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RS232 port


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#1 Vinnie D. OFFLINE  

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Posted Tue Jun 19, 2018 3:30 PM

I've noticed one big critical flaw in the TI-99 and that's the lack of any form of serial cable. This means that aside from the cassette port, anything you want to attach absolutely must go through the sidecar. Now of course there's the PEB, and the RS232 sidecar unit. One is incredibly bulky and expensive, the other is hard to find and expensive. So I thought to myself, if the sidecar memory expansion can be brought down into a tiny little board that you barely notice, when the original was quite massive, why couldn't an RS232 serial interface be made to do the same? Has anyone done this yet? How difficult would it be to build such an interface for the TI-99/4A's sidecar expansion? Ideally I'd like to include a passthrough as well so that it doesn't terminate the chain (as my RAM expansion already does that). Any suggestions?

#2 FDOS OFFLINE  

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Posted Tue Jun 19, 2018 3:38 PM

As of this moment, the NanoPEB is the best single unit sidecar for the TI-99/4A.  It provides 32K memory, emulates 3 floppy disk drives, and has a TI type serial port.  If you have the "right" 32K expansion, you can go for the TIPI sidecar.



#3 Schmitzi OFFLINE  

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Posted Tue Jun 19, 2018 4:02 PM

here some more RS232-sidecars:

 

Attached File  TI-99-4A-HW-SIDEPORT-RS232-v1.00.JPG   291.61KB   8 downloads

 



#4 arcadeshopper OFFLINE  

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Posted Tue Jun 19, 2018 6:08 PM

Don't forget the UberGROM has a serial port as well usable with hdxs and timxt

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#5 Vorticon OFFLINE  

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Posted Wed Jun 20, 2018 6:07 AM

Wow Schmitzi! How do you keep track of all this? 

BTW, I had no idea that the Regle a Calcul made an RS232 peripheral... I used to see a lot of ads for them in Jeux & Strategie back in the day and they used to have a TI inventory.



#6 --- Ω --- OFFLINE  

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Posted Wed Jun 20, 2018 7:20 AM

How difficult would it be to build such an interface for the TI-99/4A's sidecar expansion? .... Any suggestions?

 

If you have the "right" 32K expansion, you can go for the TIPI sidecar.

 

How difficult would it be to SIMULATE the RS-232 in software using a USB port on the TIPI's RPi?  Sure, the pinouts would not be the same, but functionality would be.



#7 FDOS OFFLINE  

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Posted Wed Jun 20, 2018 10:04 AM

Don't forget the UberGROM has a serial port as well usable with hdxs and timxt

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I've requested one that would include TI Basic with RXB's EA  support for TIB with Tursi's fixes that allows Basic programs in GRAM to create TIB enhancements in expansion memory using CALL INIT and BSCSUP, preloaded in GRAM/GROM 1 & 2.  I've not heard anything back, yet.



#8 Schmitzi OFFLINE  

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Posted Wed Jun 20, 2018 12:26 PM

Don't forget the UberGROM has a serial port as well usable with hdxs and timxt

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Yes, but this is the "Sidecar"-list. So here is the fully XFER/RS232/HDX-list:  ;)

 

Attached File  TI-99-4A-FULL-XFER-RS232-HDX-V1.00-beta.pdf   108.9KB   8 downloads



#9 Schmitzi OFFLINE  

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Posted Wed Jun 20, 2018 12:27 PM

 

Wow Schmitzi! How do you keep track of all this? 

...

 

Don´t know. Much time :)

 

Attached File  TI-99-4A-SW-Walid-Maalouli-v1.00-beta.pdf   45.97KB   5 downloads



#10 arcadeshopper OFFLINE  

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Posted Wed Jun 20, 2018 1:15 PM

 
I've requested one that would include TI Basic with RXB's EA  support for TIB with Tursi's fixes that allows Basic programs in GRAM to create TIB enhancements in expansion memory using CALL INIT and BSCSUP, preloaded in GRAM/GROM 1 & 2.  I've not heard anything back, yet.

