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mytek

XEP80-II a new beginning

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Hello guys

 

"crimp on" and "ribbon cable" on the outside looks like crap to me.  I had to use it with my BlackBox and Floppyboard, but I neither like the looks nor do I trust it to be as foolproof as a joystick (extension) cable.

 

I don't like devices with cables fixed to it.  For all kinds of reasons.  There has to be a way to connect a cable to the PCB anyway.  If Michael would place the holes in such a pattern that those who prefer a female DB9 connector over a cable could just solder in a DB9 connector, those who prefer the cable could still use the cable (and leave the DB9 connector off the PCB).

 

Sincerely

 

Mathy

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27 minutes ago, mytek said:

Yes I've been kicking that around, and I agree that would be the easiest solution, thus allow one to buy an off the shelf cable instead of having to build a custom one.

 

Mathy is referring to the communications cable that goes between the Joystick DB9 and the XEP. In the original XEP80 that was terminated to a 4-pin header similar to what I have shown on my board iteration.

 

BTW, you were absolutely correct about it being better to go through the Luma input on the S-Video connector instead of feeding through the composite connector on my converter. Before if I looked real close I could see a bit of squirmy-ness on some text, switching to the Luma only input on the S-Video completely fixed that. So just to be sure I put it up on my 55" HDTV and it looks absolutely flawless.

 

DSC01778.thumb.JPG.65c521a01e9558edf01e7e0cab9a400a.JPG

 

Thanks for the tip 👍

 

Now it would be nice to get an adapter that breaks out the S-Video to two RCA plugs, preferable very short in length (I was using a cut S-Video cable for my test).

 

Absolutely no problem my friend! Thank you for the credit. :D

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Connecting the AV2HDMI converter to my board really requires a new approach in order to keep the costs down. And because I really only need one connection (LUMA), it just seems more reasonable to purchase a JST 1.25 mm 8-pin connector (with wires) to make that connection between the AV2HDMI and the CVBS output. this way I don't have to add in the cost of an S-Video adapter to pick out that one needed video signal.

 

The white plastic connector on the right is a JST 1.25 mm type, which is where all the AV pigtails normally connect to.

 

BTW, notice this board does have a part number: WS-Z51 which comes under the Wiistar brand. This particular one is either version 31 or 3.1 (not exactly sure), which appears to have been produced in late 2019. This particular one was purchased around the middle to end of last year off of eBay. I have another that should be just like it coming from Amazon, and will be curious to see what's actually inside.

AV2HDMI_module.png.dff8ce09f9098e419596ef470cacecd9.png

Quote

If they had used a male S-Video plug on the AV2HDMI pigtail, I would have just gone with a standard 4-pin Mini-DIN female PCB mountable jack on my board. However they opted to go with an inline female Mini_DIN jack on their pigtail instead, which would require a male PCB mounted jack on my board, and that doesn't seem to exist.

 

Both Amazon and eBay have a few sellers that handle what I'm looking for, and being from China you'll not get just one, but more like 10 or 50 pieces, and they often times come with the mating plug as well which I don't need. However they are dirt cheap coming in around $11 for 50 pieces ($0.22 each).

 

1791132127_50SetMicroJST1258PinConnectorPlugwithWire150mm28AWGeBay.png.405faee38445c03123c5a51efb1d0367.png

 

So at $0.22 it'll hardly add any cost to the board, so it really becomes a non-issue at this point.

 

I just need to decide upon how best to plug the non-JST side Luma wire into the CVBS output. It would be nice to still retain an RCA jack on the main board just in case someone wishes to use their composite monitor, and I do recall some piece of gear I had that used nothing more than a pin with a wire soldered to it for something like this. In that particular case it was just used for separating 2 pieces of gear that had a shared common ground provided by the power connections and only needed to connect to the center pin hole of an RCA jack for the signal (very similar scenario to mine). I'll cross that bridge when I get to it.

 

Here's the breakout on the JST connector (from left to right).

