PLD Plague – Problem Solved!

The G80-S has been plagued by the simplicity of it’s design.  The use of a single PLD to do all of the onboard decoding has led to an unusual issue.  One where the Programmer of choice is apparently selective concerning which PLDs it decides to program.

Thats right, it appears that the MiniPro Programmer just doesn’t like GAL22V10 PLDs.  I do not know why.  All I know is that some variants work without any issue. Some will not program at all.  While others have intermittent programming problems.  The interesting part is that I have not experienced this with any variants of the GAL16V8.

The solution to this issue has been to build a new programmer.  Luckily for me, there was a gentleman in Japan who took this task upon himself almost 20 years ago and created the ELM programmer and accompanying software.  See that information here:  ELM Gal Programmer.

Some time back there was another gentleman with the N8VEM project that decided to take the ELM programmer’s schematic, and create a PCB.  And then some time later I found the project and ordered a batch of boards.  And as a result of that brief history, I can now program GAL22V10s of any variety (not Atmel parts) with only some small modifications to the WinCUPL JEDECs (The software appears to not like all of the documentation in the JEDEC files).

The software requires a DOS computer with a parallel port.  Here I am using my Halikan LA-5040, a portable 386 machine with 5mb of memory and a monochrome LCD (or VGA out).  Here you can see the dump of the contents of one of the G80-S Micro’s PLDs.  It works!

So what does this mean, you ask?  Well, it means that we can finally start stocking the G80-S PCBs with the PLDs again!  Stock will be adjusted tonight to account for the additional availability.  Also, at least temporarily, we will be offering some of the ELM Programmer PCBs on the store.  However, we will likely be offering a variant of our own design (simplification of parts) in the near future.  Those PCBs will be added to the store as soon as I get a chance to add them.

Community Group on Facebook

Thats right!  First it was a Facebook Page, now we have set up a community group!

The idea behind this Group, as well as the Page, is to initiate more dialog between fans of the Website, YouTube Channel, and owners of the G80-S Micro.  Really!  I like talking to others who have the same interests!  I’ve called members at their request and talked them through problems with their computers.  I’ve help others port software over to computers of their own design.  And I have helped with all types of requests via email.  I truly enjoy having so many great people to support and follow my experience in electronics and vintage computing.  If not for you, this site would not exist.

And because of that, I want to talk more about projects, interests, and electronics.  And I want to invite you all to talk with each other about your interests!  And that is the intent of the Facebook Page and Group.

Below is a link.  But if for some reason the link eventually dies, just look for the Page on Facebook, and the group is added to it’s menu.  I look forward to talking to you all!

RetroDepot Community

RetroDepot is on Facebook

RetroDepot has joined FB! While this will be more of a ‘this is what is currently happening’ type account, meant to share the day to day activities rather than the formal posts on the website, I thought it would be a good idea to build a community. One where others can comment, share their own projects, and participate with others of like minds. The link is below, enjoy!

Website Update, and Other News…

It’s been a while since I have been able to update the website.  That has mostly been due to the holidays, but also general problems of being an adult, like work…

But, fear not. I have managed to make a few updates this evening.  There is now a downloads section available by using the main menu at the top of the site.  Also, I’ve added tabs for Links, as well as condensed the Store into a tab where the cart and the checkout can be accessed.

I’ve worked on the downloads page to the point that I think it is functional.  It looks ugly to me, but it serves it’s purpose.  Maybe I need some nifty graphics or something…

I’ve got to finish working on the TinyBASIC source.  It has been brought to my attention that there is another issue with it, although it is not something that I have toyed with.  So I’m not sure where it went broken.  The average user will probably not notice it, but if you are trying to use programs found on the web, you may run into problems were it concerns the syntax.

I received a batch of boards for the N8VEM SBC V2, and some Harlequin 48k boards.  I may be offering some of those in the store before long.  I would like to build them first to make sure the boards came out as expected.

I am working on building a N8VEM SBC V2.  I am currently waiting on parts from Mouser.  Their website said that the parts would leave their warehouse 3:30hrs after I ordered 3 days ago, and I received an email this morning stating that they would likely be shipped today. And, they would send me an email when they had shipped.  It’s now 9:30pm and that email has not arrived.  Broken promises….  But I’ll get a blog post, maybe a video, of that up as soon as it’s complete.  I also have an 8-slot ECB backplane on the way from John Coffman.  It’s the 167mm version of that board, so I am really looking forward to getting this setup.  I plan on putting this system into a 19″ 5U rack mount enclosure.  Along with a front panel that displays address, data, and status lights.  I am thinking something along the lines of the Magic-1 as seen here:

I’m also, as we speak, printing up an enclosure for my N8VEM Zeta SBC V2, and the ParPortProp board.  Thats more of a work in progress.  But I may get a few pictures up as soon as it looks halfway decent.  I’m no artist, especially when it concerns 3D objects.  But I try.

So here is to making 2018 a great year!!!

2nd Batch of Counterfeit GAL22V10s??? Or not???

Well, I discovered a package in the post today.  This time an order of GAL22V10B.  Upon opening the package I took note of how good the condition of the ICs were in comparison to the previous batches I have ordered in the past.  These really do look to be in good shape.  However, there are obvious signs that they have been previously used.  Such as slight wear on the pins.

But will they program, that is the question.  Well, I am here to tell you that the answer is…..  Nope, I couldn’t get so lucky.  I have only tried 10 or the 50 that I ordered, but I will tell you this, with this many that are bad I can’t see many of the others working.

