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32k expansion for the side port - released

32k sidecar memory

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#51 arcadeshopper OFFLINE  

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Posted Mon Aug 8, 2016 8:25 PM

I appreciate the enthusiasm, but the product doesn't exist yet. So I am not taking names or making any lists.

The first breadboard prototype worked.

Once i get back to the USA and recover, I hope to have time to build the proof of concept pcboard that is waiting on my desk. But as i have discussed in this thread there is another prototype breadboard design i want to get working or understand why it won't work before i do another proof of concept pcboard.

Then if that works out, I'll price and buy a reasonable quantity of parts. And start building them for sale.

If i am lucky, i have an ah-ha moment, before my next trip, and can get some steps in motion. But I would guess that we are looking at October. That is just a guess.

-M@

 

Just in time for PRGE :)   take your time and recover from travel :)

 

Greg



#52 --- Ω --- OFFLINE  

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Posted Mon Aug 8, 2016 8:35 PM

 

Just in time for PRGE :)   take your time and recover from travel :)

 

Greg

 

That means he'll have to come up with yet another project for Fest West 2017!  :lolblue:



#53 jedimatt42 OFFLINE  

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Posted Thu Aug 11, 2016 4:11 PM

So I got back from Argentina yesterday, slept for most of the day, and today managed to reconstruct the prototype breadboard without buffer chips, and get it to somewhat work. 

 

It is using about 15ma. and only sort of works when powered off the TI +5v sideport.  This circuit doesn't work at all when powered off external +5v supply with shared ground. 

 

The early buffered version worked fine off the external power supply.  

 

So my question to anyone who understands digital electronics: Does this make sense? Is that part of what the buffers are for? 

 

-M@



#54 ElectricLab OFFLINE  

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Posted Thu Aug 11, 2016 4:35 PM

So I got back from Argentina yesterday, slept for most of the day, and today managed to reconstruct the prototype breadboard without buffer chips, and get it to somewhat work. 

 

It is using about 15ma. and only sort of works when powered off the TI +5v sideport.  This circuit doesn't work at all when powered off external +5v supply with shared ground. 

 

The early buffered version worked fine off the external power supply.  

 

So my question to anyone who understands digital electronics: Does this make sense? Is that part of what the buffers are for? 

 

-M@

 

With the external supply I'd double-check that shared ground, and make sure the voltage is staying at 5v. 

 

I wonder if the addition of buffers is affecting (data not being held?) the ability to read data. If you want to borrow my Logic Analyzer, it could shed some light. At least you'd be able to record some traffic and look at the timing. It's a Gould logic analyzer k205 and it is about as loud as a stock PEB, but useful. I even have the manual and several pods and connectors. I've not used it much other than going through its own internal diagnostics. Anyway you're welcome to it if you want.



#55 --- Ω --- OFFLINE  

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Posted Thu Aug 11, 2016 4:36 PM

 

It is using about 15ma. and only sort of works when powered off the TI +5v sideport.  This circuit doesn't work at all when powered off external +5v supply with shared ground. 

 

 

Question for you Matt,

   Have you ever considered taking the power from the 12v output on the back of the TI that used to supply the RF modulator?  You could step it down if you needed.  



#56 Stuart OFFLINE  

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Posted Thu Aug 11, 2016 4:52 PM

jedimatt42, on 11 Aug 2016 - 11:11 PM, said:

So I got back from Argentina yesterday, slept for most of the day, and today managed to reconstruct the prototype breadboard without buffer chips, and get it to somewhat work. 

 

It is using about 15ma. and only sort of works when powered off the TI +5v sideport.  This circuit doesn't work at all when powered off external +5v supply with shared ground. 

 

The early buffered version worked fine off the external power supply.  

 

So my question to anyone who understands digital electronics: Does this make sense? Is that part of what the buffers are for? 

 

-M@

 

Have you taken the GND from a couple of side port pins and connected them together, to make sure you've got a really good GND for the circuit if one of the contacts is a bit dirty?

 

The LS245 buffer will 'tidy up' a noisy signal but with the small board and few components, things shouldn't be that bad.

 

Have you got a multimeter to check the voltage at the ICs?

 

When you say "it only sort of works", what's it doing?



#57 jedimatt42 OFFLINE  

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Posted Thu Aug 11, 2016 5:26 PM

 

Have you taken the GND from a couple of side port pins and connected them together, to make sure you've got a really good GND for the circuit if one of the contacts is a bit dirty?

 

The LS245 buffer will 'tidy up' a noisy signal but with the small board and few components, things shouldn't be that bad.

 

Have you got a multimeter to check the voltage at the ICs?

 

When you say "it only sort of works", what's it doing?

