30 replies to this topic

[Ksarul]

I've had some time to work on the 512K ROM cartridge again, and got a new set of boards in that doesn't require inverted signals--which also allowed me to switch to a 74LS378 as a latch, so the whole 512K should now be easily bank switched in 8K increments without external switches.  I did this as an alternative to the GAL board using Matthew's expanded 74LS379 code, mainly for those who don't have access to a GAL programmer.  Both board versions are software compatible with each other, though the GAL version can be used in either inverted or non-inverted mode.

Tursi has been working on the GROM side code.  That code is a work-in-progress dependent upon his available time, so it may be much later in the year before we see it (he has been very busy lately, and I'm just really glad he likes this idea enough to keep it in his project list).  Note that earlier versions of the code on his site don't work with this board, due to some pin change requests on his part.

We've got most of the detailed board documentation done (Jon/Tursi/Jim), though it may still change a lot as testing progresses.

Here is a picture of the most recent prototype:

Attached Files

•  V6H_ROM-GROM.jpg   296.74K   48 downloads

[retroclouds]

Very nice! Looking forward to that.

[Willsy]

I'm looking forward to the sheer geek factor of being able to use GROM and GPL

[acadiel]

I'm going to need to get a PLCC socket for the prototype testing.  I don't think I have any spares left.   I do still have spare 49F040's though, I believe.

Great job, Ksarul!

(On a side note, I wonder if Tursi can get Multicart to page and bank 512K instead of 128K?) :-) :-)

Edited by acadiel, Thu Jan 26, 2012 8:36 PM.

[Ksarul]

I already figured you'd need some more of the sockets, Jon, so they are included in the test package.  It will be in the mail tomorrow. . .along with a few more of the 49F040s  

[Tursi]

acadiel, on Thu Jan 26, 2012 8:35 PM, said:

(On a side note, I wonder if Tursi can get Multicart to page and bank 512K instead of 128K?) :-) :-)

Was already accounted for! Just change the HIGHEST equate to the new highest bank switch address. For 512k that would be 607E, IIRC.

* Set this to the highest bank address to scan
HIGHEST EQU >6020  * 128k

Of course, there's no accomodation in the program for scrolling the display...

Edited by Tursi, Thu Jan 26, 2012 10:17 PM.

[acadiel]

Tursi, on Thu Jan 26, 2012 10:16 PM, said:

acadiel, on Thu Jan 26, 2012 8:35 PM, said:

(On a side note, I wonder if Tursi can get Multicart to page and bank 512K instead of 128K?) :-) :-)

Was already accounted for! Just change the HIGHEST equate to the new highest bank switch address. For 512k that would be 607E, IIRC.

* Set this to the highest bank address to scan
HIGHEST EQU >6020  * 128k

Yep, but I was wondering what happens when we get to the bottom of the screen... does it start overwriting stuff past the screen table in VDP RAM?  Or will it scroll or start a new screen?

[acadiel]

Ksarul, on Thu Jan 26, 2012 9:58 PM, said:

I already figured you'd need some more of the sockets, Jon, so they are included in the test package.  It will be in the mail tomorrow. . .along with a few more of the 49F040s  

You, my sir, rock!

Thanks!

[Tursi]

acadiel, on Thu Jan 26, 2012 10:18 PM, said:

Yep, but I was wondering what happens when we get to the bottom of the screen... does it start overwriting stuff past the screen table in VDP RAM?  Or will it scroll or start a new screen?

it just stops, if I remember right, and won't enumerate any further. There's no code in there at all for scrolling or new screens. I suppose we could add that at some point (or anyone else could, hehe. ).

[Willsy]

Tursi, on Thu Jan 26, 2012 11:39 PM, said:

I suppose we could add that at some point (or anyone else could, hehe. ).

I could take a look at it. Where do I download the source code?

[acadiel]

Source emailed to Mark

[Ksarul]

Yesterday was really warm here, so I decided to do a test that required warm weather.  I used my molds and cast a new cartridge case.  It came out pretty nice, as you can see from the photos below.  I can only do really low-volume casting right now (one pressure tank and one set of molds), but I may eventually get another tank so that I can use two sets of molds simultaneously.  Many thanks to Gregg Eshelman for helping me to get this set up in the first place.

Attached Files

•  Cartride_Case_1b.jpg   183.63K   48 downloads
•  Cartridge_Case_2b.jpg   160.73K   49 downloads

[Willsy]

WOW! Those look awesome! Are you able to do translucent ones?

What about different size ones to accomodate larger circuit boards?

[Tursi]

Hope I'm not stepping on your toes, Mark, but I updated the multicart menu code to support paging and scrolling. It probably can handle about 300 entries now, but I didn't test the upper end. Bob wrote to ask me about whether I was updating it, and after talking to him a bit I just decided to see how hard it was.

Attaching the code, binary image, and readme here. The basic changes are that the joystick will now scroll the list up and down, and for keyboard interface, if there is more than one page, it will display "PRESS 1-x" (where 'x' is the number of pages available), and pressing the key will change the list.

 Multicart.zip   13.34K   13 downloads

[atrax27407]

Tursi,
You are a gentleman and a scholar. I'm sure the community appreaciates all of your work on this and your other projects.

