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GPL Programmers Guide

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Here it is; a scan of the original GPL Programmers Guide by Texas Instruments.

Special thanks go to my belgian friend rocky007 who helped me in ordering, paying and shipping :)

The document sure makes an interesting read and is a nice enhancement to the TI-Intern book.

 

Enjoy!

 

  • GPL Programmers Guide PDF
    The original GPL programming reference manual from Texas Instruments. Covers all opcodes and advanced stuff like coincidence detection, I/O routines, etc.
     

    devres_ti_gpl_programmers_guide_book_cover.png


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Fantastic! Thanks for doing all that! IMO people who spend their own time and money to make something like this available for the community should at least get some donations. If you make a donation PayPal button, I'll definitely use it.

 

Matthew

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Great reading!

 

I was looking at the joystick and it has NEAR,MEDIUM and FAR returns for the joy stick. Do the TI joysticks support this or are they single bit joysticks? I have never use TI joysticks, I had the adapter to use Atari joysticks. That would be a nice feature in some games. It's a digital implementation or analog joysticks.

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TI joysticks are digital, on/off only, but in the original concept, they were going to have up to 3 bits of resolution in each direction, with the return values going from 0-7. The 99/4 ROMs contain some code for this, and is the only official reference of this design (I believe MESS implemented emulation of it, even though no real such joystick hardware has been found?). The real values are 0 or 4, if I had to hazard a guess I'd say that's MEDIUM. ;)

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TI joysticks are digital, on/off only, but in the original concept, they were going to have up to 3 bits of resolution in each direction, with the return values going from 0-7. The 99/4 ROMs contain some code for this, and is the only official reference of this design (I believe MESS implemented emulation of it, even though no real such joystick hardware has been found?). The real values are 0 or 4, if I had to hazard a guess I'd say that's MEDIUM. ;)

 

 

yeah, it specifies "returns 4,-4 if only using a single bit joystick"

 

other return values are 1,7,-1,-7.

 

It's neat that single bit joysticks provide 9 positions center, n,s,e,w,ne,nw,se,sw.

 

With this info you have 49 positions.

If you had the hardware specs for it you could create some complex controllers. Think about a platform controller that had a stick for left and right returning -7,-4,-1,0,1,4,7 for slow, walking and running speeds then mapping out 6 buttons for the y return of -7,-4,-1,1,4,7. You could have a jump button, a shoot button, a grab button, a grapple button, a duck button.

 

I've thought about combining 2 joysticks before, using jyst1 for moving and then adding buttons to it using jyst2. You could add 3 buttons to it with out conflicts. (Xon,Yoff),(Xon,Yon),(Xoff,Yon). This is a mod I would like to do with a sega genesis controller since it has 3 buttons and a start button, you can keep the start button triggered to the keyboard.

All it would take is the right pin outs, a crossover connector to plug the controller into then into the TI.

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www.ti994.com/timeline

 

JUNE 1979:

Texas Instruments introduces the TI-99/4 Home Computer at the June CES show in Chicago. At the show TI had wireless infrared keyboard and joystick peripherals ready to demonstrate to the public, however the presenters of the unit were told not to bring them out since the price of the 99/4 was now much higher than originally anticipated (first the TMS 9985 having to be replaced with the gold lead ceramic packaged TMS 9900 and then the rejection from the FCC on the modulator). Even though the wireless units were withheld from public viewing, the 99/4 that was shown still had the Infrared slot on the top of the casing.

 

BTW Thanks for the GPL manual. :)

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www.mainbyte.com/ti99

 

infared_port.jpg

 

Before the TI-99/4 was officaly released it was to come with remote I/R joysticks, and keypads. This was pulled at the last minute, and the above picture shows where the I/R device would have been mounted.

 

(upside down) :)

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If anyone would like to see more 99/4 inside photos, I made a gallery on my website containing detail shots from my own machine when I dismantled it. Seems like every 99/4 is slightly different though! :)

 

They are full resolution photos so you can see the details (although I watermarked the external shots to prevent people from using them on EBay ;) ). I figured there was not enough on the web about this machine!

 

http://harmlesslion.com/gtwo/v/Projects/ti994/

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That would be a nice project. Take a look here

 

www.nouspikel.com/ti99

 

I even think I saw that the original joystick design was going to be like wireless infrared control.

 

:)

 

I'm going to see if I can make it work. It will be my first hardware project for the TI.

Sega Genesis 3 button(really it's 4 button, start button) controller adapter for the TI.

 

I'll start a thread for it once I get all the pieces together.

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In section 1.7 "Applicable Documents" the "System Monitor Specification" is mentioned.

I believe this is refering to the TI-99/4A OS; does anyone know if this document is available somewhere ?

I'd sure love to get a scan of that one.

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