Model 100 RAM: Difference between revisions

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==Francesco Messineo module==
=Original=
https://drive.google.com/folderview?id=1rF_nFrhEnfzX1KegC4IFeMjA82ylhO0f
The original ram came in the form of 4 2Kx8 on a ceramic carrier module to make a single 8k chip, and up to 4 modules total may be installed for a total of 32k.


==NEC module==
Each module still acted like 4 seperate 2k chips. The 2k chips are combined physically but not logically. There are 4 seperate chip-select lines for each module socket, and when ram is accessed, only one of the individual 2k chips is selected by it's own dedicated chip-select line.
There was an NEC module on ebay for a while. These work in Model 100.


http://ebay.com/itm/251666092812  (sold out now)
{|
|-
| Radio Shack 26-3816 || [[File:Radio Shack 26-3816 8k ram module.jpg|thumb]]
|-
|}


<!-- dead link
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-->
Pics https://goo.gl/photos/gGVSWwGiv9NSwveR7


=Replacement=


If someone wants to clone the design, I have a few of these and can send you one.
==Buy==
Some new modules you may be able to buy. (stock comes and goes, people making and offering something come and go)


8k (8,192-word) × 8-bit Static RAM
[https://www.arcadeshopper.com/wp/?page_id=11#!/8k-RAM-module-for-Model-100/p/104430801/category=28313042 Francesco Messineo]<br>
[https://www.ebay.com/itm/402652485830 GGLABS M10MEM]<br>


Components:<br>
==Build==
NEC D4364G-15L<br>
You can always build your own.
<!--  dead link
http://www.electronicbeetle.eu/beetle/ICS/memory/RAM%20SRAM/SRAM%2008kx8%20Module%20D4364G-15L.pdf
-->
TIHC148 (Texas Instruments' 74HC148)


Length 36mm / 1.42"<br>
This is a new design using all parts you can still buy new today.<br>
Width 22mm / 0.87"<br>
https://github.com/bkw777/Model_T_RAM
row spacing 19mm / 0.74"<br>
{|
pin pitch 2.54mm / 0.1"
|-
| bkw777 Model_T_RAM || [[File:bkw777_model_t_ram.jpg|thumb]]
|-
|}
 
Here are some other designs<br>
[https://drive.google.com/open?id=1U_T8bdf7bJZ8vM9IxSQHVU1slsC0df1o Francesco Messineo]<br>
[https://oshpark.com/shared_projects/wn2DEsJc Stardust SMT]<br>
[https://oshpark.com/shared_projects/8ZE4c4ue Stardust DIP]<br>
[https://gglabs.us/node/2100 GGLABS M10MEM]<br>
 
==Test==
Hardware tester using arduino https://youtu.be/5fFRrfUjogs
 
BASIC software tester https://archive.org/download/M100SIG/M100SIG.zip/Lib-07-UTILITIES%2FRAMTST
 
==Past 3rd party==
There have been many 3rd party ram modules over the years. Here are just a few examples.
 
{|
|-
| NEC PWD-458 || [[File:NEC_PWD-458.jpg|thumb]]
|-
| Purple Computing 1983|| [[File:Purple Computing RAM Module.jpg|thumb]]
|-
| Purple Computing 1985|| [[File:Purple Computing 1985 RAM Module.jpg|thumb]]
|-
| C.I. 1984 (possibly Cryptronics?) || [[File:C.I. 1984 RAM Module.jpg|thumb]]
|-
|}
 
==Other==
There are also ram expansion accessories that connect to the system bus and either add extra banks of 32k to the internal ram, or replace the internal ram. These aren't normal ram modules that plug into the normal ram sockets. They plug in to the system bus connector and provide the entire 32K address space at once from there, as if all ram sockets were filled.
:[[QUAD]]
:[https://www.github.com/bkw777/reQUAD reQUAD]
:[[PGDesigns]]
:[[PCSG]]
:[https://bitchin100.com/wiki/index.php?title=REXCPM REXCPM]

Latest revision as of 04:52, 17 October 2023

Original

The original ram came in the form of 4 2Kx8 on a ceramic carrier module to make a single 8k chip, and up to 4 modules total may be installed for a total of 32k.

Each module still acted like 4 seperate 2k chips. The 2k chips are combined physically but not logically. There are 4 seperate chip-select lines for each module socket, and when ram is accessed, only one of the individual 2k chips is selected by it's own dedicated chip-select line.

Radio Shack 26-3816


Replacement

Buy

Some new modules you may be able to buy. (stock comes and goes, people making and offering something come and go)

Francesco Messineo
GGLABS M10MEM

Build

You can always build your own.

This is a new design using all parts you can still buy new today.
https://github.com/bkw777/Model_T_RAM

bkw777 Model_T_RAM

Here are some other designs
Francesco Messineo
Stardust SMT
Stardust DIP
GGLABS M10MEM

Test

Hardware tester using arduino https://youtu.be/5fFRrfUjogs

BASIC software tester https://archive.org/download/M100SIG/M100SIG.zip/Lib-07-UTILITIES%2FRAMTST

Past 3rd party

There have been many 3rd party ram modules over the years. Here are just a few examples.

NEC PWD-458
Purple Computing 1983
Purple Computing 1985
C.I. 1984 (possibly Cryptronics?)

Other

There are also ram expansion accessories that connect to the system bus and either add extra banks of 32k to the internal ram, or replace the internal ram. These aren't normal ram modules that plug into the normal ram sockets. They plug in to the system bus connector and provide the entire 32K address space at once from there, as if all ram sockets were filled.

QUAD
reQUAD
PGDesigns
PCSG
REXCPM