Pin 1 ?

2) should I also connect J6 Pin 4 to GND ?

 

 

1. Yes.

2. Not necessary.

[ebiguy]

Hi,

 

VBXE works well with my 1088 XEL.

I have a some questions about video

1) There is a modification at the back of the 1088 XEL with a 0.01 uF and 2.2 kOhm (and a revised one with a jumper). I am using a DIN to Scart cable bought at coolnovelties with a LCD TV. Can someone clarify if and when this mod is useful ?

2) I am new with VBXE. I see a setting in 1088 XEL firmware asking for the VBXE base address (D6xx or D7xx). What is the recommended settings to avoid any conflict with something else.

3) What is the purpose of enabling the 2nd POKEY IRQ ?

[+MacRorie]

Hi,

 

VBXE works well with my 1088 XEL.

I have a some questions about video

1) There is a modification at the back of the 1088 XEL with a 0.01 uF and 2.2 kOhm (and a revised one with a jumper). I am using a DIN to Scart cable bought at coolnovelties with a LCD TV. Can someone clarify if and when this mod is useful ?

 

This modification is to isolate CSYNC from one of the pins (I forget off the top of my head right now). Its primary function was to allow any model of the SC1224 to be used with the XEL. Without the modification, only the JVC model works reliably. If your connection works and yo do not forsee changing it, then I, personally, would not do the mod. I do the mod on all customer machines just so they have the option.

2) I am new with VBXE. I see a setting in 1088 XEL firmware asking for the VBXE base address (D6xx or D7xx). What is the recommended settings to avoid any conflict with something else.

 

D6xx is the default address that most software will look at for the VBXE. My 800XL has it set to D7xx, because of a conflict, but it has been so many years now I have forgotten why,

3) What is the purpose of enabling the 2nd POKEY IRQ ?

I am presuming software conflicts/ease of finding, but I do not have a specific example for you.

[_The Doctor__]

it's a good idea to do the mod, incidentally there were jaguar to sc12244 cords that also only worked on one model or the other, there was another that worked with all of them and looked the same... nothing hurt only gained... modded is the way to go.

[+mytek]

Just to add to what MacRorie stated for modding the DIN-13 Sync lines...

 

A stock 1088XEL board comes with CSYNC tied to both the VSYNC and HSYNC lines on the DIN-13 connector. This was required in order to get the JVC ST monitor to work. However it doesn't work for the Goldstar version, and can also cause problems for other RGB monitors as well. What was really needed, was to have actual VSYNC going to the VSYNC output. Since that signal doesn't exist on the 1088XEL (or any other Atari 8-bit for that matter), it had to be faked by using an RC network deriving it's input from CSYNC, and basically attenuating the HSYNC component from this signal. It's not as good as having a real sync separator doing the job, but in most cases it'll work. On the upcoming 1088XLD this has been done the right way, employing an LM1881 sync separator IC.

[+DrVenkman]

So this isn’t really a “builders” question so much as it is a question about how the 1088XEL PBI BIOS and Hard Disk options play into things, so maybe a PM to Jon would be in order, though others might benefit from my ignorance (and Jon’s knowledge) ...

 

A guy on the FB A8 forum discovered/unpacked his Atari stuff for the first time in 20+ years yesterday. He mentioned that his crack of The Eidolon crashes right after the Lucasarts logo when he tried on his 800. I remember having the same issue as a teenager circa 1984/85 when I got a pre-release leaked crack as well. I tried the ATX file with my SDrive-Max on my U1MB-equipped 1200XL and sure enough, it worked with an XL OS but not with my padded-out copy of OS B (I didn’t try it on a genuine 800 and 10K rom).

 

Tonight I tried all four cracked versions of the title that I have on my CF card with my 1088XEL and all 4 of them crash, even with an XL OS. So next I tried DJayBee’s clean modern crack from his occasionally-updated thread here at AA and it still doesn’t load correctly from my CF card using the SIDEloader. So tonight I mounted that same modern crack as D2: in the loader, booted Disk Wizard II and made a sector copy of DJayBee’s crack to a physical floppy, disabled the BIOS completely and it booted right off; presumably it would also have booted from RespeQt on the SIO2PC device, though I dindn’t try it.

 

So I guess this long-winded question is: what does the Hard Disk option in the PBI BIOS do in the system “guts” that would prevent certain titles from working when loaded from an ATR on the FAT partition of the IDE device, when that same ATR works through SIO?

 

In (relative) layman’s terms for those of us who last seriously dabbled in 6502 Assembly Language 33 years ago if possible, lol!

[+mytek]

I don't know if this is the case, but similar things have occurred with other games, and I believe it had something to do with their use of specific zero page RAM locations that was in conflict with the BIOS. Jon will of course hop in here and set us all straight .

[flashjazzcat]

Before I do, copies of or links to anything which fails to work are appreciated in case it's possible to provide a fix.

Edited February 3, 2019 by flashjazzcat

[+DrVenkman]

Before I do, copies of or links to anything which fails to work are appreciated in case it's possible to provide a fix.

 

Sure, of course.

 

These are the two I was fooling around with last night. Neither of these will load for me from an ATR mounted via the Loader but when I wrote out version 1.1 to a physical floppy and tried via SIO, it loaded up just fine.

 

These files both came from DjayBee's excellent cracks thread; all of these were made from Farb's "clean" ATX images. The ATX files do load and run from my SDrive-Max so they are good.

Eidolon, The (1985)(Epyx)(US)!req 64Kcr CSS.atr

Eidolon, The v1.1 (1985)(Epyx)(US)req 64Kcr CSS.atr