MBPII Modification

[Shift838]

I have been researching and working on a new version of the MBP card.  Dan Eicher graciously sent me his for me to compare to schematics that i have.  This one has a second 74LS138 that is piggybacked on IC10 (another 74LS138).  NOt sure what this is as it does not coincide with the digital output mod that uses a second 74LS08.

 

Does anyone what this mod is?

 

 

Edited August 11 by Shift838

[RickyDean]

1 hour ago, Shift838 said:

I have been researching and working on a new version of the MBP card.  Dan Eicher graciously sent me his for me to compare to schematics that i have.  This one has a second 74LS138 that is piggybacked on IC10 (another 74LS138).  NOt sure what this is as it does not coincide with the digital output mod that uses a second 74LS08.

 

Does anyone what this mod is?

 

 

Did you ever look into the info here?

 

[+9640News]

Just guessing, but could it be a GenMod Geneve modification?  I recall doing one to a card years ago.

[+InsaneMultitasker]

I can’t zoom in on the pics well enough from my phone, but I would guess this is address decoding to ensure the card only shows up on the external bus range of pages 0xB8 to 0xBF.

 

I think the MBP II card included the mod, but I no longer have my card to confirm this.    Regardless, the address decode is important since the card is not turned on and off by a CRU/enable, and will stomp on mirrors of the memory pages otherwise.  

[+InsaneMultitasker]

Here is an email I had kept on file from one of the hardware compendiums ~1994.  Note, the mod is not specific to the Genmod Geneves. Full compendium attached.

 

ti hardware compendium.txt

 

In case a reminder is needed, even a properly decoded MBP card will NOT respond in a Geneve system - neither in GPL/TI Mode nor Geneve mode - unless the external bus is mapped.  In other words, programs written for the MBP card will not work on a Geneve without intervention. 

 

---

 

DTIHM031

Modify the Rave Speech Card and MBP Card for use with the Geneve.
by Beery Miller

Item    7747642                 94/05/05        23:20
From:   BW.MILLER                       Beery W. Miller
To:     BW.MILLER                       Beery W. Miller
        COMP.SYS.TI.USENET@GATEKEEPER.DEC.COM@INET#
 
Sub: To: Markus Kraemer
 
Markus, here are the mods to the Rave Speech card and the MBP that permits
full decoding of those cards to work with the Geneve.  Any Geneve using one
of those cards without these mods are subject to PROBLEMS, PROBLEMS,
PROBLEMS.
 
The mods for the Geneve compatibility is as follows:
 
Solder pins 8 and pins 16 of a 74LS138 to pins 8 and 16 of 74LS138 on the
 card (this is for +5 volts and ground only, you may use another source if
 available), i.e. piggyback the chips.
 
Now for the decoding mod that properly decodes the Rave Speech card and the
 MBP card for full Geneve Compatibility (these devices will only respond at
 page >BC)
 
Cut the trace of pin 56 on the card near the bus connector
 
Pins of 74LS138
 _____________________________________________________________-
 
 1 Connect to bus pin 46
 2 Connect to bus pin 45
 3 Connect to bus pin 48
 4 Connect to bus side of bus pin 56
 5 Connect to bus pin 8
 6 Connect to bus pin 9
 7 Connect to component side of bus pin 56
 8 Connect to pin 8 of 74LS138
 16 Connect to pin 16 of 74LS138
 
(pins 9 through 15 are left disconnected)
 
These modifications are done at your own risk.  You assume all responsibilty
 for performing these modifications.
 

Edited August 12 by InsaneMultitasker
added full compendium document

[Shift838]

17 minutes ago, InsaneMultitasker said:

Here is an email I had kept on file from one of the hardware compendiums ~1994.  Note, the mod is not specific to the Genmod Geneves. Full compendium attached.

 

ti hardware compendium.txt 285.92 kB · 0 downloads

 

In case a reminder is needed, even a properly decoded MBP card will NOT respond in a Geneve system - neither in GPL/TI Mode nor Geneve mode - unless the external bus is mapped.  In other words, programs written for the MBP card will not work on a Geneve without intervention. 

 

---

 

DTIHM031

Modify the Rave Speech Card and MBP Card for use with the Geneve.
by Beery Miller

Item    7747642                 94/05/05        23:20
From:   BW.MILLER                       Beery W. Miller
To:     BW.MILLER                       Beery W. Miller
        COMP.SYS.TI.USENET@GATEKEEPER.DEC.COM@INET#
 
Sub: To: Markus Kraemer
 
Markus, here are the mods to the Rave Speech card and the MBP that permits
full decoding of those cards to work with the Geneve.  Any Geneve using one
of those cards without these mods are subject to PROBLEMS, PROBLEMS,
PROBLEMS.
 
