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TI-99/4A with a Pipistrello FPGA board


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#276 speccery OFFLINE  

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Posted Thu Jan 19, 2017 11:28 AM

I had the other day a good session over instant messaging with Klaus (kl99) in getting the board I sent him working. That was great  :)

As you might expect there were a few hiccups, mainly in getting memloader.exe running on a system that doesn't have Visual Studio 2015 installed (it's a simple task but still needed to get done) as well making a new initialisation script that does not require Cygwin to be installed. Klaus did a great job in his side. Getting things to run was somewhat messy since the information and documentation is scattered over multiple places (here, hack-a-day, e-mail, messenger, GitHub) - Klaus thanks for your efforts.

I was happy to see that he got his board working, so also in practice the TMS99105 board can be made to run elsewhere than in my "lab"!

 

Erik



#277 Tornadoboy OFFLINE  

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Posted Thu Feb 2, 2017 8:48 PM

I just stumbled upon this project and I'm anxiously waiting to see how it develops! I've been hoping someone would eventually come up with a completely backwards compatible update to the 4/a that has most if not all of the add-on hardware built in, as well as the potential for new stuff!


Edited by Tornadoboy, Thu Feb 2, 2017 8:49 PM.


#278 speccery OFFLINE  

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Posted Sun Feb 5, 2017 11:39 AM

I just stumbled upon this project and I'm anxiously waiting to see how it develops! I've been hoping someone would eventually come up with a completely backwards compatible update to the 4/a that has most if not all of the add-on hardware built in, as well as the potential for new stuff!

 

 

Nice to hear you found the project interesting!

Well this thing is pretty compatible with the 4A and has most hardware built in. I think there is plenty of potential with the design, it runs approximately 7x the speed of a regular 4A. This could also be configured to quite closely resemble TI-99/2 or TI-99/5.

Real life has kept me very busy, I haven't had time to work on this during the last weeks. I left off working on the disk support. It kinda works through the serial line with the PC acting as a disk drive. Separately to that I have a program that can read files from a FAT16 formatted SD card. What I would need is the time and energy to glue these things together. Well the first step would be to just bootstrap the board from the SD card, i.e. load the system and cartridge ROMs off the SD card.

 

Erik



#279 Tornadoboy OFFLINE  

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Posted Sun Feb 5, 2017 4:15 PM

 

 

Nice to hear you found the project interesting!

Well this thing is pretty compatible with the 4A and has most hardware built in. I think there is plenty of potential with the design, it runs approximately 7x the speed of a regular 4A. This could also be configured to quite closely resemble TI-99/2 or TI-99/5.

Real life has kept me very busy, I haven't had time to work on this during the last weeks. I left off working on the disk support. It kinda works through the serial line with the PC acting as a disk drive. Separately to that I have a program that can read files from a FAT16 formatted SD card. What I would need is the time and energy to glue these things together. Well the first step would be to just bootstrap the board from the SD card, i.e. load the system and cartridge ROMs off the SD card.

 

Erik

 

Keep up the good work!



#280 FDOS OFFLINE  

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Posted Tue Feb 7, 2017 11:49 AM

I second the idea of using SAMS paging for this project, as I have two 1 MB SAMS PEB cards, and I do this paging in both my X4th99 & TIB+ projects.

 

fdos



#281 speccery OFFLINE  

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Posted Sat Feb 18, 2017 2:24 AM

I thought I link here too: http://atariage.com/...slideshow-demo/

There is a picture of my setup at the current end of the thread.

 

I tried running the Monkey Island demo with my Pipistrello FPGA as the cartridge and that worked nicely. I haven't had time to work on TI related stuff for a while, so it was nice to run this - also this proved that the speech synthesiser (thanks kl99!) can sit in between without affecting the operation of the FPGA board.