Because it doesn't do g0/1 just cart rom and grom

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#11 Opry99er OFFLINE  

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Posted Wed Jun 20, 2018 1:16 PM

The most direct way to accomplish what the OP is asking for (small sidecar serial connection with storage) is the nanoPEB. You see em for sale either on eBay, arcadeshopper, or on here fairly regularly.

#12 arcadeshopper OFFLINE  

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Posted Wed Jun 20, 2018 1:16 PM

 
 
How difficult would it be to SIMULATE the RS-232 in software using a USB port on the TIPI's RPi?  Sure, the pinouts would not be the same, but functionality would be.

You'd need to write a DSR for the TI to talk to the pi

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#13 BeeryMiller OFFLINE  

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Posted Wed Jun 20, 2018 1:47 PM

You'd need to write a DSR for the TI to talk to the pi

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I am asking because I do not know.  Does the Raspberry PI itself support a USB to serial cable interface?



#14 arcadeshopper OFFLINE  

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Posted Wed Jun 20, 2018 1:56 PM

Yep pretty much any USB supported by the Linux kernel

 
I am asking because I do not know.  Does the Raspberry PI itself support a USB to serial cable interface?


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#15 FDOS OFFLINE  

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Posted Wed Jun 20, 2018 8:25 PM

Because it doesn't do g0/1 just cart rom and grom

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Yes, I know that.  I was asking for Tursi to preload the two RXB specific files that he fixed for me, because there is no loader for those addresses, yet.  I was hoping that once he has some spare time, he would do it.  In the mean time, I will try to fix my 80K GK or find out why my HSGPL card won't work with my F18A powered TI consoles.



#16 Opry99er OFFLINE  

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Posted Wed Jun 20, 2018 8:41 PM

What's wrong with your GK, Bill?

#17 jedimatt42 OFFLINE  

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Posted Thu Jun 21, 2018 3:35 PM

There is a sub-thread here about TIPI like substance and rs232...  

 

----

 

TIPI cannot be extended to add TI legacy compatible rs232 - there isn't room in the CPLD for the additional logic.  A TIPI board (all open sources design files) could probably be reprogrammed completely to provide 3.3v ttl serial at the back end that is TI legacy compatible. 

 

That is if you want to build something compatible with legacy TI rs232. 

 

----

 

A non-compatible rs232 could be extended if you wanted to use level 3 file IO, this wouldn't even require extending the DSR... Just adding a special file handler to the python side like I did to expose TCP to BASIC.

 

Then, python code to interact with the opening the serial device and queuing data to and from... 

 

If you wanted to just use the PI's additional GPIO pins... there is a catch: TIPI uses native code to work with GPIO, instead of python, you cannot use the additional pins from the python RPi library in the same process.  You'd have to add to libtipi/tipi.c   

 

If you enable the serial interface for the GPIO headers, you can probably use those directly from python as a character file device and just use python's open/read/write functions. Likewise, if you attach a usb-serial device... Using a usb-serial device is probably the easiest / cheapest way to get up to proper rs232 signalling. 

 

That is if, you wanted to build on TIPI. 

 

-M@



#18 FDOS OFFLINE  

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Posted Thu Jun 21, 2018 6:26 PM

What's wrong with your GK, Bill?

 

The two 8K RAM banks are not functioning.  They test ok, as I can FILL them with "0"s then "1"s.  I just can't load anything from disk in to them.



#19 FDOS OFFLINE  

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Posted Thu Jun 21, 2018 6:35 PM

You'd need to write a DSR for the TI to talk to the pi

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Nothing to do with serial talk between a TI & PI (maybe a slice of apple pie and a Big MAC?)  :)   FYI I just got my GOTEK working with my DSDD 8 track files.  I can copy files both ways using DM2K.  Nice.  ;)


 

Finally got my GOTEK working with my DSDD 80 track files.  I can copy files both ways using DM2K.  Nice. :)



#20 sparkdrummer OFFLINE  

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Posted Fri Jun 22, 2018 6:10 AM

Attached File  joytalk.jpg   1.47MB   5 downloads

 

99'er  June 1983



#21 Vinnie D. OFFLINE  

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Posted Fri Jun 22, 2018 2:49 PM

Ok, I want to say big thanks to everyone who replied. I got way more information than I ever expected, and it looks like this started some great discussions.  Looking at the options there's issues with all of them.

