TinyBASIC 2.5g Released

Behold!  I present to you TinyBASIC 2.5g!

Thats right, it has been anticipated for some time.  I now feel comfortable releasing it into the wild.  So without further delay, the files are available below.  There are two version, one is a version designed to run on the G80-S Micro Computer.  The other is a version with will require you to write a few routines to work with your particular computer.  In the event that your memory is different than 32k ROM and 32k RAM, you’ll also need to play with the memory locations to get it to work properly.

If you have any questions about how to get it running, shoot me an email, I’ll be happy to see what I can do to help.

EDIT:  Thanks to Travis Hall for finding a pretty important typo.  The problem has been fixed.

tinybasic_2_5g

G80S_tinybasic_2_5g

Avaya ISAPC-00 ISA to PC Card Interface

While PC Cards (or PCMCIA Cards as they were mistakenly known) are a thing of the past, they can often be quite useful.  Take my Compaq SmartStation Laptop setup.  Being from the 486 era, and a laptop, there are not a lot of solutions for mass storage transfer.   There was no USB.  There are no commercially available adapters for installing a 5.25″ drive (although I made my own with my 3D printer).  The only solution you would normally have would be a Parallel Port Zip Drive.  But luckily for me, it does have two PC Card slots.  And since there now exists PC Card to CF Flash adapters, I have a solution for mass transfer.

But, in 1993, someone decided there was a need for a ISA to PC Card adapter.  In fact, there seems to be a few different controllers for them.  One of which is the controller in question here, the Vadem VG-469.  The other one, that I’m aware of, was made by Intel.  And is the basis for the Vadem product.

I believe this particular card, and others like it, were part of some industrial solution.  Someone needed interchangeability between a Laptop and a Desktop for their PC cards.  But the real reason I think this has to be an industrial design is due to the lack of drivers.  There seems to be enough information for a Windows 95 machine to use these controllers.  But not WFW 3.11, which would have been the default OS during the time this card was made.  Unless you were still primarily using DOS at the time (which there are also no drivers for).  That leads me to believe that it was likely for some other OS.  But that is speculation at best.  Maybe someone just needed a portable HDD, and this was the interface.  Thats right, PC Card HDD solutions did exist as well…

Whatever the case, it is an interesting piece of Tech History from the 1990s.  Check out the video below.  Enjoy.

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

G80S_v0_45t

3D Printing Warping Prone Parts

I’ve owned a Da Vinci Pro 1.0 for about a year now.  And I have noticed that like any other printer, the settings are crucial.  And I hope that this will help other owners.  And maybe owners of other machines as well.

3D Printing with ABS can be problematic from time to time.  ABS really shines when it comes to versatility.  Not only is it an easily accessible filament, but it is strong.  However, that strength doesn’t come without weakness.  And ABS has quite a few weaknesses.

First off, the sharpness of the print will not be as high as with other plastics. Due to the properties of the plastic, it just doesn’t lend itself well to printing high detail models.  But it excels at simpler ones.  This coupled with it’s strengths and it’s ability to be chemically bonded to itself with acetone make it a suitable plastic for creating enclosures.  And in electronics, we always need enclosures.

Secondly, ABS tends to warp.  And warping is exaggerated by larger parts with more mass. To break it down, if it is large, or flat, or has sharp corners, you will likely experience warping.  Or in the event that you do not experience warping, you may experience layer separation.

The root cause of the problem is that ABS tends to shrink as it cools.  So whether or not you’re able to make it stick to the build plate, you’re likely going to have some type of distortion.

This effect can be minimized to a degree, but will always be present.  A heated build surface is a must.  As is an enclosed build area.  These two items will help “keep the heat in”, and that will help the layers cool at a more uniform level.  But this isn’t a complete solution.  Even if you print slow, you may have problems with curling, or warping.

Below is an example of a warping prone part.  It’s large, it’s flat, and it would normally have sharp edges.  But I have designed this part to minimize warping.  Let me explain.

The first thing we need to address is mass.  Now this part was originally part of a larger piece.  That larger piece added a lot of height and mass to the model.  The problem with that is that with each layer you’re going to add a slight amount of additional “pull” to the piece.  Which over time, and increasing layers, can worsen the effect of shrinkage.

