Found these inside a non-working 71B

[Dave Frederickson]

(03-15-2018 05:09 PM)MikeSD Wrote:  If I said that, I must have been tired. I think the only place I used 10 is that the U9-9 is routed to the Math ROM-8 and also to pin 10 on U9, for some reason.

I noticed there is a Forth Assembler part number for "with and without" a debugger. My part number is for the with debugger. Wonder how I verify that? Is the debugger a hardware item, or another ROM, or part of the Assembler?

Mike,

You didn't call that part U10, I did. Schematically speaking, it needs a reference designator. U10 is just the next number in the series.

Yes, the F/A module was later marketed with a debugger, but it's software. The physical ROM is the same.

The IDS, however, mentions a hardware Debugger ROM several times. I suspect that U10 is where it was to be installed. Also of interest, the Service ROM contains a debugger very similar to the 82478A Debugger, but it's undocumented(!)

Dave

[Dave Frederickson]

(03-15-2018 05:09 PM)MikeSD Wrote:  Thinking out of the box
* I have a ton of 4K RAM boards, from salvaged 71Bs.
* And I have 4 unused front ports.
* And, I bet I could wire in some special connectors deep in those ports, to allow a kludged 8K RAM, made of 4K,
* to be inserted in and plugged into a special connector THAT wouldn't interfere with a standard plugin, if the RAM was removed.

Think that's possible? Can 8K RAMS be made, or do only 4K, 32K and 64K work as a group.

OR, I could put as many together as I could, that might fit in the Card Reader Port. Would like to find a good use for the 4K RAMs.

The key to that is being able to configure LCIM via the ID pin on the Saturn Bus to Memory Controller, except it's built into the HP 4k modules. You can put sixteen 4k modules together, but all you get is sixteen 4k ports, not a single 64k port.

The best use I've found for 4k modules is filling up front ports when selling a 71 on eBay.

Dave

[Paul Berger (Canada)]

(03-15-2018 05:09 PM)MikeSD Wrote:  If I said that, I must have been tired. I think the only place I used 10 is that the U9-9 is routed to the Math ROM-8 and also to pin 10 on U9, for some reason.

I noticed there is a Forth Assembler part number for "with and without" a debugger. My part number is for the with debugger. Wonder how I verify that? Is the debugger a hardware item, or another ROM, or part of the Assembler?

Thinking out of the box
* I have a ton of 4K RAM boards, from salvaged 71Bs.
* And I have 4 unused front ports.
* And, I bet I could wire in some special connectors deep in those ports, to allow a kludged 8K RAM, made of 4K,
* to be inserted in and plugged into a special connector THAT wouldn't interfere with a standard plugin, if the RAM was removed.

Think that's possible? Can 8K RAMS be made, or do only 4K, 32K and 64K work as a group.

OR, I could put as many together as I could, that might fit in the Card Reader Port. Would like to find a good use for the 4K RAMs.

The circuit board assembly used for the internal 4K modules is identical to the one used on the 4K front plug in module. This module is a hybrid composed of 4 1KB chips, but appears as a 4K module because only one chip reports "Last chip in module" so the OS treats them as a single unit of memory. In order to be able to get the OS to treat two as an 8K module would be to prevent the last chip of module one from reporting last chip then it would combine all the chips in the module with the chips in the next module on the daisy chain and the OS would then treat them as a single unit equal to the sum of all the chips in the combined modules. I don't know if this is possible with the 4K modules, but it certainly is not documented.

It would be possible to connect the modules to a front port or to stack some up in the card reader port. I have a specially constructed front port module that brings the bus lines out to a connector on the front that I initially built to monitor the bus, but recently have been using to test memory modules and it now has a 128K module attached to it that I am running looped diagnostics on. The card reader port is easier to connect to. The small size of the 4K modules makes them less attractive for front port or card reader port modules but they will work.