So this brings me to my next question.  Why am I having so many problems with these PLDs???  Is it my programmer?  It’s worked fine on 16v8s and other 22v10s for some time.  But I have run into the problem before.  See the picture below:

I have run into this several years ago, and actually posted about it over on AtariAge, here is that post.  It’s mentioned in post #11.  And it’s the same problem we see here.  So that begs the question, are these “Re-Caps” that have been labeled as ‘GAL’ when they may actually be ATF22V10s???  That would explain the problem programming (Atmel variants use a different algorithm to program the PLD, but the JEDECs are compatible from my understanding).  But that is just speculation.

If anyone can shed light on this, I’d love to hear from you.  I’ve got about a dozen dozen of these things that are refusing to program that I’d love to salvage considering that they cost about a $1-3 depending on where you buy them.  But for now I am just assuming they’ve been programmed too many times.  The funny part is that they verify as blank…I’m wondering if they were erased and the lockbit was set?  Although I’m not sure that would make a difference….

If you’re interested to know where I got them, here is the eBay link:

Now here is another interesting bit, there are several feedbacks for this item from this seller, stating that everything was as it should be.  And the listing says that they’re 100% tested and working.  So now I have to wonder, is it the chips, or is it my programmer???

The Quest for More

Prototyping has begun.  Working up a standard for using an SD Card is the end goal.  But not just that.  I actually have some other plans for a “project” to go along side the SD card.  Not something that will be added to the overall computer.  Rather something that will just be a fun project FOR the computer.

But to do this, I need more I/O.  A lot more.  Because of this I decided to add another 8255 PIO and a z80 PIO.  The latter for it’s Mode 3 operation which will come in very handy with the SD card.  Also, since we will be doing file handling routines, it might make sense to have a RTC so that we can determine the the current time.  I had several ICM7170s on hand, and with the addition of a watch crystal and a coin cell, I should be able to rig it to work.

Progress is still a little slow due to work, but updates will be posted regularly.   As progress is made, that is.

Also, changes have been made to the Product Pages for the G80-S computer to reflect some needed information.  And a download page for the software will be added shortly.  I ask that if any bugs are discovered that they be reported, and I will issue a patched version.

Do you have a project that you used the G80-S or the TinyBASIC 2.5g software for?  Shoot me an email.  I’d like to get a picture, and possibly do a write up about your project.  Better yet, shoot a video, and I’ll add it to the blog crediting you! (With your permission of course).

Got a Website centered around vintage technology, software, or other hardware projects?  Shoot me an email, with your website address.   I’ll add it to an upcoming “Links” page.

G80-S v0.45t Stable Available for Download

While I iron out some of the details for the release of v0.50b and the v2.5g of TinyBASIC, I figured I better post an updated download for the currect version.  This is a stable pre-release.  And as such, not a lot is going to change between v0.45t and v0.50b.  I’m mostly just working on cleaning up code at this point.  If you’d like to check out the change log, it is attached below.  If you’d like to download the software, I’ve included it too.

I would have like to have already released the v0.50b by now.  But as we all know, sometimes life just gets in the way.  If you have any questions shoot me an email.  The Contact Us page  is your friend.

Also, there is still some availability of the PCB with the PLD option. I’m looking for a dependable supplier for these older parts. Once I do, they will become a more permanent option.

CHANGELOG – v0.45t


G80-S v1.0 Boards In Production

That’s right boys and girls! The first production run of G80-S v1.0 board has been ordered, confirmed, and are currently in production.

Some of you may be wondering what changes were made between the Beta run and the v1.0 boards. Well, to answer that question, not many. Firstly, and the most important aspect, the IEI line has been fitted with a resistor to VCC. This will allow SIO/DART interrupts if desired. It doesn’t affect current G80-S software. The other changes were simply cosmetic changes to the silkscreen layer. Everything should look pretty now.

Once the boards arrive I’ll get them checked for issues, but the layout hasn’t changed. So the only issues, if any, should be cosmetic at this point. (I had put quite a bit of thought into the board when designing it).

Also, I have designed and ordered a first batch of prototyping boards for anyone who wants to tinker with other hardware. This board will have breakouts for both the z80 bus as well as the PIO pins.  And will have a place for a Micro-SD card and a 1117 3.3v regulator. These changes will simplify modification for CP/M or testing with other hardware by allowing the user a way to expand the board while keeping the same footprint.  With stackable headers you could add quite a few items to the computer.  Just food for thought.

Happy Computing!

Popular Request: Microphone Pop Filter

Well, after suggestions from several viewers on my YouTube channel concerning the issues with my microphone, I have decided to break down and buy an el-cheapo pop filter.  Nothing special, here is the one I decided to purchase:

Double Layer Studio Microphone Pop Filter

It’s nothing fancy, but hopefully it will work until I have a chance to do research and invest in an audio interface and better microphone.  We’ll see.  But the good news is that it should at least help!  So look forward to future “hopefully pop-free” videos.

And for the record, it has already been ordered.  Whether or not I can hold off until it arrives before shooting my next video, that is a question for another day.  Although I do have a video I am REALLY wanting to shoot before too long.  However I have to do a little more work to get ready for it.  Maybe I could stretch it out until this weekend?

G80-S Micro Schematic and Source

I’ve been meaning to upload the source and the schematic for the G80-S Micro for some time now.  I just haven’t gotten around to it.  However, I had some time to do so this evening.  So attached here is the schematic, and the source code.  It’s the v0.25b version of the software.  Use them well.

Also, a link to the Source has been placed on the product’s page in the store for the Beta boards.  So if you want to buy a board, you can download the software there.  If you don’t want to buy a board, but want to play with my design, the schematic is here and the source as well.  Have fun!