The mods for the Geneve compatibility is as follows:
 
Solder pins 8 and pins 16 of a 74LS138 to pins 8 and 16 of 74LS138 on the
 card (this is for +5 volts and ground only, you may use another source if
 available), i.e. piggyback the chips.
 
Now for the decoding mod that properly decodes the Rave Speech card and the
 MBP card for full Geneve Compatibility (these devices will only respond at
 page >BC)
 
Cut the trace of pin 56 on the card near the bus connector
 
Pins of 74LS138
 _____________________________________________________________-
 
 1 Connect to bus pin 46
 2 Connect to bus pin 45
 3 Connect to bus pin 48
 4 Connect to bus side of bus pin 56
 5 Connect to bus pin 8
 6 Connect to bus pin 9
 7 Connect to component side of bus pin 56
 8 Connect to pin 8 of 74LS138
 16 Connect to pin 16 of 74LS138
 
(pins 9 through 15 are left disconnected)
 
These modifications are done at your own risk.  You assume all responsibilty
 for performing these modifications.
 

I think you are right.  now I wonder if this mod and the digital output that uses an extra 74LS08 can be on the card at the same time.  Anyone know?  I also think the card could have the geneve mod and still function in the TI or would it need a set of dip switches to enable and disable this mod?

 

 

Edited August 12 by Shift838

[+InsaneMultitasker]

1 hour ago, Shift838 said:

now I wonder if this mod and the digital output that uses an extra 74LS08 can be on the card at the same time

It may simply be a matter of figuring out where and how to add it so that it coexists with the decode mod.

 

Although I don't know the answer to your question, I can tell you that my MBP II was usable in my Geneve system, in /4a and 9640 modes.  I wrote general routines for Cecure to demo multi-channel output and record sound, but I wasn't interested in becoming the support person...

[+InsaneMultitasker]

With a quick search, I came across a 1994 iteration of my simple MDOS MBP II stereo file player's source but not the sound recording program. The player is branded with Cecure Electronics and refers to an old street address of mine, so I would want to redact personal info before and if I were to release anything. 

 

The two output ports are 8600 and 86C0; the MBP II docs should confirm this.

 

--

*
* playing structure
*
PLAYAG MOV  @PAGES,R5         total pages
       LI   R4,PGETBL+8       table of available pages

NXTPAG MOVB *R4+,@>F111       next page of data
       LI   R6,>2000          START OF BUFFER
       LI   R7,>4000          END OF BUFFER
       MOV  @PAUSE0,R8        PAUSE
MORE02 MOV  R8,R2             delay loop
MORE5  DEC  R2                done?
       JNE  MORE5             no
       INC  R9

       ABS  @STEREO           stereo?
       JEQ  LCHECK            no
       MOVB *R6+,@>8600  9A00 yes, send successive bytes to the channels
       MOVB *R6+,@>86C0  9A00
       INC  R9
       JMP  ENDOBUF           go check for end of buffer

LCHECK MOVB *R6+,R2
       ABS  @LEFT             left?
       JEQ  RCHECK            no
       MOVB R2,@>8600    8600 yes send to LEFT channel
RCHECK ABS  @RIGHT            was it right?
       JEQ  ENDOBUF           no
       MOVB R2,@>86C0    86C0 yes, send to right  - possibly same byte to both!

 

 

 

[+dhe]

@Shift838 - I love your connector with the pins labled to quickly see what pin you are tested.

[+9640News]

@InsaneMultitasker, thanks for pulling up my notes.  That is twice this year you recalled something I wrote and someone retained for the records.

 

Just some background for others.  With a non--expanded Geneve with stock memory, the MBP card would corrupt memory page >3C of the >00 to >3F page range as would the Rave Speech card.  This was due to not fully decoding the address lines.  Without fully decoding the address lines (no mod to the card), pages >3C, and any extra memory added pages, the additional pages including >7C and >BC would also have corrupt data as the MBP card would not bytes on all three of those 8K pages.  Page >FC would have been an issue, however there is never ram in that page range.

 

The mod described fixes the memory mapping for RAVE and the MBP cards.  There is another modification for other cards that do not map on the page >3A, >7A, and >BA mirrors.

 

Beery

[+InsaneMultitasker]

33 minutes ago, 9640News said:

 

@InsaneMultitasker, thanks for pulling up my notes.  That is twice this year you recalled something I wrote and someone retained for the records.

 

 

That’s what happens when you write “good things” 🙂

[Shift838]

The MBPII has the 34 pin edge connector on the back is used for digital output signals.  I'm wondering if I should replace that type of connector with a standard DSUB like DSub 25 since only 24 signals are mapped to the edge connector.