 

Wiistar_WS-Z51_AV_pinout.thumb.png.0abd4f5a29ecc17eb54b16fb0c64ce7f.png

 

On a different subject, I've been trying to decide on the Final Name for this new version of the XEP80.

 

Because it won't have a printer port like the original XEP80 had, I seem to recall someone else proposing the name XE80 on another XEP80 topic if a reboot of the XEP80 was to happen sans printer port. This kinda assumes that the 'P' in XEP was meant to stand for 'printing' capability, which seems reasonable. So on that basis XE80 does seem appropriate, and keeps the name very simple.

 

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Since it drops the printer interface, it only has half the functionality.  Therefore, it would be the XEP40.  

 

Oh, wait....  😀

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Hello Michael

 

Why not just call it XEP80-II?  Everything else would just confuse people.  When I read the title of this thread I instantly knew that somebody was recreating/redesigning the XEP80.

 

Sincerely

 

Mathy

 

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Hello StickJock

 

3 minutes ago, StickJock said:

Since it drops the printer interface, it only has half the functionality.  Therefore, it would be the XEP40.  

 

Oh, wait....  😀

 

In that case, XEP80/2 would be a better name. ;-)

 

Sincerely

 

Mathy

 

Edited by Mathy
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1 minute ago, Mathy said:

Hello StickJock

 

 

In that case, XEP80/2 would be a better name. ;-)

 

Sincerely

 

Mathy

 

That's funny, because I was thinking the exact same thing!  Like the PS/2 or OS/2.

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Thank you everyone for your input. But I think Mathy said it best, and that is to stick to XEP80-II, which is what I started out with and would be best to keep in order to avoid confusion.

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37 minutes ago, mytek said:

Thank you everyone for your input. But I think Mathy said it best, and that is to stick to XEP80-II, which is what I started out with and would be best to keep in order to avoid confusion.

Or play with pronounciation and go with XEP82 🤪

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On 6/25/2021 at 1:47 PM, mytek said:

Yes this would be a great project as well, and could really go places if someone with the knowledge to do so were to get behind it. However I would please ask that a new topic be started specific to this alternative for further discussion, so that this one can be allowed to document the progress and suggestions associated with this NS405 based derivative of the XEP80. BTW, my goal is to keep this project as close as possible to 100% compatibility with the original from a software/driver viewpoint, so as not to alienate any existing XEP80 applications with baked in XEP drivers.

 

The XEP80-II is a great project! My XEP80 overheats - I run it without the case. I can't find a good affordable display to use with it because it clocks the output at the wrong rates for NTSC. I have one out of about 5 displays the mostly works with it. And you're right to keep compatibility. You are also right about people talking about emulators for a couple of years and not doing much. I started thinking about it when I acquired my hardware a couple years ago. Finally, I decided to do something about it. I started an XEP80 emulator on June 6th using the FujiNet hardware as the development platform. There's an XEP80 branch in the FujiNet github project if anyone is curious. I have a 9-bit UART receiver and the XEP80 state machine from atari800 running. This will be the last post I put here about it. Good luck on your project!

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1 hour ago, jeffpiep said:

The XEP80-II is a great project! My XEP80 overheats - I run it without the case. I can't find a good affordable display to use with it because it clocks the output at the wrong rates for NTSC. I have one out of about 5 displays the mostly works with it. And you're right to keep compatibility. You are also right about people talking about emulators for a couple of years and not doing much. I started thinking about it when I acquired my hardware a couple years ago. Finally, I decided to do something about it. I started an XEP80 emulator on June 6th using the FujiNet hardware as the development platform. There's an XEP80 branch in the FujiNet github project if anyone is curious. I have a 9-bit UART receiver and the XEP80 state machine from atari800 running. This will be the last post I put here about it. Good luck on your project!

