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jedimatt42

32k expansion for the side port - released

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1 hour ago, jedimatt42 said:

 

https://github.com/jedimatt42/ti994a-32kmemtest/releases/tag/v1.4

 

I've updated this testing tool to cover Foundation 128K - 512K, Myarc 128K - 512K, and SAMS boards.   It is still just an 8K ROM. 

 

[email protected]

 

Oops, Greg found a bug... cause I didn't retest SAMS after implementing Foundation, and they both use some of the same crubits to bank switch.  Testing a fix now...

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Hi Matt and everyone!

 

I just did a homemade version of this 32k ram expansion based on Matt's design. (I basically just removed the LED)

 

I tried it with and without external power and am having the same issue, which is that it works fine for the memory test but fails when loading a game from cassette. I tried some 32k games dumped from cartridge. I'm using the cass24k2 program.

 

I derived the external power from the video port using a simple 7805 regulator.

So far, I'm still usinf 74LS chips instead of the HCT version.

 

I can also connect the Speech synth on the right side and it works fine.

 

Games from cassette work fine using the PEB with the 32k inside.

 

Please refer to pictures to get an idea of what I did.

 

Any idea?

 

Happy holidays and Thank you!

 

Pitou!

20191224_110408.jpg

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20191224_110456.jpg

20191224_110746.jpg

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Hi Matt and everyone!
 
I just did a homemade version of this 32k ram expansion based on Matt's design. (I basically just removed the LED)
 
I tried it with and without external power and am having the same issue, which is that it works fine for the memory test but fails when loading a game from cassette. I tried some 32k games dumped from cartridge. I'm using the cass24k2 program.
 
I derived the external power from the video port using a simple 7805 regulator.
So far, I'm still usinf 74LS chips instead of the HCT version.
 
I can also connect the Speech synth on the right side and it works fine.
 
Games from cassette work fine using the PEB with the 32k inside.
 
Please refer to pictures to get an idea of what I did.
 
Any idea?
 
Happy holidays and Thank you!
 
Pitou!
20191224_110408.thumb.jpg.586f92f08905b9cc0b0c0aed074b653b.jpg
20191224_110418.thumb.jpg.32d75cff1514f61c5752ddf0aec684cf.jpg
20191224_110456.thumb.jpg.e800c24fda4bd0f47b140f68c44f9f85.jpg
20191224_110746.thumb.jpg.3f32a2ee02f39b26a2b39b5a39971c4f.jpg
Are you running Matt's memory test or another one?

Sent from my LM-G820 using Tapatalk

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Yes, Matt's memory test. You can see it if you look at the 2nd picture.

 

I get all sorts of bug/instability when trying to run a program loaded from cassette.

Sometimes it can run then fails a bit later. Sometimes it freezes, other time I get garbled characters when doing a LIST and errors when doing RUN obviously.

 

Thanks!

 

Pitou!

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Try re-seating your cartridge.  I've had similar screwyness when my XB cart wasn't seated properly with my CF7+. Also try cleaning the cartridge port if the problem persists, and make sure the old felt pad inside is removed.

 

Hope this helps.

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@Torrax,

 

I just looked at that and it seems ok.

 

I'm not sure it's a contact issue, since I just did 100 passes memory test and all is fine.

 

Thanks for your suggestions!

 

Pitou!

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21 hours ago, Pitou said:

Yes, Matt's memory test. You can see it if you look at the 2nd picture.

 

I get all sorts of bug/instability when trying to run a program loaded from cassette.

Sometimes it can run then fails a bit later. Sometimes it freezes, other time I get garbled characters when doing a LIST and errors when doing RUN obviously.

 

Thanks!

 

Pitou!

 

TI BASIC will often load a TI Extended Basic program, but since TI BASIC doesn't understand many of the extended byte code, it lists as garbled characters, and often only crashes somewhere in the run.  Are the programs you are loading from cassette meant for the version of basic that you are using to load them? 

 

[email protected]

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I understand what you mean and yes, I did all tests with the right TI standard/extended Basic cartridge.

 

I also tried both on some games just to make sure.

 

Just as a simple test, can someone try let's say "Jungle Hunt" from the "favorite ti programs" here...

 

 

Look for Post #3 for the cass24k2 games explanation.

In the meantime, I will also do some more test on my side.

 

Also, it works fine in the classic99 and v9t9 emulators.

 

I'm pretty sure the ram exp. is good, just a matter of finding what's going on. :)

 

Thanks for your support Matt!

 

Pitou!

 

 

Edited by Pitou

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Hello,

 

I did a lot of tests and it works 100% when using cartridge games (or Flashrom99 using rom file requiring 32k).

 

However with BASIC it's very unstable

 

I'm gonna build the buffered version based on this http://www.nouspikel.com/ti99/titechpages.htm

as mentioned in Matt's first post and try again.

 

I'm open to all suggestions and/or tests if someone has any.

 

Thank you.

 

Pitou!

Edited by Pitou

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36 minutes ago, Pitou said:

Hello,

 

I did a lot of tests and it works 100% when using cartridge games (or Flashrom99 using rom file requiring 32k).

 

However with BASIC it's very unstable

 

I'm gonna build the buffered version based on this http://www.nouspikel.com/ti99/titechpages.htm

as mentioned in Matt's first post and try again.

 

I'm open to all suggestions and/or tests if someone has any.

 

Thank you.

 

Pitou!

Try a couple of different RAM chips. Two that I find work OK are an Hitachi HM62256BLP-7 and a Cypress CY62256LL-70PXC. Have seen problems with Alliance RAM, which is what I think you're using.

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Yes I'm using Alliance RAM. Ok I will try other chips.

 

Thanks!

 

Pitou!

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Well, @Stuart, thanks very very much. The Alliance chip was the issue.

 

I replaced it with another bigger 128k x8 Alliance chip and all is fine now. I did a small socket adaptor to keep high address lines high.

 

I tried some other Alliance 32k x8 that I have and it's the same issue. Same batch maybe.

 

I will order some Cypress.

 

Thanks again!

 

Pitou!

 

20200103_185447.jpg

20200103_185456.jpg

Edited by Pitou
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