Yes, I have an LCDS

[Realtime]

Over on the NIBBLER thread I mentioned that I have a National Semiconductor Low Cost Development System (LCDS) and Craig@Helloworld asked for some info. I thought a new thread would be a good place to point to previous LCDS threads and hopefully get other LCDS owners to give some details on what equipment they have. It would be great to get a fuller picture of what's out there.

• Hardware - base unit (Eurocard or US version), cards, accessories
• Software - NIBL and SUPAK seem to be the 2 prime applications for the LCDS. Were there others?
• Documentation - Hardware & SW manuals, Application Card manuals, schematics, etc
• Condition - Working, non-working, don't know?
• What do you do with it or is it just part of your collection?
• Information you're looking for

So, I'll make a start.

I bought my LCDS in 2023.
Hardware:
Eurocard format LCDS (1976), SC/MP I Application Card (APC), SC/MP II APC, 4K SRAM APC. I subsequently designed and built a 4K MM5204-EPROM APC and a 64K EPROM/RAM/Serial Interface module.
It also came with a TELEKIT hand held terminal (20mA loop interface), which turned out to be a prototype of a productionised Gleichmann Pocket Terminal.
Software:
Other than the on-board debugger and monitor there was no specific SW provided. I have Kitbug+ and NIBLE installed in EPROM, with Kitbug++ next on the list.
Documentation:
LCDS user manual original and expanded versions (both targetting the US hardware - was there ever a Eurocard version?) plus a few SC/MP datasheets. I also have the processor APC and ROM APC pamphlets (again US versions - have never seen the Eurocard versions)
Condition:
It was non-working when I received it. Didn't take too long to get the base unit up and running. Most of my efforts were put into getting the TELEKIT running.
What do I do with it?
Exhibited it at CFCH Retrofest in Nov 23 and Nov 24

and got some interest. It gets a lot of use for testing new SC/MP hardware projects, debugging code, running SC/MP monitors and was central in developing the TELEPIC replica.
Items I want:
Really, anything LCDS but specifically

• the SC/MP Emulation Card (SEC). Never found any real info on this but it was advertised by Nat Semi around 1977 and included in a list of equipment considered as the minimum needed for a development system.
• the PROM Programmer, which I gather could program MM5204's as well as Bipolar proms.
• EUROCARD version documentation. Apart from the schematic available on the BIT Savers site everything seems to be US orientated. Apart from the APC pinouts there are other substantial differences between the US and Eurocard versions of cards, so it would be great to find the Eurocard schematics.

Originally Posted by HelloWorld

I have made a first attempt at recreating the CPU application card and it is at the board fab house now. Do you have the documentation for the CPU application card?

I'm assuming you have the US version LCDS (?) Did you know someone has already produced a Processor APC replica? Gerbers are here and schematics here. However if it's the Eurocard data you're looking for then (as stated above) I'm also in the dark, but at least I have one

Originally Posted by HelloWorld

Victoria Museum has complete system and documentation.. including for the LCDS application card... but seem unwilling to share. They must be flush with cash because my offer to pay all costs plus a contribution evidently did not merit a response.

I contacted VMA about a year ago. They were very helpful but said they currently didn't have a Curator of Computing Technology and the person addressing my request didn't have much knowledge of the subject. Perhaps that is still the case and enquiries take a bit of time to get a response.

Regards
Ian

[Mark1960]

Does the application card have the functions for debug of scmp programs or is that on the emulation card? I’d be very interested in building a replica with the debug functions included.

[HelloWorld]

Originally Posted by Realtime

I'm assuming you have the US version LCDS (?) Did you know someone has already produced a Processor APC replica? Gerbers are here and schematics here. However if it's the Eurocard data you're looking for then (as stated above) I'm also in the dark, but at least I have one

I contacted VMA about a year ago. They were very helpful but said they currently didn't have a Curator of Computing Technology and the person addressing my request didn't have much knowledge of the subject. Perhaps that is still the case and enquiries take a bit of time to get a response.

Regards
Ian

I picked up a US version of the LCDS earlier in the month, but it did not have any cards. I did find those schematics you referenced, but i did a layout from scratch because i wanted to add a serial port and some other mods. I have that schematic and the LCDS user's manual that is on bitsavers.

I have received a response from museum victoria since my last post, but i am not sure that i am making any progress.

can i get a copy of the application card user's guide pamphlet?

thanks
craig

[Realtime]

Originally Posted by Mark1960

Does the application card have the functions for debug of scmp programs or is that on the emulation card? I’d be very interested in building a replica with the debug functions included.

No, the Processor APC is pretty basic (see attached). The debug / single stepping is performed by the LCDS hardware and the Emulation Card apparently handles the arbitration between the LCDS and target hardware. The Emulation Card can be set up to define target and user memory areas using dip switches.

