Amstrad Diagnostics ROM

[Prodatron]

I am used to...
- primary 64K ram bank
- secondary 64K ram banks (multiple)
Now Noel has a lot of choices

[GUNHED]

How about "Core RAM"? Without the core, nothing will work.

Four letters... already the right size of a word. 

/unserious mode on
However, I brings me to the idea to see if a CPC can work without RAM. Once I had the 6128plus running without firmware+basic. Time to make a rom-only os then... 
/unserious mode off

[eto]

Time to make a rom-only os then... 

Fun fact: The amstrad diagnostics is ROM only- at least partially. The lower RAM check works without any RAM being attached. 

[f-bone]

hi guys! what a great piece of work!.. need to ask a question regarding the M4 board.. I managed to get it to work by adding the upper diagrom in the root of the SD card and then run |diag.

the question is can I somehow set it up that when I power on the CPC6128 the diagrom is booted automatically from M4 so I can troubleshoot machines with corrupt ROM chips or bad ram?

thank you so much!

[pelrun]

Put the lowerrom version in a high M4 slot and configure the M4 to use that slot as lowerrom. That will boot it on startup.

[f-bone]

perfect thank you pelrun! I will try that tonigh/tomorrow (need to read first how I set M4 to use it as lowerrom)

[WacKEDmaN]

At the meaning of words, Lower RAM and Upper RAM do not exist.

That is correct. Is there a better term to describe the difference between the default 64KB RAM and the RAM can can be swapped into place? Happy to use it as long as it fits in there :-)

For the first 64 KB: Main RAM
For the next 512 KB (via &7Fxx): Expansion RAM
For the next 3,5 MB (via. &78, &79, &7A, &7B, &7C, &7D and &7E): Extension RAM
That's also used by FutureSoft manuals. It describes pretty good I think.

(Annotation: imo the first 64 KB shouldn't be called base ram, since ram byte &FFFF really is not at any base).

looking at these images on grimware site..it would make sense to call it "base ram" and "extended ram"

[ikonsgr]

Finally,i manage to run diagnostic using my new ULIfAC board (e.g. merge of USIfAC II+ RAM/ROM board):

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What fixed the crashing problem (in ROM test, when it reached usifac's rom number) was to incorporate diagnostic tool into an RSX command (using the binary from dsk image).
 I also tested using upper and lower diagnostic rom too, but with upper rom, it crashed in rom test, and using the lower rom (boots directly into diagnostic tool), it seems to reboot rom (runs again basic 64k ram test and gives initial screen).
 Anyway,i think it would be helpful to have this great dignostic tool as an rsx command for direct usage ;-)

[pollito]

Just a clarification of what @pelrun said regarding running the diagnostics using an M4 card (I've just done this).

Assuming the OS ROM is in slot 31, upload the Diag Lower ROM to slot 30 (low is high! ). Then, scroll up to the top and make sure Lower-rom Enabled is ticked, and Set. Then, change Lower-rom slot to 30, Set it, and do an M4 Reset from the Control page.

Note that once the CPC crashed when I configured the above, after the M4 reset. If this happens, power cycle the CPC, and the diagnostics should run as normal.