[MikeSD]

Thanks,
I'm not looking to build up huge memory modules or large port RAMS (but that would be useful). I was just looking to add more RAM to system. So I don't care that they are still considered separate modules. They can still be used as sys RAM . Just trying to find a good use for my 4K RAM boards.

I have a test jig too for bringing out stuff outside the 71B to test modules but I've misplaced it somewhere.

[Dave Frederickson]

(03-13-2018 07:17 PM)J-F Garnier Wrote:  The HHP card reader RAM modules (made of 32K boards) can be configured to create a 64K port from two boards. See here for instance (the link to the file is dead, use this instead).
Unfortunately, it is not possible (or not known) to do the same with 32K CMT modules -well it should be possible since the CMT01 programmer does it.

Referring to the pic in this post,

http://hpmuseum.org/forum/thread-10300-p...l#pid92701

I'll bet it has something to do with the blue wire going to pin 11.

Dave

[MikeSD]

(03-15-2018 07:09 PM)Dave Frederickson Wrote:  

(03-13-2018 07:17 PM)J-F Garnier Wrote:  The HHP card reader RAM modules (made of 32K boards) can be configured to create a 64K port from two boards. See here for instance (the link to the file is dead, use this instead).
Unfortunately, it is not possible (or not known) to do the same with 32K CMT modules -well it should be possible since the CMT01 programmer does it.

Referring to the pic in this post,

http://hpmuseum.org/forum/thread-10300-p...l#pid92701

I'll bet it has something to do with the blue wire going to pin 11.

Dave

I took a lot of pictures of that. I'll have to go back and see if I can find where it goes. Based on location it looks like OD/HALT I think. At least that's how I have it labeled on my partial schematic.

Mike

[Dave Frederickson]

(03-15-2018 10:12 PM)MikeSD Wrote:  Based on location it looks like OD/HALT I think.

OD and HALT are inputs to the 71 from the front ports. This pin on the CMT module would have to be an input to ID on the module's memory controller.

According to J-F's doc,

http://www.jeffcalc.hp41.eu/files/hhp96k.pdf

grounding the ID pin will disable LCIM and the module will be configured as a multi-chip module.

I suspect that the ID pin affects the LCIM bit on the first or second module only. If the pin is grounded then modules 1 and 2 or 2 and 3 get configured as a 64k port and if not then as three as 32k modules.

So, Mike, you might try connecting a short wire between pins 1 and 11 on the first module and see if you get a single 64k port.

Dave

[Paul Berger (Canada)]

If the "Disable Last Chip in Module" option is available on the CMT modules I don't think that it would be feasible to bring it out to one of the pads for a connector. These same modules are used in the CMT front plugin memory module. For default operation the "LCIM" pin is tied high. this would mean that if you used pin 11 which is OD in port 1 plugging the module into port 1 would disable the internal ROM. Pin 10 would not be useful either as it is int14 on all ports and is that pin is high it would always assert int14 which probably would not be good. Pin 13 can't be used either because on plugin modules it is expected top momentarily assert *INT. and when fully inserted this pin is grounded on the plugin side. Since it seem probable that the CMT EPROM programmer uses this function to switch between two 32K module and 1 64K module perhaps someone who has one of these could take a peek inside and see what the switch is wired up to.

I had taken apart a CMT front port module to wire it inside one of of my 71Bs and I preserved the shell and the connector pins. I just went and counted and there where 13 pins so they where contacts in the plugin for all 13 connections even though 2 of them are not used.

Paul.

[Paul Berger (Canada)]

(03-15-2018 10:40 PM)Dave Frederickson Wrote:  According to J-F's doc,

http://www.jeffcalc.hp41.eu/files/hhp96k.pdf

grounding the ID pin will disable LCIM and the module will be configured as a multi-chip module.

I suspect that the ID pin affects the LCIM bit on the first or second module only. If the pin is grounded then modules 1 and 2 or 2 and 3 get configured as a 64k port and if not then as three as 32k modules.