The next item we will look at is sharp corners.  There is no getting around it, sharp corners are like a magnet for warping.  Some people try to add “shields”, so to speak, around the corners to help maintain an even temperature.  However, I’ve had little luck with this approach.  What I have had luck with is “Mouse Ears.”  By adding a mouse ear to corners, I have found it does two things.  First, it turns a sharp corner into a round corner.  And secondly, it helps to tack the part down to the build surface, preventing it from peeling up.  An example of a Mouse Ear is here:

Another thing that we must discuss is build settings, specifically build speed.  The fact is, the faster you print the more warping you’ll likely get.  Warping happens as the piece cools. But the solution I have found is to allow the part a little time to cool down to the temperature of the heated bed before applying the next layer.  I do this by adjusting only my “Normal” Shell setting on the printer.  This slows the speed on the Outer Shells to 5mm/s.  This means that the shells take a much longer time to print.  Allowing the rest of the previous layer’s temperature to normalize.  See below:

How does this help?  Well, honestly I had experience ZERO warping on the part shown above with this setting.  However, it does substantially increase build time.  How much longer?  Well (and bear in mind the software’s estimates are never correct, they over state the time) with 20mm/s setting it is estimated to take about 3hrs.  With the 5mm/s setting it is estimated to take 5:40 hrs.  That is almost twice as long.  In reality, the part would likely take about 1:30-2 hours to print with the 20mm/s setting, and approximately 4hrs to print with the 5mm/s setting at 20% infill.  So there is a significant increase in time. But I have experience zero warping with this setting.

But there is one more disadvantage to using this setting that I’ve noticed.  At the place where the print nozzle starts (the Da Vinci has a tendency to start from the same spot for many layers in a row) there may be spots that are ‘missed’.  That is to say that they didn’t get filled in with plastic.  I believe this has to the do with the extrude ratio and the extraction.  I haven’t had a chance to experiment with those settings.  But I plan on testing in the future.

I hope this helps someone else with their print settings on the Da Vinci Pro 1.0 printer.

TinyBASIC 2.5g On The Horizon.

TinyBASIC 2.5g is very near release.  The source now includes routines for IN/OUT, PEEK/POKE, CLS, and DELAY.  And the code for executing Machine Code is being worked out.  So all things considered, it is just about ready to dump into the wild.

Along with the release of v2.5g, I will also be releasing the G80-S Monitor v0.50, which will include in ROM TinyBASIC 2.5g.  This greatly expands the ability of the computer by allowing the user to test new hardware on the fly without the need to write code in assembly, and modify the contents of memory from within BASIC.  I’m personally looking forward to the release.

As a note, the G80-S v1.0 boards are up for sale in the store, and on eBay here, and the Prototyping boards will be shortly.  And once I have a chance to do some tinkering with the hardware side of things I’ll be working on code for a FAT file system.

But until then, happy coding!

G80-S Prototyping Boards Arrive!

Retro Depot is happy to announce that the G80-S prototyping boards have arrived. They’ll be added to the store in a day or two.

So far everything looks good. Although we would suggest that you use extra tall stackable headers. Otherwise clearance may be an issue. But your particular setup may give varying results.

These boards feature breakouts for both the z80 bus as well as the PIO ports, a location for a 1117 Regulator (for 3.3v source), power indicator LED, Micro SD location with breakout (including spots for 1208 capacitors), and just over 1000 pads in a standard .100” grid.

G80-S v1.0 PCBs Have Arrived!

Great news fans!  The PCBs have arrived, been tested, and passed!  That means that I’ll will be able to get them up on the store for sale very soon!  I know many of you are anxiously awaiting the availability of these boards.  I’m waiting on a shipment of capacitors and resistors.  That should be coming in the mail before too long.  But it does take time, and because of this, if you order one of the early boards, you may be forced to purchase without the capacitors/resistors (something I plan on offering free of charge with these boards).

If that is the case, they are easy to find.  They are SMD 0805 footprint.  100nF for the capacitors (total of 16), and 10k for the resistors (total of 6).  One could make through hole work in a pinch.  But the safe bet would be to wait until the caps/resistors are ready.  You’ll know as soon as I do.  In the mean time, here is the front and back of the boards.  You’re excited, admit it.   😉

Also, International Shipping rates have been added to the store.  It’s a 3 tier flat rate.  It seems that for anything under about 8oz I can ship it for about $15 USD.  Once you cross over to 9oz it goes up to about $24 USD.   Above that, it’s best to ask for a quote.  But if we’re talking about a couple of PCBs, I should be able to ship 2-4 for $15 USD (plus the cost of the boards).  If you have any questions, just ask.