Great stuff, when I get a chance I'll have to check out your project :)

 

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Project Update: New Direction

 

Ok so I started thinking (always a dangerous thing), that I should probably take the suggestion from MacRorie he made in a PM discussion we had towards the beginning of this project. And that was to take advantage of some of the other goodness the AV2HDMI converter has to offer. For instance stereo audio pass-thru to the HDMI, and a way to also feed the color composite signal from the Atari through as well, which as it turns out isn't half bad when converted to HDMI. At first it went against my keep it simple policy for this particular project, but it really makes a lot of sense in the grand scheme of things (this should be a happy day for @MacRorie).

 

And lastly, since this required bumping up the PCB footprint just a tad to fit some of the extras, I now had the room to go with through-hole components for all the discrete stuff, and decided to only keep the glue logic SOIC devices due to the substantial size reduction this still affords. So the board is now a little bit better for the DIY crowd.

 

XEP80-II_revised.thumb.png.5053f1caff0c7409970e69a8d1ea672b.png

 

So the idea is to use a standard Atari DIN-to-RCA A/V cable that'll connect directly to J2. And this also incorporates Mathy's suggestion for the use of a DB9 (female) connector for the joystick connection using a standard off-the-shelf DB9 extension cable (I found an inexpensive source of these for just under $2).

 

The S-Video Luma signal of the converter is now dedicated to the 80 column output (hardwired in), and really does a kick-ass job in this role. For interconnection between the AV2HDMI converter and my board I'll be using a pre-made double-ended JST 1.25mm 8-pin cable (simple plug 'n'play).

 

The AV2HDMI converter I've locked into is the Wiistar WS-Z51 pictured below. I got one today via Amazon (Amazon Buy Link).

 

DSC01782.thumb.JPG.e187bd80b3e7fb9218a570bbaefbd294.JPG

 

These can also be purchased through eBay and likely AliExpress as well, so check around for the best deal.

 

This is what they look like when purchased, before disassembly to remove the PCB.

2083034722_WiistarWS-Z51AV2HDMIconverter.thumb.png.aca9fa28f85ac3a90274e40bc4042b28.png

 

So a little bit more about the operation...

 

When first booting up the XEP80 driver, the switch (SW1) should be in the up position which will allow the Atari's 40 column color video and audio to route to the HDMI. Once you have successfully activated the XEP80, the Atari screen will go black, and that is your cue to flip the switch down, thus enabling the 80 column video to display on the HDMI. The Atari's audio will still pass through, and be heard over your HDTV's speakers.

 

Currently to get back to the 40 column screen does require a power cycle as well as flipping the switch back up. this is a quirk of the converter which I will be looking at fixing as part of the final design.

 

EDIT: I think I have a solution that will take advantage of some of the unused gates already in existence in the design. I'll be creating a 'T' flip-flop which in essence has a toggle action, to then control a dual channel analog switch applied to both the CVBS and Luma to alternately deactivate one circuit for the other. The toggle will be replaced with a push button tact switch, and will toggle the flip-flop each time it's pressed. Should work rather nicely.

 

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But your XE80 will still work with just plain composite or Luma (same as the original), won't it?  Some folks (like me) still have original CRT's and other devices that don't have HDMI.  (Or will we need to purchase a HDMI to AV/S-Video down-converter?)

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Really liking how this is shaping up.  I've purchased the HDMI board you linked to.

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This looks great, except (IMO) for the hdmi converter. I got one just like that one, thinking that the lag was just about people being too picky. Soon I realized that even typing was painful, as the sound also got delayed and inserting and backspacing (does that word exist?) were the most painful, even after going thru all the options and setup of my TV. Finally when I got a Retrothink clone I realized the hype about it.

I have to clarify that I am not 100% sure that it was the exact same HDMI converter. I also got it from Amazon and it looked exactly the same from outside, but I never checked if the PCB was "WS-Z51"

Sorry, that I came to this forum and did not bring any ideas... I just want to tell my experience. I am sure @mytektested his converter and made the call that was good enough given the constrains.

 

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25 minutes ago, manterola said:

This looks great, except (IMO) for the hdmi converter. I got one just like that one, thinking that the lag was just about people being too picky. Soon I realized that even typing was painful, as the sound also got delayed and inserting and backspacing (does that word exist?) were the most painful, even after going thru all the options and setup of my TV. Finally when I got a Retrothink clone I realized the hype about it.

