MiniWriter 3 cart (with novel, integrated parallel interface)

[blakespot]

This thing is pretty interesting.

 

http://www.hexbus.com/TI-99_4A_Home_Computer_Page/Cartridge_Pictures.html#16

 

Does anyone have a photo of this cracked open? Id love to see how its pit together. Can the TI write (output) to the cart port? Hmmm....trying to recall if MiniMemory is a command module or a side attach cart. Maybe the whole bus is exposed on that cart connector.

 

Im intrigued.

[+mizapf]

No, there is only A3-A15 of the address bus, limiting the addressable space to 8K. And the ROMG line is set when the address is between 6000 and 7fff. However, there is no restriction for writing; you can put whatever you want inside that space. Unless you are using a QI console, you even have ports via CRU.

[+acadiel]

I know of the following versions:

 

Miniwriter

Miniwriter II

Miniwriter III

Miniwriter III+

 

I'd love to know:

1) Differences between these

2) Specs on the cable that was used to hook up to them

 

I'll see if I can split mine apart to give you some pictures.

[sparkdrummer]

I've got a couple of those carts as well - I'd like to know what the pin outs are for a printer as well.

[+Schmitzi]

IIRC, once I saw a " Miniwriter II + " (with PIO-header) on eBay, it went for $13,50

[+Ksarul]

The "+" variants were supposed to be the ones with the integral printer port, but DataBioTics didn't always use the labels that way (I have seen a lot of the ones without the PIO ports labeled as Miniwriter III+ or Miniwriter II+. I have to double check, but I think I have all four types. The original Miniwriter was a tape/disk for the Mini Memory, not a cartridge. Later iterations from this code base were the Wordwriter, Wordwriter Xtra, and Beyond Wordwriter cartridges. Further development was planned and announced, but never came to pass.

[+InsaneMultitasker]

I am pretty sure I have the source code to one or more versions of this cartridge. I'll poke around for the disk images and post them (if I find them) when I have time.

[+acadiel]

Here’s my Miniwriter III. Label is falling off.

 

[+acadiel]

Here’s my III plus

 

[+acadiel]

16 pins connected out of the 20. Probably pretty close to a PBox PIO cable, but need someone to dig out a cable so we can pin out it.

[Opry99er]

Wow. I have seen pictures of these carts, but never in this much detail. Thanks for the pics!!

[Count9929A]

Hi, I have MiniWriter I on tape (original), but I don't have the manual. I have a pdf of the MiniWriterII manual.

Does anyone know the differences between the two versions?

[Ed in SoDak]

What format are the files? Standard DV/80 such that TI-Writer could load/save them? Or is it some cassette-only format? Still, oughta be a BASIC loader for that. Does the printer only accept output created by Miniwriter or can other programs access the printer through the cart?

 

In other words, is there any usefullness to them other than the original intended purpose of printing what you just wrote? It would just be a collector cart for most of us unless it had broader uses.

 

Jes' curious.

-Ed

[+OLD CS1]

My guess is the printer port is memory-mapped in the cartridge space, something simple. DBT used CRU bank switching in its cartridges but, with the exception of later models, the circuitry does not look complex enough for that.

[blakespot]

My guess is the printer port is memory-mapped in the cartridge space, something simple. DBT used CRU bank switching in its cartridges but, with the exception of later models, the circuitry does not look complex enough for that.

 

Do you imagine that outputting to the printer was writing to that address space and that data was the datastream for the printer? Or do you think somehow reading a certain section of data was what caused the data stream -- where a read access is handled as a signal to output data. Doesn't looks complex enough for me. I guess I'm just coming from the notion that you can't write to the cartridge port. But then, I guess there's MiniMemory, though, right?

 

 

bp

[+Ksarul]

You can definitely write to the cartridge port space. Every single bank-switched cartridge from Extended BASIC on relies on it to initiate a bank switch. It is part of the original hardware specification for the TI.

[+InsaneMultitasker]

If this is indeed the same code, it looks like there is both a read and a write address on the cartridge.

 

The folder that -should- have contained WordWriter/MiniWriter source is empty but I found a nearly complete set of code from which this excerpt was copied. I'll have a look through my disks another day, on the off-chance I still have the originals.

 

Edit: Read from port: 7ffc; write to port 7ffe.