[HelloWorld]

Originally Posted by Realtime

Items I want:
Really, anything LCDS but specifically

the SC/MP Emulation Card (SEC). Never found any real info on this but it was advertised by Nat Semi around 1977 and included in a list of equipment considered as the minimum needed for a development system.

In addition to the application card, can you share the NS advertisement for the emulation card so i can start digging into that?
thanks
craig

[newlite4]

This looks very similar to the Mini Micro Designer of the same era. I made up five of these in 1980 at work to be installed in research machinery. These came with 1kb of memory and were a popular low cost system add-on at the time.
Neil

[Mark1960]

Originally Posted by newlite4

This looks very similar to the Mini Micro Designer of the same era. I made up five of these in 1980 at work to be installed in research machinery. These came with 1kb of memory and were a popular low cost system add-on at the time.
Neil

Was it this one?
https://archive.org/details/manual_revl/page/19/mode/2up

[newlite4]

Yes Mark, that's the one. One of the MMDs was adapted to operate with just five waterproof buttons to fit on a tractor. Rugged little things.
Neil

[Realtime]

[QUOTE=HelloWorld;1731351]

Originally Posted by Realtime

Items I want:... can you share the NS advertisement for the emulation card so i can start digging into that?

I've searched high and low through my LCDS downloads and data snippets and haven't been able to find the source of that diagram (the annotations are my own). The only other concrete thing I know is that the part number is ISP-8C/806, which probably appeared in a Nat Semi advert or newsletter

[HelloWorld]

[QUOTE=Realtime;1731094]

I'm assuming you have the US version LCDS (?) Did you know someone has already produced a Processor APC replica? Gerbers are here and schematics here. However if it's the Eurocard data you're looking for then (as stated above) I'm also in the dark, but at least I have one

I had some of these LCDS CPU application boards made and just received the bare boards but have not tested...( i just downloaded the gerbers that Lucien posted on vcfed and submitted the files to the board house).. if anyone in the US wants one of these, drop me a line. Selling at cost which is $8 plus shipping.

[HelloWorld]

[QUOTE=HelloWorld;1732711]

Originally Posted by Realtime

I had some of these LCDS CPU application boards made and just received the bare boards but have not tested...( i just downloaded the gerbers that Lucien posted on vcfed and submitted the files to the board house).. if anyone in the US wants one of these, drop me a line. Selling at cost which is $8 plus shipping.

As an update, I have Lucien's reproduction LCDS CPU application board built and tested. Is Lucien on this forum?

With a couple of address jumpers and a TTL serial port connected to the edge connector, it seems to be running kitbug++ just fine. But KitBug++ consumes a huge chunk of the 256 bytes of RAM. National's original kitbug or Phil's kitbug plus may be a better option if you are planning to use it for any big work.

Links to schematics and his gerber build files are in Realtime's post above.

The 74LS00 he added NANDs the /MEMSELECT and ROMSELECT to the enable the 2732. To get the board to run on it's own----> Map the ROM to A12=0 by connecting A12 on p55 to the input of the unused inverter on p61 (ENI), and the output of that inverter (/ENI on p62) to ROMSEL on p64. Map the RAM to A12=1 by connecting A12 to RAMSELECT on p63. This board does not have any buffering or inverters on the Flag and Sense. My latest version of kitbug has an assemble time switch to enable or disable inversion of the FLAG0 output.

[Realtime]

That's great. So that means your LCDS is up and running, or are you still testing stand-alone currently? It's good to see another LCDS being brought back to life. Can you post a few photos of the processor board and LCDS?

Regarding Kitbug++, I had it up and running on the LCDS this morning with ROM at $4000 and RAM at $2000. All good as far as I could tell. I was going to mod it for 110 baud, but decided to leave it at 1200 baud (SC/MP I processor) and use the already resident Kitbug+ if I want 110 baud for the TELEKIT.

[HelloWorld]

Originally Posted by Realtime

That's great. So that means your LCDS is up and running, or are you still testing stand-alone currently? It's good to see another LCDS being brought back to life. Can you post a few photos of the processor board and LCDS?

Regarding Kitbug++, I had it up and running on the LCDS this morning with ROM at $4000 and RAM at $2000. All good as far as I could tell. I was going to mod it for 110 baud, but decided to leave it at 1200 baud (SC/MP I processor) and use the already resident Kitbug+ if I want 110 baud for the TELEKIT.

I haven't even started looking at my LCDS. I am just running the application board flat on the bench. Honestly i haven't even looked if it is the SC/MP I or SC/MP II version.

I had two application boards in this board order. One is the version i made which has a header for power and serial as well as a reset button. then at the last minute i added Lucien's board from the vintage computer forum to the order.

Two photos attached. the one with the connector on the card edge is Lucien's and the one on the right with 6 pin header at the top is my version.