 

Thoughts?

 

[+InsaneMultitasker]

@Shift838 In addition to a connector (DSUB or some other), what about adding header pins like you see on the Rpi, so that you can connect to a block of inputs or outputs.  With some labeling for good measure.  Maybe add an rca jack similar with their own header pins, so you can decide how to set things up with jumpers or small cables.

 

The current edge connector is no fun to work with IMHO. 

[+dhe]

I'd vote for the db25... People could choose solder or modular, it also eliminates the plug in 180 backwards problem.

[Shift838]

4 minutes ago, InsaneMultitasker said:

In addition to a connector, what about adding header pins like you see on the Rpi, so that you can connect to a block of inputs or outputs.  With some labeling for good measure.  Maybe add an rca jack similar with their own header pins, so you can decide how to set things up with jumpers or small cables.

 

The current edge connector is no fun to work with IMHO. 

i like the idea for maybe a couple or so of RCA jacks and you could use jumper wires to connect digital output signals to. I may be able to fit a couple of RCA jacks along with a DB25..

Edited August 13 by Shift838

[Shift838]

I have been able to trace the connections between the back edge connector to the LS174's and the ADC0809 IC.  From all the documentation that Dan sent there is nothing in the docs of how to connect the edge connector to what you are trying to control.  I have also noticed on the documentation for the edge card connector that was sent the outputs are actually labeled backwards on the doc compared to what the datasheet for the LS174 is, not a big deal as I have the connections correct.

 

But for me to be able to understand how the digital output works I need to know who something would have been connected to the back card edge connector.  Does anyone know?

 

What I am showing in the doc for the edge card connector is below, but it differs to what it really is:

D = OUTPUT; U13/U14 = 74LS174

 

What documentation shows:

1 - Not connected

2 - Ground

3 - D0 U14

4 - Ground

5 - D5 U14

6 - Ground

7 - D1 U14

8 - INPUT 7 ADC0809 (PIN #5)

9 - D4 U14

10 - INPUT 6 ADC0809 (PIN #4)

11 - D2 U14

12 - INPUT 5 ADC0809 (PIN #3)

13 - D3 U14

14 - INPUT 0 ADC0809 (PIN #26)

15 - D0 U13

16 - INPUT 4 ADC0809 (PIN #2)

17 - D5 U13

18 - INPUT 1 ADC0809 (PIN #27)

19 - D1 U13

20 - INPUT 3 ADC0809 (PIN #1)

21 - D4 U13

22 - INPUT 2 ADC0809 (PIN #28)

23 - D2 U13

24 - +5VCC

25 - D3 U13

26 - 34 Not connected

 

What it actually is:

1 - Not connected

2 - Ground

3 - D5 U14

4 - Ground

5 - D0 U14

6 - Ground

7 - D4 U14

8 - INPUT 7 ADC0809 (PIN #5)

9 - D1 U14

10 - INPUT 6 ADC0809 (PIN #4)

11 - D3 U14

12 - INPUT 5 ADC0809 (PIN #3)

13 - D2 U14

14 - INPUT 0 ADC0809 (PIN #26)

15 - D5 U13

16 - INPUT 4 ADC0809 (PIN #2)

17 - D0 U13

18 - INPUT 1 ADC0809 (PIN #27)

19 - D4 U13

20 - INPUT 3 ADC0809 (PIN #1)

21 - D1 U13

22 - INPUT 2 ADC0809 (PIN #28)

23 - D3 U13

24 - +5VCC

25 - D2 U13

26 - 34 Not connected

 

 

 

[+Ksarul]

Here's a copy of the MBP-II manual I have. Look at page 7 to see how to use the analog inputs with a resistor network (at bottom of page).

 

MBPII.pdf

[Shift838]

10 hours ago, Ksarul said:

Here's a copy of the MBP-II manual I have. Look at page 7 to see how to use the analog inputs with a resistor network (at bottom of page).

 

MBPII.pdf 3.18 MB · 7 downloads

Thanks!  Does this image look right or do I have the variable resistor on the wrong side?

 

[Artoj]

13 hours ago, Shift838 said:

Does this image look right or do I have the variable resistor on the wrong side?

I did this schematic and board for testing my MPEB version, I hope this helps.

 

Schematic_TI99-ADC-TEST-V1_2024-08-15.pdf

[+Ksarul]

13 hours ago, Shift838 said:

Thanks!  Does this image look right or do I have the variable resistor on the wrong side?

 

Looks to match the manual, @Shift838, and you have the variable resistor in the correct place.

[Shift838]

Looks like I found an error in the remarks of the MBPII ADC Test program.