 

 

 

*
************************************
* V1.7 MINIEDITOR *
* COPYWRITE 1984 MODEL MASTERS *
* 5/04/84 *
* PROGRAMMED BY W. R. MOSEID *
* FOR THE MINI MEMORY *
* REVISED BY J TRINKL 10/20/86 *
* TO BECOME MINIWRITER II & III *
* FOR ROM BASED EXECUTION *
************************************

 

* 9/26/85 9/30/86
***************************************
* PRINT TO PARALLEL *
***************************************
CR EQU CMDTBL
LF EQU C10+1
JSMSG1 TEXT ' PRINTING'
EVEN
JOY2 MOV R11,*R10+
MOV @>7FFC,R0
CI R0,>FAFA
JEQ PREND1
MOV @LINE,@PRLINE SAVE LINE PNTR
PRLB0 ORI R7,>0001 8/13 Set print flag
BL @VMBW1
DATA 0
DATA JSMSG1 GET MSG PNTR
DATA 9 GET MSG LENGTH
BL @CLRLIN CLEAR LINBUF
CLR @LINE CLEAR LINE PNTR
PRLB1 INC @LINE LINE PNTR = LINE PNTR + 1
C @LINE,@LINNO HAVE WE SENT ALL TEXT BUFFER LINES?
*
*<-*******************************************
*
JEQ MORE3
*
*<-*******************************************
*
JGT PREND YES-EXIT
PRLB2 BL @KSCAN GET KB INPUT
CB @KEYCAN,@CHAR COPY FLAG REGISTER
JEQ PREND CHECK IF CANCEL CMD
BL @RTEXT NO-READ A LINE
*
LI R9,LINLEN
MOV *R9+,R8
OUTCHR CLR R2
MOVB @>7FFC,R2
ANDI R2,>0100 PRINTER BUSY?
JNE OUTCHR JMP=YES
MORE MOVB *R9+,@>7FFE PRINT BYTE
MORE1 MOVB @>7FFC,R2 PRINTER BUSY?
ANDI R2,>0100
JNE MORE1
DEC R8
JNE MORE
MOVB @LF,@>7FFE LINE FEED
MORE2 MOVB @>7FFC,R2 PRINTER BUSY?
ANDI R2,>0100
JNE MORE2
MOVB @CR,@>7FFE CARRIAGE RETURN
JMP PRLB1 CONTINUE
PREND MOV @PRLINE,@LINE RESTORE LINE PNTR
ANDI R7,>FFFE 8/13 RESET CHAIN AND PRINT FLAGS
PREND1 B @ENDALL

 

MORE3 BL @RTEXT READ LAST LINE
LI R4,MORE4 8/7 Get Chain Print Req return
BL @CK1CF Check for Chain Print
JMP PRLB2 No - continue
MORE4 BL @MOVNAM Left justify name in LINBUF
ANDI R7,>DFFF Set LOAD flag
LI R13,PRLB0 FILERR RETURN
BL @FILLB0 Read in file

Edited May 13, 2018 by InsaneMultitasker

[Opry99er]

Isn't this the way to re-flash/update the XB2.7 cartridge?

[+acadiel]

Item #1: Coming back to this thread.. about making a printer cable, in some circles, I've seen pins 1-16 on the PIO port hooked to pin #1-16 of the Centronics 36 pin connector. However, I'm not finding a guide on the TI's 16 pin PIO port of how to connect from PIO to the Centronics 36 connector, and which pins need to be omitted or changed. Attached is a side by side pinout of the Centronics on the left and the TI PIO on the right.

 

Item #2: The MiniWriter port is 20 pins on the edge card. But if you look at the last 3 (18-20), they're ground (or positive - I haven't metered it - along with one on the other side). 12 others are connected, and 8 of those are parallel data lines. That leaves four control lines. I'm assuming that whomever made the Centronics cable for this wanted to keep it simple, so I'm wondering if we can crowd source the pinout here as well.

 

Anybody have a #1 they can crack open and trace the pins? I am aware there were different pins; I probably want an Epson compatible cable if someone has one. If you have a different brand, it'd be kind of cool to pinout those too just to have them for reference.

 

Same with #2. If someone has the cable, I have some 20 pin EDGE connectors (I just need to get some Centronics 36 male IDCs) and some ribbon cable and my crimper.

[+acadiel]

Isn't this the way to re-flash/update the XB2.7 cartridge?

 

 

Actually, XB 2.7 was a bit of a hack, so Tursi's UberGROM recovery won't work. Best bet is to use an EEPROM programmer to reprogram the 1284P.

[+Ksarul]

IIRC, there was only one printer cable made for these cartridges. I think I may have an original cable for it with one of mine with the printer connector. . .

[+acadiel]

IIRC, there was only one printer cable made for these cartridges. I think I may have an original cable for it with one of mine with the printer connector. . .

 

Cool! I have some male IDC 36 pin Centronics connectors coming in from China, and got some 20 pin EDGE ones from UXCell on Amazon, and plenty of ribbon cable in a pack... so I can try it out once I get a pinout.

 

Those Centronics IDC connectors are around $5/ea and the 10 pack of EDGE connectors was $7.50. Plus ribbon cable. I can probably make cables for people that have these because I'll have eight of the EDGE IDC's left. Just would have to order more Centronics ones on demand.

[Opry99er]

So who wants to do a board run for MiniWriter3?

[+Ksarul]

You'd need a copy of the PAL coding to do a board run of these. . .

[Opry99er]

I was at least partially joking. I think we have little need for this cartridge these days.... but the novelty is pretty high. What a cool piece of history!