So, Mike, you might try connecting a short wire between pins 1 and 11 on the first module and see if you get a single 64k port.

Dave

Grounding the pin causes the chip it is grounded on to not turn on the LCIM bit in its config word this means that if the next module in the daisy chain has this pin high the capacity of the logical module will be the combined capacity of the two. This is how I observed it operating when I tried it on a HHP module I repaired and am now testing.

Paul.

[Sylvain Cote]

(03-13-2018 07:17 PM)J-F Garnier Wrote:  The HHP card reader RAM modules (made of 32K boards) can be configured to create a 64K port from two boards. See here for instance (the link to the file is dead, use this instead).
Unfortunately, it is not possible (or not known) to do the same with 32K CMT modules -well it should be possible since the CMT01 programmer does it.

Remember that the CMT-71-P01 is able to create a 64KB module (free ported RAM) only if the FORTH/Assembler module is present (page 3 of the Instruction Manual).
Sylvain

[Paul Berger (Canada)]

(03-16-2018 02:04 AM)Sylvain Cote Wrote:  

(03-13-2018 07:17 PM)J-F Garnier Wrote:  The HHP card reader RAM modules (made of 32K boards) can be configured to create a 64K port from two boards. See here for instance (the link to the file is dead, use this instead).
Unfortunately, it is not possible (or not known) to do the same with 32K CMT modules -well it should be possible since the CMT01 programmer does it.

Remember that the CMT-71-P01 is able to create a 64KB module (free ported RAM) only if the FORTH/Assembler module is present (page 3 of the Instruction Manual).
Sylvain

That is because of a bug in the OS that may be fixed in a later version, it is still possible but if when it is freeported if it ends up at the top of memory it will be unusable.

[Dave Frederickson]

Okay,

With the CMT-71-P01, when the switch is in the 32k position, I measure 6.49V on Pin 11, with the blue wire. When in the 64k position I measure zero.

(03-16-2018 02:04 AM)Sylvain Cote Wrote:  Remember that the CMT-71-P01 is able to create a 64KB module (free ported RAM) only if the FORTH/Assembler module is present (page 3 of the Instruction Manual).
Sylvain

The manual states,

To use the programmer in the 64K mode, a FORTH/ASSM ROM needs to
be inserted into another HP-71 port.

There's no problem creating a 64k port without the F/A ROM, see below.

Code:


/* This is the 2CDCC machine I have hooked up to the P01 in Port(4).
>SHOWPORT
0.05  16384  2
0      4096  0
0.01   4096  0
0.02   4096  0
0.03   4096  0
4     65536  0 \* The switch is in the 64k position
5     32768  0 \* CMT 128k RAM
5.01  32768  0
5.02  32768  0
5.03  32768  0
>
>FREEPORT(4)
>
>MEM(4)
 65531 \* Port created
>
>VER$
HP71:2CDCC HPIL:1B \* No F/A
>
\* Switching to 1BBBB with the 64k bug
>VER$
HP71:1BBBB HPIL:1B
>
>
>SHOWPORT
0.05  16384  2
4     65536  1 \* IRAM is still there because the P01 is still powered
>
>CLAIMPORT(4)
>SHOWPORT
0.05  16384  2 \* P01 RAM is now in MAIN
>
>FREEPORT(4)
>MEM(4)
 65531 \* FREEPORT okay
>

An additional description of the bug can be found in the 1985 Atlanta Conference Proceedings, pp103-104, in an article by Jim De Arras from HHP, describing the discovery of the bug when he first delivered the 64k modules to HP.

The bug is easy to duplicate with Emu71. As described in the article, it occurs when EDIT is invoked on a 64k IRAM configured at E0000.

Dave

[J-F Garnier]

(03-15-2018 10:40 PM)Dave Frederickson Wrote:  According to J-F's doc,
http://www.jeffcalc.hp41.eu/files/hhp96k.pdf
grounding the ID pin will disable LCIM and the module will be configured as a multi-chip module.