Contemplating Graphics

I’ve been thinking about graphics the last week or two. One of the items on my list of things to do is to build a video board for the G80-S. However, graphics pose a new problem…

Video Processors of the time period that this computer would exist were very primitive in respect to their capabilities. Wanting to have a machine similar in capabilities to an MSX, this requires me to use a chip compatible with the TMS9918A. The problem with this chip is that it doesn’t have the greatest of text modes. 40×25 characters just doesn’t work for the Monitor program, or any future aspirations of CP/M or DOS, which typically require 80×24 or 80×25 text modes.

There is a solution to this. Grant Searle’s adaptation of Daryl Rictor’s AVR video processor to 80-column text Mode is perfect for CP/M or DOS. But the problem is that: 1) It’s not compatible with the TMs9918A graphics, 2) the graphics mode leaves quite a bit to be desired.

That leaves me contemplating what should be done. I’ve got some ideas, but I figured in the mean time I would play around with a few different projects, at least until my new boards come…

One of the things that I’ve been wanting to play with was a 128*64 pixel graphics display. I bought one off of eBay a while back, and I’ve never toyed with it. 128*64 pixels isn’t a lot to work with. But I figured I should at least be able to get the G80-S to utilize it for it’s display…at least for TinyBASIC. I’d like to have 32-columns at the minimum. At 8-rows that should give a decent display. But cramming 32 characters in a 128 pixel wide display is a chore.

But with luck I came up with what I though would be a decent character set. I’ve attached the images below for your critique. The characters are 4×8 (width x height). That should allow for a 32×8 display and still permit normal graphics. Now I just have to write some code to test it.




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!

TinyBASIC: Variables, Memory, and Expansion

In my last blog post I shared that I have managed to integrate TinyBASIC into my monitor for the G80-S in a ‘mostly stable’ way. Now that has progressed from mostly stable to very stable. But further, the IN instruction has been revised to use variables. Which is quite handy, as it allows the programmer to not only write to I/O, but to also read from it, and make branches in his/her program as a result of those reads.

This is a big step, as it is the basis for other routines that can expand on the original TinyBASIC source code. Routines such as PEEK or POKE may need to use variables, and the ability to use variables to OUT to I/O is also important from a programmers viewpoint. And these routines just simply were not included in the original source, and I desire to have them available in my software. So as such, I’m further modifying TinyBASIC as I see fit.  And yes, when it is done I will release it into the wild.

Variables in TinyBASIC are straight forward once you understand them. To read from or write to a variable one simple needs to understand that they are nothing more than a predefined area of memory, and that they have a given structure.

This area of memory is defined as VARBGN in the TinyBASIC source. And in my personal example of code resides in 55 bytes of data starting from 0xFF00. Now, each variable is broken into two (2) bytes. However, they are not organized as you would assume, with the MSB being first, and the LSB being second (i.e. the way one would read the memory if layed out in from of him). No, TinyBASIC addresses variables just like the z80 addresses memory. I.e. if we refer to location FF88 in memory it will be listed as 88FF. Likewise, if we refer to a variable (for the sake of examples let say it is listed as 01h) in memory, it will be addressed like this:  01h 00h.  Strange, but ok.

Further, the first address of the variables is not ‘A’. I believe that it is ‘@‘ which I also believe is a pointer. But I have not confirmed this. One step at a time…

Now, this means that if we want to use variables it is as simple as figuring out which variable we want to use, and reading from or writing to that area of memory. Simple right!

As a result I have rewritten the IN instruction so that it now operates as a tool for loading a given variable for use by the program. It can be used in the following ways:

IN hh V
IN hh,V
IN hh=V
IN hhV

Where ‘hh’ is the port to write to in Hexadecimal, and V is the Variable ranging from ‘A’ to ‘Z’.

I’m still working on patching the OUT instruction to use variables. Sometimes the best way to solve a problem is to step back and let your eyes rest. And that is where I am at currently. I needed to step back until my eyes are fresh. But as of right now it can output a byte to a port.

The rest of the functions are still a work in progress. I have added a CLS function that can be used either direct or within code. I have also added a QUIT function which serves to exit TinyBASIC. So it is coming along.

Overall, my work on expanding TinyBASIC to be more usable, while maintaining a small foorprint, is progressing at a pleasing rate. And while this project centered around my G80-S computer, need is the mother of invention.  And as a result I will release the source once I decide that it is complete enough for release.

But for now, I leave you curious…