I have to clarify that I am not 100% sure that it was the exact same HDMI converter. I also got it from Amazon and it looked exactly the same from outside, but I never checked if the PCB was "WS-Z51"

Sorry, that I came to this forum and did not bring any ideas... I just want to tell my experience. I am sure @mytektested his converter and made the call that was good enough given the constrains.

 

Bear in mind the primary use case for this project though - monchrome 80 column text to replicate the functionality of the original XEP80. Any pass-through conversion is just extra for those who want it. 

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4 hours ago, Larry said:

But your XE80 will still work with just plain composite or Luma (same as the original), won't it?  Some folks (like me) still have original CRT's and other devices that don't have HDMI.  (Or will we need to purchase a HDMI to AV/S-Video down-converter?)

Yeah I'll see if I can do a jumper to send that through the yellow video jack, using it as an output instead of an input. Just need to work out the details.

 

39 minutes ago, manterola said:

This looks great, except (IMO) for the hdmi converter. I got one just like that one, thinking that the lag was just about people being too picky. Soon I realized that even typing was painful, as the sound also got delayed and inserting and backspacing (does that word exist?) were the most painful, even after going thru all the options and setup of my TV. Finally when I got a Retrothink clone I realized the hype about it.

I have to clarify that I am not 100% sure that it was the exact same HDMI converter. I also got it from Amazon and it looked exactly the same from outside, but I never checked if the PCB was "WS-Z51"

Sorry, that I came to this forum and did not bring any ideas... I just want to tell my experience. I am sure @mytektested his converter and made the call that was good enough given the constrains.

Even though I will allow for the use of the audio pass-thru and composite video to be sent on through from the stock Atari 40 column output, there are no guarantees as to lag or quality of those signals. Although truthfully I haven't noticed any issues with audio lag being so terrible as to affect the sound of typing, which after all is the main goal of this project - high quality 80 column text. But thanks for your observation, I will check this out and see if it is an issue, but in my tests yesterday I didn't notice anything - maybe the lag in my brain compensates :)

 

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2 hours ago, Ripdubski said:

Make check payable to?

:D

TBA... eventually :)

 

The schedule to get this to MacRorie is rather loose at the moment, as in no deadline has been set. I have incorporated all the changes into the schematic at this point, checked for lag (there is none that I can see), and have incorporated a way to use the board in analog only mode without the necessity of the AV2HDMI converter for those that would rather use an older style monitor. I have also begun the trace routing, with the right half of the board completed, but the damn left side is definitely being a challenge because of both the density of the SMD and the fact you can only easily route one side, with the other requiring a bunch of vias.

 

At this point your guess is as good as mine for how much longer it'll be to achieve a 100% trace routing :?

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Update: Yet a New Plan

 

Well after careful consideration, and trying to implement some of the better suggestions here's where I'm at. First of all I decided as long as I'm going to allow the Atari 40 column video to utilize the AV2HDMI converter, I may as well allow it to also use the S-Video input as well. So I added a Mini-DIN-4 jack for the S-Video connection. So this ended up expanding the X direction of the board to 4.2 inches. Well I thought let's make it a square board once again so up with the Y direction as well. The new board footprint is now 4.2 inches square, still considerably smaller then the original Atari XEP80.

 

When I did this, suddenly everything opened up and I was able to go with all THT components. This really made more sense with the ultimate goal to have this as a DIY board down the road, which I generally like to do with many of my projects. And in that aspect I only use SMD if it is absolutely crucial to some aspect of the project.

 

So here's what the all THT board will look like (I've already started the trace routing).

 

XEP-80_NEW.thumb.png.eb3d1af7c4ef60a28c797c3ee239b73a.png

 

The board is still intended to grab power from the Joystick Port, so that USB power connector is to provide power to the AV2HDMI converter.

 

The momentary push button for video input selection is on what's considered the front of the unit, so all the connections are at the rear.

 

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