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Member Since 24 Mar 2011
OFFLINE Last Active Sep 18 2017 3:08 PM

#3839941 1088XEL Alternative Mother-Board Project

Posted by Van on Sat Sep 2, 2017 3:50 PM

I have tested TurboFreezer 2011 and it works fine. However, the cart and eci ports really need to be extended elsewhere to make it useful. The TF switches are underneath as you can see in the picture.attachicon.gif20170902_173411.jpg

Could maybe use RA connectors, ala XE. Not sure where to source the connectors, considering the straight connectors seem kind of rare.


#3839869 1088XEL Alternative Mother-Board Project

Posted by Van on Sat Sep 2, 2017 1:49 PM

Thanks Michael. I think I found a ball park comparison for loading speeds of different media


Standard SIO - 1.5K/sec

HS SIO - 5K/sec

PBI HDD - 50K/sec

So if these are close to reality, I should be fine loading from CF to Ext RAM banks :)


#3838166 Two disk drives on one power supply.

Posted by Van on Wed Aug 30, 2017 8:04 PM

Sure, but you would have to have a PSU that can supply the total amperage for both. It' far more do-able now a days with switching PSU designs that can supply 4-5 Amps and are smaller and lighter then the original PSU bricks. Back in the day you would have to use a very large transformer and Caps.


#3834905 MIDI Interface

Posted by Van on Sat Aug 26, 2017 10:06 AM

Yes, it's a SIO device. Dual Pokey should be no problem. It could actually be beneficial if one were to write a piece of software to use the Atari as a sound module. You lose channel 3+4 of the first for MIDI communication, but you could use channel 1+2 and the second pokey's channel 1+2 and 3+4 for three 16-bit audio channels in total.


Update: I'm going to order the PCBs tomorrow. I'll start with a batch of 10. More than enough components coming in the following weeks for 10 complete units.


@pack007, I checked the Fig-Forth code in your ATR and uses the external clock line, which this device does not support. I also glanced over the Midimaze ROM, and it does the same. But, I don't think it'll be too hard to "fix" them for this device. Perhaps somebody already did that "back in the day"?

I was also thinking this the other day about a dual Pokey set-up :)


#3833175 MIDI Interface

Posted by Van on Wed Aug 23, 2017 10:47 AM

Would be interested in bare board. A suggestion, add 3 pin header footprints under the DIN sockets to allow panel mounted sockets instead of board mounted DINs.


#3823587 YMari - OPL3 Cartridge by Tori / Yogi

Posted by Van on Tue Aug 8, 2017 2:49 PM


Yea I really didn't think you could keep Antic territory clear, but it would be nice to at least be able to cohabitate with the Sophia board. From an aesthetics viewpoint it would also be nice to not overhang the XEL board on the front side, but from what I see in many of the Mini-ITX cases perhaps that is not really an issue (looks like they always leave extra space in the front).


Looking good though, and nice to see another peripheral taking form that'll use the MPBI port on the XEL. Starting to really make a case for creating an MPBI adapter board for XL/XE systems as well (note to self: this will be the next project after the 1088XEL V1.1 release).


- Michael

Yes, not liking the overhang of the XEL, just looks sloppy. Clearing the GTIA/Sophia is very do-able. Clearing the other two will have to happen in the Z-axis, either with a cable or longer header pins and/or sockets like with the U1MB.


The M-PBI retrofit sound really good to me. Been thinking about placement. Pulling most of the signals from the CPU, would be tight with the KB when raising the CPU. Might consider the area over the DRAMs in a 800XL. May be interesting to incorporate a DRAM-to-SRAM mod on the board also. Just some 'blue sky' ideas


#3823489 YMari - OPL3 Cartridge by Tori / Yogi

Posted by Van on Tue Aug 8, 2017 12:51 PM

Yogi future considerations for a XEL V1.1 compatible version of your sound board, would be to shrink it down so that it doesn't extend beyond the Mini-ITX footprint, and to not overlap the GTIA for Sophia upgrades. Even better if it didn't overlap Antic because of VBXE, but that is likely not possible (you have a lot of stuff on your board).

Do you require a scaled PDF of component placement for next rev XEL?

- Michael

Agree :thumbsup: , was looking over your photos with Sophia installed, just yesterday. The overhang of the XEL 'front/bottom' edge is ~10mm, with the V1.0 board, will be adjusting the M-PBI footprints to allow for this.


The next iteration will shrink a bit, at least as much as possible. The header length sets the board width for the most part. On this proto I used a 2x22 footprint for one header, will be reverting to 2x17 headers. The use of the 'Adr Option' headers takes up board real estate also. If the address was locked in, could do away with some of these too. I'm reluctant to consider an SMD design just yet, but it would yield the smallest board. ATM this is a PoC, so getting it running and developing driver softs is the main push.


Direct mounting to the M-PBI, the board will at the least overhang the CPU and somewhat the Antic so would interfere with Antonia or VBXE  too. With these mods installed, almost the only option is a cable on the M-PBI header. This isn't a major issue for me, stock CPU and Video is fine here. I used an extra long 2x15 header for the M-PBI that adds ~10mm to typical pin length. This has the net effect of raising the attached PCB bottom 15mm above the top of mobo IC sockets but even this may not add enough clearance for the mods. Regardless of my setup, I don't want to close doors for others.


Using a ribbon cable extension allows more mounting options but eats more space in the case. For use in a XL or XE, would have to connect with cables anyway so remote mounting should be a design option anyway. Seems alot like 3D chess :)


#3822700 YMari - OPL3 Cartridge by Tori / Yogi

Posted by Van on Mon Aug 7, 2017 11:58 AM

Back from vacation last week. So here's an update.

