Author Topic: Nova - NVRAM + RTC for Amstrad CPC - Latest news from PulkoTronics  (Read 2504 times)

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Offline zhulien

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I think I get it now, you want to read the config file from the ROM before the system comes back to the user, but that can still be done depending on the order of the ROMS if you want to fall back on other existing FS ROMS during the boot process.  This does limit the system startup though in ways which are best resolved via NVRAM.


The other option as I suggested was just to let the system boot to BASIC, once in BASIC whatever existing ROMS are in place can be used to configure UniDOS before UniDOS takes over.  This can be done via RSXs but still the same limitation as no NVRAM.


Then a custom-patched ROM with small BASIC ROM patcher would ultimately be the next best option without NVRAM.

Offline zhulien

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As Sykobee suggested, i was thinking if you treat your NVRAM as slots like you said, but had the first slot being used by the NVRAM itself for a RAT (RAM Allocation Table).  Examples of how I am setting up a RAT for banking is here:



https://docs.google.com/spreadsheets/d/1XgRVlh27K_C0-gMtroMhN8lK9mAQxVQg1x-3M42kBYo/edit#gid=1980957477


and is fast for allocations and deallocations.  Just as per the examples here setup a RAT for each NVRAM if you have multiple and the same pattern should work well.


As you can see, one or more entires in the RAT can be allocated by a single driver (or application in your case).  D (allocated by driver), E (extension of the allocation), F (free), A (application)... DEEF means a driver allocated 3 blocks, the first free one is block 4.  When freeing the driver, the D and any subsequent E's need freeing.

« Last Edit: 15:01, 22 March 21 by zhulien »

Offline PulkoMandy

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Hi!


The Nova is fully working and available for sale now.


The board costs 35€ (a bit more than usual, because these NVRAM and batteries are not cheap).


Please contact me if you need one.

Offline zhulien

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could a AT24C256 work as NVRAM for this purpose when plugged into one of the many serial interfaces?  Usifac?  Lambdaspeak?


https://ww1.microchip.com/downloads/en/DeviceDoc/doc0670.pdf


https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=AT24C256&_sacat=0


Offline GUNHED

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Could a AT24C256 work as NVRAM for this purpose when plugged into one of the many serial interfaces?  Usifac?  Lambdaspeak?
https://ww1.microchip.com/downloads/en/DeviceDoc/doc0670.pdf
m570.l1313&_nkw=AT24C256&_sacat=0
m570.l1313&_nkw=AT24C256&_sacat=0
At least the LambdaSpeak III has an 128 KB EEPROM, which can of course be used as kind of nvRAM too. In this case the 128 KB are read / written through the LS I/O port. It's not banked in, but I/O is quick enough.  :)
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Offline Targhan

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@PulkoMandy So finally, how the UniDos will know at what address to look at to get its data?
And where a possible ùSNA would know where to store its own (it only needs temp data)?

Have you decided of anything to allow programs to reserve slots?
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Offline zhulien

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@PulkoMandy So finally, how the UniDos will know at what address to look at to get its data?
And where a possible ùSNA would know where to store its own (it only needs temp data)?

Have you decided of anything to allow programs to reserve slots?


Perhaps a few methods could be tried in sequence to see if the NVRAM (whichever method) is available?  Nova?  Lambdaspeak?  Serial EEPROM via Usifac?  Serial EEPROM via other serial ports?  I did suggest someone create an 8 serial port board in another thread - which something like this Serial EEPROM would be ideal for, perhaps an Usifac-8 (8 port).  Or an Usifac-4 (4 port)? @GUNHED

Offline PulkoMandy

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@PulkoMandy So finally, how the UniDos will know at what address to look at to get its data?
And where a possible ùSNA would know where to store its own (it only needs temp data)?

Have you decided of anything to allow programs to reserve slots?


I do only the hardware here. Contact OffseT if you want to know his plans for UniDOS.
There is 32K of space, I hope you can find an agreement on how to share it, there should be enough space for everyone!

Offline GUNHED

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There is 32K of space, I hope you can find an agreement on how to share it, there should be enough space for everyone!
Therefore we got this here:
https://www.cpcwiki.eu/forum/technical-support/application-user-ids-for-non-volatile-ram-(nvram)-listed-here-request-here/msg198965/#msg198965

Or do it in which way you want, but we should all have an agreement. Else software is incompatible again.
http://futureos.de --> Get the revolutionary FutureOS (Recent update: 2021.01.24)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.05.02)