[Willsy]

Aha! Saves me a job! Cool! Thanks

[acadiel]

Wow... can't wait to put together the new toy and do some testing.  Hope to have some time this weekend to solder the new '378 one (and burn the 512K Multicart) and also try Tursi's new "bank switch test" program on both the '378 and GAL boards.

I'm really looking forward to this weekend!!

Ksarul and Tursi.. you guys rock!  

BTW, I was thinking about the 4K fixed/4K variable TI XB Banking scheme.  What if we still banked on 8K, but just kept the first 4K consistent at the beginning of each bank for XB?  Yeah, it's wasting 4K on the chip by duplicating the "fixed 4K", but I don't see any reason why it wouldn't work... thoughts?

[Willsy]

Where can I get a board(s)? Are they for sale yet?

[Tursi]

acadiel, on Tue Jan 31, 2012 9:13 PM, said:

BTW, I was thinking about the 4K fixed/4K variable TI XB Banking scheme. What if we still banked on 8K, but just kept the first 4K consistent at the beginning of each bank for XB? Yeah, it's wasting 4K on the chip by duplicating the "fixed 4K", but I don't see any reason why it wouldn't work... thoughts?

That's what the emulators tend to do. The images for XB are already built like that

[Ksarul]

Mark, it is possible to do clear, translucent, or other random colors (using material types I have not purchased yet), but for the moment, I can do basic black. . .as to the board availability--I made about 50 of them with this run.  If they work right, I'll have some I can part with as I've only used 10 or so as test articles, but for the moment they are only in the hands of a small test group.  You'll be one of the first to know when that changes. . .

Hey Jon, using the 4K idea, you could probably put pointers and a command loop in the fixed 4K of each bank and build a 256K BASIC Interpreter using the 4K variable banks. . .of course, a similar idea would make for one mondo game. . .

[acadiel]

Well, I had a chance to play around... the stupid eBay PLCC-DIP adapter is very flakey in my programmer; I had to buy a new one today, because I'm tired of messing with this $2 piece of crap that I have..

Here's the new one.. eBay Auction -- Item Number: 270894619549

Anyway, I finally got Tursi's Banktest program working, and attached is a picture of the cartridge board and a picture of the Bank Test.  I've burned a MultiCart with the new code posted in this thread and will try it as soon as my kids finish playing Story Machine.

The power up bank on the TI 74LS378's is pretty consistent; it's the very top 8K bank, just like it was on the 74LS379's.

Attached Files

•  image (2).jpeg   703.7K   28 downloads
•  image (3).jpeg   1.14MB   28 downloads

[Ksarul]

Excellent!  Many thanks for doing that piece of the testing, Jon (and to you Bob for egging us on)!    

Mark (Willsy), now that I know that the EPROM side works, I can probably send you one to experiment with.  You won't be able to use the GROM side until Tursi gets a chance to work his magic though.  Fire your current contact data at me--do you have the necessary assembly bits/tools handy, or should I send one pre-assembled like I did for Bob?

The real question now is how much interest is there in more of these?

[acadiel]

My only recommendation so far is to see if we can get a higher grade PLCC socket if we produce these.  I've had nothing but headaches with getting the F040 to sit correctly (all pins contacting) in the cart board.   It might be worth getting one of those sockets like I posted above (that don't have the DIP) that we could solder to one of these proto boards for testing.  That way, you can push down (I think) on the socket, and the F040 pops out.

Also, it might either be my crappy eBay adapter, or something I did, but I have three F040's that my programmer complains about 3-4 bad pins.  I've tried two adapters with the same result.  I'll try them again in the ZIF pop-out adapter I just bought on eBay when it comes in to see if they're salvageable.

Nice work on the board, Ksarul!  You really outdid yourself here.  This is one amazing piece of work.  The same with Tursi's GROM chip.

So, what's the pinout difference between the 1284 between the '379 version I had and the one you just produced?  Is it in line with the GAL board now?

Edited by acadiel, Sun Feb 5, 2012 4:18 PM.

[Ksarul]

Jon, if you look at the 378 board and the GAL board, everything on the GROM side is identical--this was to ensure full compatibility.  As to the differences between it and the 379 version we did in 2010, Tursi asked me to move four of the data lines to different positions on the Atmel to allow the Analog section to be added using the pins there.  He also asked me to make some minor changes on the address lines and the pins coming out to use when reprogramming the Atmel. Note that the GAL version should work fine with code for this board as well--just set the jumper for non-inverted outputs.

Did you ever get the GAL code operating on one of your boards?

We might be able to fit one of those sockets on a test board.  They look a little wider than the usual ones, so they might impact the capacitor between the socket and the outer edge of the board. . .

I'm glad you like our new toy. . .

[Willsy]

Ksarul, on Sun Feb 5, 2012 3:49 PM, said:

Mark (Willsy), now that I know that the EPROM side works, I can probably send you one to experiment with.  You won't be able to use the GROM side until Tursi gets a chance to work his magic though.  Fire your current contact data at me--do you have the necessary assembly bits/tools handy, or should I send one pre-assembled like I did for Bob?

That's great - I'll send you a PM. A pre-built board would be nice, but I do have soldering facilities etc.

Thanks

Mark