In this section I'll try to explain what are the changes to be done on various cards to use different computer configurations.

Due to the high number of cards, it's very difficult to show what are all possible configurations, because they can be combined in almost every manner. But there are some limits, mainly for the used address space and firmware versions and operative systems that support the various cards, so it's not always possible to make all combinations if you don't build the multi-boot firmware as explained in the add-ons section.

All firmwares and operative systems shown in this page are available in the software section.

The following table shows the address space used by various cards, both for memory and input/output addresses. Using this table it should be easier to understand what cards are compatible themselves and what aren't.

Additionally, various cards need various eproms with the proper firmware to manage them. Depending on the plugged eprom it's necessary to make different changes to the CPU card or to the floppy interface card so that the choosen eprom can take control of the computer at reset. It's even possible to mount more eproms (one eprom for card on different cards) but the user has to do more operations to use the eprom that is not on the CPU card. Infact in this case it's necessary to set the eprom address using the hexadecimal keyboard and manually start the program execution. In any case this is not suggested because it makes impossible to use NE-DOS version 1.5 and more, because the addresses occupied by eprom "382" must be available to ram (NE-DOS version 1.5 requires at least 40 KBytes of ram).

The only exception is the eprom programmer firmware, that must be necessarily installed together with eprom "382" that is mounted on the CPU card.
In the add-ons section there are explanations about how to build a card with a multi-firmware boot to use all cards together.

In the following table thare are the requirements for every operative system, in terms of ram, firmware, and needed cards (beyond to the bus card and the power supply).

In the following table there are the changes to be done to support every kind or card.

Note that to use NE-DOS or SONE that require at least 40 KBytes of memory (both with the video interface LX.388 and LX.529) it's always necessary to disable the eprom on the CPU card and to change the reset circuit, with the result to loose the possibility to use the hexadecimal keyboard monitor.

Anyway to use any operative system (also the hexadecimal keyboard) it's possible to build the multi-boot firmware card as explained in the add-ons section, as an alternative to the following changes.

As a start for these changes it's assumed that on the bus card there is only the CPU card with 1K ram on board and eprom "382".

NOTE: in addition to what indicated in the article COME ESPANDERE LA MEMORIA NEL COMPUTER on magazine number 77, if you want to use the eprom on LX.382 cpu card together with only one or two LX.392 dynamic ram cards (without using any LX.386 static ram cards) you must do the following patches on the LX.382 cpu card:

• Remove two 2114 ram
• Raise pin 13 of IC8/A (74LS00)
• Connect raised pin of IC8/A directly to pin 10 of IC9/B (74LS04).

Additionally, in case you want to disable the eprom on the LX.390 floppy-disk interface, you need to make the following paches on LX.390 card:

• remove IC2 chip (it's the 74LS30 at low left on the board)
• connect pin 1 of IC3 to pin2 of IC3 (the same chip - it's the 74LS08 at high left on the board)
• remove eprom IC6 (it could also be left in place)
• remove jumper P1

By correlating data in previous tables it should be possible to understand what changes to do to use any kind of operative system.

In any case if you have any doubts or questions don't hexitate to e-mail me.