I will get to looking at the LCDS when I get my instruction jamming circuit board done.

[HelloWorld]

Originally Posted by Realtime

That's great. So that means your LCDS is up and running, or are you still testing stand-alone currently? It's good to see another LCDS being brought back to life. Can you post a few photos of the processor board and LCDS?

Regarding Kitbug++, I had it up and running on the LCDS this morning with ROM at $4000 and RAM at $2000. All good as far as I could tell. I was going to mod it for 110 baud, but decided to leave it at 1200 baud (SC/MP I processor) and use the already resident Kitbug+ if I want 110 baud for the TELEKIT.

Photo of the adapter board in the LCDS, both patiently waiting for me to get to them. Was the RAM card you made based on the National Semiconductor ISP-8C/002N 2K RAM card? or a from scratch design?

[HelloWorld]

[QUOTE=Realtime;1731645]

Originally Posted by HelloWorld

I've searched high and low through my LCDS downloads and data snippets and haven't been able to find the source of that diagram (the annotations are my own). The only other concrete thing I know is that the part number is ISP-8C/806, which probably appeared in a Nat Semi advert or newsletter

Here is a May of '78 electronics design article with the emulation card number listed. it is one of the cheapest cards on the list, so i am not sure what all it could be emulating. The LCDS already offers single stepping, so if I had to guess, I suspect it is offering breakpoint and maybe some sort of offboard memory remapping?

[Realtime]

Originally Posted by HelloWorld

Here is a May of '78 electronics design article with the emulation card number listed. it is one of the cheapest cards on the list, so i am not sure what all it could be emulating. The LCDS already offers single stepping, so if I had to guess, I suspect it is offering breakpoint and maybe some sort of offboard memory remapping?

Thanks for the article. I had already seen that but couldn't track it down. As shown in the photo in #1 the Processor APC plugs into the emualtion card, so it must be acting as an arbiter between the LCDS and target hardware, with the LCDS debugger functions being made available to the target. It looks like there's a 40 way ribbon cable to connect to the target's procesor socket. Breakpoints are already offered on the LCDS through the HALT instruction, but perhaps the emulation card makes it a bit more elegant to set up.
As for cost, I would think it's relatively cheap because there is no RAM/PROM on the emulation board which would have bumped the price up.

[Realtime]

Originally Posted by HelloWorld

Was the RAM card you made based on the National Semiconductor ISP-8C/002N 2K RAM card? or a from scratch design?

My 64K RAM/ROM card is a home brew, re-purposing a SC/MP PCB I had previously designed. It has 32K SRAM, 64K EPROM and a small CPLD to slice the memory map. It's actually a very versatile module. I keep thinking about doing a proper PCB for it with a Eurocard connector at one end and PCB fingers at the other, so it can be plugged into both variants of the LCDS. Probably replace the CPLD with a GAL as well.


Here are 2 nice photos of the 2K RAM card (from eBay I believe). Interesting that this module has card extractors suggesting it was targetted at more than just the LCDS.

[HelloWorld]

Originally Posted by Realtime

My 64K RAM/ROM card is a home brew, re-purposing a SC/MP PCB I had previously designed. It has 32K SRAM, 64K EPROM and a small CPLD to slice the memory map. It's actually a very versatile module. I keep thinking about doing a proper PCB for it with a Eurocard connector at one end and PCB fingers at the other, so it can be plugged into both variants of the LCDS. Probably replace the CPLD with a GAL as well.
Attachment 322283

Here are 2 nice photos of the 2K RAM card (from eBay I believe). Interesting that this module has card extractors suggesting it was targetted at more than just the LCDS.
Attachment 322284 Attachment 322285

too bad i didn't know that i was going to be attracted to the LCDS back when this RAM card was on ebay. i wonder what it sold for and how it was described in the listing.

[HelloWorld]

Originally Posted by Realtime

Thanks for the article. I had already seen that but couldn't track it down. As shown in the photo in #1 the Processor APC plugs into the emualtion card, so it must be acting as an arbiter between the LCDS and target hardware, with the LCDS debugger functions being made available to the target. It looks like there's a 40 way ribbon cable to connect to the target's procesor socket. Breakpoints are already offered on the LCDS through the HALT instruction, but perhaps the emulation card makes it a bit more elegant to set up.
As for cost, I would think it's relatively cheap because there is no RAM/PROM on the emulation board which would have bumped the price up.

....as far as breakpoint, i was thinking of the ability to break at a specific address, opcode, or data byte without modifying the program and inserting a halt.

If I were designing this... the core feature would be to define one of these breakpoints (while in kitbug debug mode), and then run the user code until the specified match, and then exit to kitbug for register display/modification.

lots of dip switches on this little guy, I certainly hope they weren't using switches to define breakpoints. maybe the switches were to remap memory from the test platform back to the LCDS hardware.