 

The "somewhat works" bit is that I can write and read to 2000 and A000 in easybug, but stuff from the XB2.7 suite cartridge doesn't load. Things generally crash. Now, things generally crash with my cartridge port anyway... so I need to clean it since I haven't used it in a few weeks.  So I haven't done do diligence...   I got through a level of road-hunter off the triple rasmus cartridge, but then it fell apart on the second level...    

 

And... I didn't have the grounds connected...  ( I did at one point... hmm... )  and... now it works with external power... and the speech attached upstream... ok... that's just crazy how many mistakes can be made with things you've done a million times...  

 

the LED doesn't work the way I want, and I decided that might be a red-hearing / wild goose chase / poor indicator, because with the circuit I copied from Thiery's site, the LED is off because there is an opposing +5v charge on each side... So I'll look at controlling that differently and be happier...  As it is now, it appears on dimly for addresses that it shouldn't be on at all for. 

 

So, progress...  And I swear I had the grounds connected this morning! :)   Thanks!

 

-M@



#58 jedimatt42 OFFLINE  

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Posted Sat Aug 13, 2016 12:47 PM

Ok... So I have been debugging a non-problem. That is my ah-ha moment.   :)

 

I went ahead then and populated one of my experiment pc-boards finally. Using the Corcomp Diagnostics on the XB2.7 Suite, it passes the 32k memory test. 

Anyone have a better memory test tool? 

 

Anyway, after that, I proceeded to try all of my cartridges that have games requiring 32k. Much of the XB2.7 suite itself, JETPAC, Tex Turbo, Mad Marvin, Road Hunter, TI Scramble, Titanium, Sabre Wulf, XB, and FR99, with some images I know are 32k loaders... Everything worked nicely. 

 

Now, this pc-board has the buffers in it.  

 

Attached File  Screenshot_081316_112757_AM.jpg   169KB   7 downloads

 

Attached File  Screenshot_081316_114644_AM.jpg   155.24KB   9 downloads

 

Attached File  Screenshot_081316_114102_AM.jpg   127.95KB   6 downloads

 

Later today, I plan to take the buffers out, and jump them instead, then move on to hopefully smaller pc-board design with a some additional resisters this design is missing, and some pass-thru headers -- If all goes well. 

 

Anyone have any bright ideas on how to extend the edge connector?  Right now, it you put this downstream of a speech synthesizer, you need to remove the door on the speech synthesizer, or the board won't connect very well.  I feel like a half centimeter extension would be appropriate, and improve casing options. 

 

 



#59 Ksarul OFFLINE  

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Posted Sat Aug 13, 2016 2:03 PM

You could switch the connector to the right-angle version. . .I have some of those. You could also switch the connector to one with longer pins (the wire-wrap version, as they are super thick and stable). The problem with the WW type is the cost. You end up paying about $10 each for the connectors, with a minimum order of 14 (based on my last experiences with Digi-Key).



#60 jedimatt42 OFFLINE  

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Posted Sat Aug 13, 2016 8:22 PM

You could switch the connector to the right-angle version. . .I have some of those. You could also switch the connector to one with longer pins (the wire-wrap version, as they are super thick and stable). The problem with the WW type is the cost. You end up paying about $10 each for the connectors, with a minimum order of 14 (based on my last experiences with Digi-Key).


Ouch. :-)

Thanks... I sure wish I was a big company with a big market that could afford having custom parts manufactured. Haha haha haha.

-M@

#61 Stuart OFFLINE  

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Posted Sun Aug 14, 2016 3:53 AM

If the new PCB is going to be smaller, could you have it horizontal, with the 'extension' for the speech synth to plug onto as part of the PCB? Your current connector that plugs into the console - would the PCB fit between the rows of pins on that and you solder the pins to pads on either side of the PCB?

 

(Not sure if Ksarul was suggesting something similar or not?)



#62 Asmusr OFFLINE  

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Posted Sun Aug 14, 2016 4:23 AM

What are the red and white wires in the picture for, does it require external power?



#63 jedimatt42 OFFLINE  

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Posted Sun Aug 14, 2016 8:12 AM

What are the red and white wires in the picture for, does it require external power?


Yes, those are power at this point. Remember this is a board I had printed just to test the schematic. The breadboard prototype was too flaky.

The only thing the TI is designed to power off the side is the speech synthesizer.

My current pcboard proof of concept is missing 3 resisters that should be there, and will lower current draw in the final board. I have also run this without the buffers, which lowers current draw even more.

So it should be possible to run off the side power. Another however... My speech synthesizer outputs nothing on the +5v pass thru. I was not intending to support TI equipment to the right of my board. The passthru I intended was a set of headers for add on daughter board. So if you want speech, you have to use external power for my board.

Now, if you are handy, you could take power off the TI internal supply. But if you are handy like that you might as well just build one of the internal 32k mods.