PEB: I don't want one.  Too big for adding one lousy port when I already have RAM, speech synth, and flash cart without one. Also much too expensive.
Sidecar: Very hard to find, also expensive

Nano PEB: Still kind of expensive, redundant with other things I already have, incompatible with most existing RS232 communication software, so no hooking a modem up to it.

Joy Talk: This is fascinating and affordable, but is entirely software driven, and it doesn't seem to have caught on, so again incompatible with existing software.

 

So the main reason I wanted an RS232 port is another project I'm working on. I found this http://subethasoftwa...an-rs-232-port/and thought, with a simple adapter this could easily be a universal wifi modem for any vintage computer, which the computer its self would see as a simple hayes modem, much the way the fairly common wifi modems for the C64 do. The design of course is for the Coco (which I'll be working on later), but an SIO adapter should be fairly simple for the Atari 8-bit line as well, so I thought why not try to fill that role with the TI-99 as well.

 

At the moment it looks like I've reached a brick wall.  The PEB or sidecar are the only things that would have existing software applications.  Of course there's the biggest obstacle which is (sorry to admit) I'm not that passionate about the TI-99.  You see I'm most into the C64, though I love vintage tech in general. The TI-99/4a I learned about while reading up on the history of Commodore (and Jack Tramiel's personal mission to kill it), and when I stumbled across one on eBay for $10 I thought, why not.  Though that's why I'm not really willing to drop $200 on a $10 machine. The accessories I do have, I largely bought because I caught them on the cheap.  I found an Eastern European seller producing RAM expansions for below the standard price, I caught someone selling out their old stock of flashrom99 carts and got one on the cheap, and lowballed auctions for the speech synth until one went through.  Yes I'm sorry to admit I'm a cheap bastard when it comes to the TI-99, but I still find it to be an interesting bit of computing history, and again thanks to all you much more passionate folks for all the info.

 

Anyway, back on topic. I've reached the conclusion for the time being my TI-99/4A will be a gaming system with no external connections, but I'll keep a look out for a sidecar, or updates to the nanoPEB that would improve compatibility.



#22 --- Ω --- OFFLINE  

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Posted Fri Jun 22, 2018 3:38 PM

@ Vinnie D.,

Your topic pointed out that there may be a market for a new Mini-RS-232 sidecar, if anyone needed a project or cared to create one. 

If one was to be made, I think a fully HDX compatible design would be best, that way those who obtained one would also able to save and load programs from their PC as well. 

 

Different users want different things for different reasons, with that in mind, having it as the first item off the side (like the speech synthesizer) would afford them the opportunity down the road to add additional items if they ever wanted to expand further.



#23 Opry99er OFFLINE  

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Posted Fri Jun 22, 2018 3:44 PM

I had thought about one as an add on card to Matt's 32k usingbthe header pins. Then TIPI came out and it sort of seemed redundant for 99% of users

#24 --- Ω --- OFFLINE  

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Posted Fri Jun 22, 2018 4:27 PM

I had thought about one as an add on card to Matt's 32k usingbthe header pins. Then TIPI came out and it sort of seemed redundant for 99% of users

 

Yes an add on for Matt's 32K would be cool, but Vinnie, like some others may not want dump a ton of money into their TI's, at least to start.  Having the RS-232 as a complete stand alone would increase the potential market.  People with internal 32K or even P-Box owners unwilling to drop a bunch of money for a older and harder to obtain  P-Box RS-232 could use it as well.

 

In my case, I've already purchased multiple 32K sidecar enclosures for the 32K and now the 32K and TIPI combo, I'll NOT be buying another replacement, but I would buy a single case for a RS-232 unit.



#25 Opry99er OFFLINE  

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Posted Fri Jun 22, 2018 4:59 PM

Right, but without 32k, what kind of terminal software are you planning to use?




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