I named this pin ID because it affects the response of the chip to the C=ID opcode.
Of course I didn't know the actual name of the pin, and LCIM would be a better name.
I suspect that other pins are defining the memory type and size, and thus the global response of the chip to C=ID.

J-F

[Dave Frederickson]

(03-16-2018 01:55 AM)Paul Berger (Canada) Wrote:  If the "Disable Last Chip in Module" option is available on the CMT modules I don't think that it would be feasible to bring it out to one of the pads for a connector. These same modules are used in the CMT front plugin memory module. For default operation the "LCIM" pin is tied high. this would mean that if you used pin 11 which is OD in port 1 plugging the module into port 1 would disable the internal ROM. Pin 10 would not be useful either as it is int14 on all ports and is that pin is high it would always assert int14 which probably would not be good. Pin 13 can't be used either because on plugin modules it is expected top momentarily assert *INT. and when fully inserted this pin is grounded on the plugin side. Since it seem probable that the CMT EPROM programmer uses this function to switch between two 32K module and 1 64K module perhaps someone who has one of these could take a peek inside and see what the switch is wired up to.

I had taken apart a CMT front port module to wire it inside one of of my 71Bs and I preserved the shell and the connector pins. I just went and counted and there where 13 pins so they where contacts in the plugin for all 13 connections even though 2 of them are not used.

Paul.

Realize that if you try this mod on a front-port module you may need to cut a trace. As this discussion pertains to the internally wired modules there's no connection between Pin 11 on the memory module and the ports of the 71.

Not sure what the issue is with Pin 13, GND, momentarily asserting *INT. Is that the "Module Pulled" mechanism?

Dave

[Paul Berger (Canada)]

(03-16-2018 03:19 PM)Dave Frederickson Wrote:  

(03-16-2018 01:55 AM)Paul Berger (Canada) Wrote:  If the "Disable Last Chip in Module" option is available on the CMT modules I don't think that it would be feasible to bring it out to one of the pads for a connector. These same modules are used in the CMT front plugin memory module. For default operation the "LCIM" pin is tied high. this would mean that if you used pin 11 which is OD in port 1 plugging the module into port 1 would disable the internal ROM. Pin 10 would not be useful either as it is int14 on all ports and is that pin is high it would always assert int14 which probably would not be good. Pin 13 can't be used either because on plugin modules it is expected top momentarily assert *INT. and when fully inserted this pin is grounded on the plugin side. Since it seem probable that the CMT EPROM programmer uses this function to switch between two 32K module and 1 64K module perhaps someone who has one of these could take a peek inside and see what the switch is wired up to.

I had taken apart a CMT front port module to wire it inside one of of my 71Bs and I preserved the shell and the connector pins. I just went and counted and there where 13 pins so they where contacts in the plugin for all 13 connections even though 2 of them are not used.

Paul.

Realize that if you try this mod on a front-port module you may need to cut a trace. As this discussion pertains to the internally wired modules there's no connection between Pin 11 on the memory module and the ports of the 71.

Not sure what the issue is with Pin 13, GND, momentarily asserting *INT. Is that the "Module Pulled" mechanism?

Dave

My curiosity got the better of me and I looked inside my modded 71B and on the three modules inside, one of which I know for sure came from a CMT 32K front plugin and the other two look identical there is nothing connected to pin 11, and there is no obvious place to connect to LCIM, so the modules in the EPROM programmer must be different or modified since you say the switch is connected to pin 11. These modules also look the same as the ones that Mike posted the pictures of.

I meant pin 12 *int not 13 which is ground.

Paul.

[Dave Frederickson]

(03-16-2018 09:05 PM)Paul Berger (Canada) Wrote:  

(03-16-2018 03:19 PM)Dave Frederickson Wrote:  Realize that if you try this mod on a front-port module you may need to cut a trace. As this discussion pertains to the internally wired modules there's no connection between Pin 11 on the memory module and the ports of the 71.