I may put a jumper to allow running from the sideport power. You could mod your speech synthesizers to pass power as well. ( I will try and measure that before I recommend it )

-M@

#64 Sinphaltimus OFFLINE  

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Posted Sun Aug 14, 2016 8:39 AM

This all sounds very exciting. All the best to you. As for your connector issue, what about a small riser board between the connector and the main pc board just to pass the connections? It might add more than what you want but couldn't too much be better than not enough in this instance?



#65 Ksarul OFFLINE  

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Posted Sun Aug 14, 2016 10:12 AM

I've done a lot of experimentation with side-port boards while I was developing the side port splitter. If the board is horizontal, you have four options when it comes to making a stable side port connection. You can take a right-angle connector and connect it to the board with it extended as far as possible over the side (this requires a bit of a board extension to ensure clearance). You can take that right angle connector, straighten the pins, and solder them onto the board horizontally (also requires board extension--but it is a lot more stable over time). You can get the wire-wrap version of the connector, form the pins, and solder it over the board saddle style (like the modified right angle connector with the straightened pins--this is VERY stable). Lastly, get the saddle-style connectors right from the start and solder them in place (these are VERY stable). The first two options are relatively cheap (under $1 per connector), as you can get the connectors in quantity from Taiwan (but the wires are thin, which will affect long-term stability if you insert/remove them a lot). The latter options are much more expensive (about $10 per connector), but they will pretty much last forever.



#66 OLD CS1 OFFLINE  

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Posted Sun Aug 14, 2016 4:46 PM

The only thing the TI is designed to power off the side is the speech synthesizer.

 

Original designs are meant to be built-upon, perverted, extended, adulterated, manipulated... :)



#67 jedimatt42 OFFLINE  

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Posted Sun Aug 14, 2016 11:27 PM

 

Original designs are meant to be built-upon, perverted, extended, adulterated, manipulated... :)

 

That is sort of what I was thinking, by not wanting to do the traditional edge card pass thru... 

 

-M@



#68 OLD CS1 OFFLINE  

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Posted Mon Aug 15, 2016 6:27 AM

 

That is sort of what I was thinking, by not wanting to do the traditional edge card pass thru... 

 

-M@

 

Well, pooh.  Out of curiosity, do you know off the top of your head what the current supply is to the expansion port, and how much does your 32k use?



#69 jedimatt42 OFFLINE  

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Posted Mon Aug 15, 2016 7:53 AM

Well, pooh.  Out of curiosity, do you know off the top of your head what the current supply is to the expansion port, and how much does your 32k use?


The expansion port will provide 50ma.
My board should use < 15ma. I measured that off the breadboard without buffer chips, and since then I've removed the 74LS125 in favor of a single pnp transistor.

So the target use case I am aiming at is the console/speech/cartridge user that just needs 32k to play mad marvin carts or spy hunter carts or EA5 conversions off the FR99 cart.

So, I do see the value in switching my plans to allow speech to be downstream of the 32k, so all runs off that 50ma.

It looks like i have to damage something to measure what the speech actually uses.

-M@

#70 Opry99er ONLINE  

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Posted Mon Aug 15, 2016 10:14 AM

Why not make your board expandable to incorporate speech? If someone has a synth, maybe the case could be removed and the components attached to your board in some way. :)

#71 RickyDean ONLINE  

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Posted Mon Aug 15, 2016 10:24 AM

Why not make your board expandable to incorporate speech? If someone has a synth, maybe the case could be removed and the components attached to your board in some way. :)

Like a zeno board, only outside.



#72 --- Ω --- OFFLINE  

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Posted Mon Aug 15, 2016 10:33 AM

There is another alternative to power, it's not as neat or tidy, but it would be functional.

 

Something like this could be made up....

611sgyst5PL._SY355_.jpg

 

One side would be power only, the other side would be normal audio & video or in the case of F18A users just audio.

 

Or a variation could replace the  one pictured above and the other side could have a power connector for the new device.

 

b2ap3_thumbnail_3.5-to-MIDI.jpeg

 

It's not as elegant as coming directly out of the side port, but it would be able to serve the widest audience. 



#73 sparkdrummer ONLINE  

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Posted Mon Aug 15, 2016 11:32 AM

FWIW
I powered one of my nanopebs off the 5 volt line coming off the speech synthesizer with no ill effects. There's a couple pictures of it somewhere on here.

#74 jedimatt42 OFFLINE  

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Posted Mon Aug 15, 2016 11:53 AM

I intend to have a external power jack on the board, and a jumper to allow taking power from the side port.

-M@

#75 Shift838 ONLINE  

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Posted Thu Aug 18, 2016 5:13 PM

i can see me buying a couple of these when they are out!







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