 

In case you are wondering what the heck is the mess on top of the TI - it is a Sinclair QL motherboard I've been trying to get to run. I replaced all of the 4164 DRAM chips with higher density 4464 chips, but so far it refuses to work properly...



#282 speccery OFFLINE  

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Posted Sun Mar 5, 2017 3:08 PM

It seems my TI-99/4A is not working well... If anyone is willing to depart with a working console that would be great (NTSC/PAL - doesn't matter, F18A will go in). I only have my one console, it seems it is time to get another one. Hardware development (in this case FinalGROM99 debugging help) is not easy if the bare console does not work...

Incidentally I will be visiting California / Bay Area from March 7th for a business trip - a long journey for me, but might help in getting a console?

 

Erik



#283 Bmack36 ONLINE  

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Posted Sun Mar 5, 2017 3:10 PM

Hi Erik,

 

I have one that I am not using if you are interested in it.

 

Let me know.

 

Thanks,



#284 Opry99er OFFLINE  

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Posted Mon Mar 6, 2017 10:33 AM

Our of curiosity, have you emulated the 9902 functionality yet? And, forgive me for my relative ignorance on FPGA technology, but can all the 74LSxxx logic be coded into the FPGA, or do you still rely on IC latches?

#285 speccery OFFLINE  

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Posted Sat Mar 11, 2017 7:34 PM

Hi guys, I want to take this opportunity to thank the many offers I have received to get an TI-99/4A console (I got one from Matthew yesterday when we met in the Bay Area - it was really great to meet him in person). I continue to be amazed by the people in the community! 

So for me it is great to know there are people in the community with many spare consoles. I hope I don't need to ask for too many more by blowing up consoles as I work through hardware projects... I haven't had much spare time lately, but I really want to get started with the FPGA based PEB replacement development. I assume it will be a process to work through a few iterations, but I'm starting to have a good idea what I want to achieve with the first version.

 

Erik



#286 speccery OFFLINE  

speccery

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Posted Sat Mar 11, 2017 7:41 PM

Our of curiosity, have you emulated the 9902 functionality yet? And, forgive me for my relative ignorance on FPGA technology, but can all the 74LSxxx logic be coded into the FPGA, or do you still rely on IC latches?

 

Sorry for the slow reply. No I have not emulated 9902 functionality yet, but this can be done. Especially now that I have access to ready made HDL for the 9902...

 

Regarding your second question, basically all 74LSxxx logic can be implemented in an FPGA very easily. FPGA based designs still end up having some modern 74 series components when connected to old computers, as the I/O pins of practical FPGA chips are normally not 5V tolerant, they only go up to 3.3V. So you need voltage level converters to both protect the FPGA pins from 5V signals, and to drive 5V logic. There are many different level converters available, most are 74 series components. 

In other words, all logic gates can be done in the FPGA, but some external buffers may be needed to protect the pins and provide sufficient drive strength towards 5V systems like the TI-99/4A.



#287 Opry99er OFFLINE  

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Posted Fri Mar 17, 2017 12:14 PM

Very cool. Thanks for the explanation. :)

#288 speccery OFFLINE  

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Posted Sun Mar 19, 2017 9:38 AM

Today I had some time to work on the console that Matthew gave me. I installed F18A and modified the shielding and the case slightly so the VGA connector is securely mounted. Not a big achievement - but it seems I have a stable TI-99/4A now. So stable in fact, that in the last 20 minutes or so I have not been seen any FinalGROM99 crashes... I am sure they will occur eventually, as there is no definitive fix in place with the board I've got. If it does crash, I'll see what happens with a regulator swap.



#289 speccery OFFLINE  

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Posted Fri Mar 31, 2017 12:20 PM

Wrote an update on the vertical bars discussion... let's see if I can put the link here appropriately.

 

http://atariage.com/...demo/?p=3731094

 

So now the thing supports 5th sprite detection.

TMS99105 + FPGA system emulating TI-99/4A running vertical bars demo by Asmusr





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