Finished up soldering (will post pixs later) but still need to test the board, will set up a midiBOX Core8 with a test harness to run some tests. Also worked a bit on another board I got in, the cart port switcher, once I got it all setup will open a thread.


Decided to tackle an Atari DRO player as a HW demo, OPL files can be easily produced with DOSbox and should work with ScreamTarcker or AT][ or what have you. Wanted to get start in on the Atari code so went through LGB's C64 SFX DRO player. Added more Comments in the source and sorted out C64 and  OPL code. Then started editing the OPL related blocks, as the original is targeted to the OPL2 and the OPL3 has an expanded reg set. I'm posting a snippet of the main player loop, heavily commented, for anyone interested in the code:

.Attached File  Snippet of Atari DRO play loop.txt   5.51KB   41 downloads


It's only the start of the Atari port so don't get too excited :) I think the OPL code is correct but still have to replace all the Display and Keyboard code and adjust the timing delay routines. Thinking a simple GR.0 text display for starters. So lots of research still todo.


#3821275 1088XEL Alternative Mother-Board Project

Posted by Van on Sat Aug 5, 2017 2:03 PM

Well, being involved in some of the testing I can say that the design is solid. The issues we have overcome are/were minor (once discovered)  and a fair amount of 'human error'. All to be expected with a prototype :) Design errors and improvements have been incorporated into the release design so builders can avoid some of the pit-falls the beta boards had. Well worth the extra time spent!


I expect that whatever problems a builder faces will be due to a faulty part or faulty construction. This is not to say that building the XEL requires expert skills, it's just a matter of taking your time and double checking yourself. Any builder that can read schematics, identify parts, handle through-hole soldering and use a DMM should do well.


In fact it's remarkable that a new design, a complex design, could go from an idea, to a working prototype, to a refined release in under a year!  JOB WELL DONE :)


#3819272 1088XEL Alternative Mother-Board Project

Posted by Van on Wed Aug 2, 2017 4:35 PM

LOVE that case badge!!! Had to order a couple straight away :) Great find!!! They also do 'Atari800XL' and 'Atari600XL' badges that fit OEM cases, may have to get one or two of them too.


#3809491 YMari - OPL3 Cartridge by Tori / Yogi

Posted by Van on Wed Jul 19, 2017 2:27 PM

Look what came in the mail today! Too bad I won't have anytime to play with em for a week, but it's a good sign that the DACs come in the tape reel package, looks like true NOS :)



The OPL3s look legit also, so fingers crossed.


#3809337 YMari - OPL3 Cartridge by Tori / Yogi

Posted by Van on Wed Jul 19, 2017 10:44 AM

Wow very impressive! This project is moving along at a very good clip. I also like the simple way you implemented the MPBI pass-thru. On the XEL V1.1 board the MPBI has been pushed more towards the right, so that should help you out a bit as well with your space issues.

Question (unrelated to your project): did you go back to PH0 buffering and either a 74LS08 or a 74F08? I ask this because as you know Stephen's been having issues doing this on his XEL with the black Candle U1MB.

Looking good Yogi.

- Michael

Thanks, have a few more parts to order. :)


I still have the PH0 buffer by-passed. I can revert and try LS and ACT logic, have em OH. But today is kind of busy, getting ready for the trip.


#3809197 YMari - OPL3 Cartridge by Tori / Yogi

Posted by Van on Wed Jul 19, 2017 7:39 AM

UPDATE: Got the OSH Park proto boards in :) Still waiting on the Yamaha chips, shipped on Jun 23  :?  Anyway, started populating one with the parts I have on hand.


A test fitting on the XEL. The YAMari2XEL board overhangs the Beta XEL edge by 1/2", I'll re-position the M-PBI header placement to better match the V1.1 mobo.


A side note: in this pix you can see another mod board just above the YAMari, it's a $D2 page decoder. Breaks out the '138 Y2 to a second '138 that decodes $D2 down to 32Byte /CS blocks. The PoKEYs are still visible at $D200 to $D21F but other devices can be positioned in this I/O page such as a Covox at $D280.


Test fit.JPG


The headers: on the bottom-side is the 2x15 socket for the Beta M-PBI (design is changed to 2x17 header). This socket has long pins so they form the top-side header, Arduino style. There is also a 2x2 RA header to pick up the added 4 signals from the mobo. The blue jumper wires route the additional M-PBI signals to pins on the 2x20 header.


Bottom 2.JPG


Top-side: a 2x17 M-PBI header, conforming to the XEL V1.1 design and a 2x20 (30p M-PBI + 10 extra pins, for my own needs). There is an additional 2x5 header to connect additional XEL signals to the 2x20's extra pins.


Top 2.JPG


I still have to order a few parts but I'll be off line for a week, family event/road trip :) Hopefully the OPL chips will be waiting for me when I return.


#3807687 Atari 8-bit programming books: Man, I miss(ed) the eighties.

Posted by Van on Mon Jul 17, 2017 10:20 AM

Thanks for that. Most of them were scanned by me. It's nice to hear when someone gets some enjoyment from them. Many of them are easy to find today but some of them are really rare. I'm still looking for about fifteen books to scan.



Thank you for your work on these books :) Many found memories of going thru the Compute! series back in the day, typing in the apps and playing with the code. The scans are a fantastic resource to me as I get back to my roots.


#3807647 Bad news about myselve (Stormtrooper /Richard Vermeulen)

Posted by Van on Mon Jul 17, 2017 9:39 AM

Hope the tests find the cause and treatment. I can only guess what you are going thru, keep positive. There is nothing more frighting then facing the decline of our own body. Have Faith and Hope to overcome this, we're all routing for you.