Not sure what the issue is with Pin 13, GND, momentarily asserting *INT. Is that the "Module Pulled" mechanism?

Dave

My curiosity got the better of me and I looked inside my modded 71B and on the three modules inside, one of which I know for sure came from a CMT 32K front plugin and the other two look identical there is nothing connected to pin 11, and there is no obvious place to connect to LCIM, so the modules in the EPROM programmer must be different or modified since you say the switch is connected to pin 11. These modules also look the same as the ones that Mike posted the pictures of.

I meant pin 12 *int not 13 which is ground.

Paul.

At the moment I can neither confirm nor deny that the P01 modules are custom. Examining the pics in Posts #3 and #4 of this thread, the modules certainly look identical from the top side.

When you say nothing is connected to pin 11, you verified this visually or with an ohmmeter?

Dave

[Paul Berger (Canada)]

Visually with a USB microscope its only a double sided board, I also grounded pin 11 and it did nothing.

Paul.

[Dave Frederickson]

(03-16-2018 11:50 PM)Paul Berger (Canada) Wrote:  Visually with a USB microscope its only a double sided board, I also grounded pin 11 and it did nothing.

Paul.

Paul, you're absolutely right! The CMT module has been modified. The "LCIM" signal comes up from the PCB to pin 11. The blue wire is connected from pin 11 to a via next to a cut trace on the bottom side of the memory module. This is undoubtedly connected to the ID pin on the memory controller and the cut trace is likely VCC.

If anyone is interested in performing this mod I can provide a pic of the cut trace and via.

On an unrelated note, on which USB microscope did you settle?

Dave

[MikeSD]

Shoot me a pic of the mod. I'll check try it when I get this system working.

Not a good day today. I can't seem to get the FORTH ASSEMBLER working. As soon as it's connected, everything shuts down. No display.

I'm going to go back and look at everything tomorrow, for shorts or breaks. Or forgotten wires. Nothing buzzed wrong. Everything looks ok, but the system dies, if it's connected. I have pics of everything as I got it. And the hookup is pretty straight forward. I must have forgotten something.

I'm only using, for the moment, pins 1-7 and pin 8 from the RAM, for Daisy In. I also have the ground pin connected. I'm leaving off the Daisy Out to the HPIL for time being. That's how it was when I got it, best I can tell.

I'm also going to look for any potential breaks on the FORTH board.

Tomorrow's another day. Everything working fine now, but the FORTH. Will suck if that's the one chip not working. So far, everything has been caused by broken wires, and operator error (me).

I may put the FORTH alone, back in my test 71B and see if it works there. Also might just hook it up to one of the ports and see if it works there.

[Paul Berger (Canada)]

(03-17-2018 12:20 AM)Dave Frederickson Wrote:  

(03-16-2018 11:50 PM)Paul Berger (Canada) Wrote:  Visually with a USB microscope its only a double sided board, I also grounded pin 11 and it did nothing.

Paul.

Paul, you're absolutely right! The CMT module has been modified. The "LCIM" signal comes up from the PCB to pin 11. The blue wire is connected from pin 11 to a via next to a cut trace on the bottom side of the memory module. This is undoubtedly connected to the ID pin on the memory controller and the cut trace is likely VCC.


If anyone is interested in performing this mod I can provide a pic of the cut trace and via.

Yes please, and I am pretty sure M. Garnier will be interested as well.

(03-17-2018 12:20 AM)Dave Frederickson Wrote:  On an unrelated note, on which USB microscope did you settle?

Dave

I got an Andonstar, the silver tube model, I see they have some others now including one that has a tiny screen built in. It works pretty good but the stand is a bit shaky, jumps around a bit much when you are trying to focus or adjust height. I have yet to try building under it but I do think it will work ok.

Paul.