 

190 ! NOTE:
200 !   The pins of the card edge connector are numbered
210 !   from the top down on the component side of the
220 !   board as odd numbers. ie 1,3,5,7,...etc.
230 !   Pin # 1..No Connection
240 !   Pin # 3..No Connection
250 !   Pin # 5..+ 5 VDC
260 !   Pin # 7..Input Channel 2
270 !   Pin # 9..Input Channel 3
280 !   Pin #11..Input Channel 1
290 !   Pin #13..Input Channel 4
300 !   Pin #15..Input Channel 0
310 !   Pin #17..Input Channel 5
320 !   Pin #19..Input Channel 6
330 !   Pin #21..Input Channel 7
340 !   Pin #23..Ground
350 !   Pin #25..Ground

On the component side of the MBPII card it is actually numbered even and the inputs are on the back of the card:
 

What it actually is:

1 - Not connected

2 - Ground

3 - D5 U14

4 - Ground

5 - D0 U14

6 - Ground

7 - D4 U14

8 - INPUT 7 ADC0809 (PIN #5)

9 - D1 U14

10 - INPUT 6 ADC0809 (PIN #4)

11 - D3 U14

12 - INPUT 5 ADC0809 (PIN #3)

13 - D2 U14

14 - INPUT 0 ADC0809 (PIN #26)

15 - D5 U13

16 - INPUT 4 ADC0809 (PIN #2)

17 - D0 U13

18 - INPUT 1 ADC0809 (PIN #27)

19 - D4 U13

20 - INPUT 3 ADC0809 (PIN #1)

21 - D1 U13

22 - INPUT 2 ADC0809 (PIN #28)

23 - D3 U13

24 - +5VCC

25 - D2 U13

26 - 34 Not connected

 

Since I am not going to use the edge card connector, i'm going to try to fit a DB25 female and 2-3 RCA jacks long with a 14 pin header that someone can use jumper wires to jump grounds, 5v and inputs to the RCA jacks.

 

Thoughts?

[Shift838]

Been thinking.  I can fit 8 RCA jacks on the back of the PCB that would stick out of the back side of a PEB instead of a DB25 and a couple of RCA Jacks.

 

Each of the RCA jacks could then be directly wired to one of the Inputs (0-7) of the ADC IC.  What do all you TI'ers think would be best beneficially?  Looks like I can fit a DB9 or DB15 (3 row) or something similar as well to be able to get a ground, vcc and inputs 0-7 as well. I'm sure I can also put in a header to accommodate jumper wires for GND, VCC and Inputs 0-7.

 

I was thinking of using a right-angled RCA jack that is a 4x2 like:

PJRAS4X2U01AUX Switchcraft | Mouser

 

 

 

[Shift838]

Doing my final checks and I am wondering if the 9640 mod that is annotated in the attached image will still allow the MBPII card to function in the TI-99/4A without having to revert it.  I talking both the mods shown in the image, the for the AMA, AMB and AMC decoding as well as the clock speed slowdown or I may need to implement a pair of dip switches possibly to make it switchable for the TI-99/4A and Geneve.   The one that Dan loaned me has the AMA, AMB and AMC decoding but does not have the clock slowdown mod. I suspect the AMA,AMB,AMC mode will work in either TI or Geneve, but not sure about the clock slowdown.  I may just need a dip switch for that one.  Does anyone know for sure?

 

Edited August 21 by Shift838

[Shift838]

another thing I have been racking my brain about is if converting the ADC for inputs 0-7 is only needed then why was all the other signals connected to the 34-position card edge connector instead of just inputs 0-7, ground and +5v?  There are 12 other signals connected to the card edge connector that go to either U13 or U14.  Why would those be needed if we only need inputs 0-7, ground and +5v?  If those other signals are needed then the RCA jacks I am thinking won't work and I'll need just a cable header to be used of some sort.

[Gary from OPA]

2 hours ago, Shift838 said:

Doing my final checks and I am wondering if the 9640 mod that is annotated in the attached image will still allow the MBPII card to function in the TI-99/4A without having to revert it.  I talking both the mods shown in the image, the for the AMA, AMB and AMC decoding as well as the clock speed slowdown or I may need to implement a pair of dip switches possibly to make it switchable for the TI-99/4A and Geneve.   The one that Dan loaned me has the AMA, AMB and AMC decoding but does not have the clock slowdown mod. I suspect the AMA,AMB,AMC mode will work in either TI or Geneve, but not sure about the clock slowdown.  I may just need a dip switch for that one.  Does anyone know for sure?

 

Hmm. Not sure about the clock speed part.

 

But the ama/amb/amc address decode will work in both TI99 And geneve as the flexcable interface pulls those 3 extra address lines high.