4MB Romy Functional!

[SpeedGeek]

Originally Posted by grelbfarlk

Do any of the Kickstart to Fast RAM remappers know how to handle a 4MB ROM?

Romy does more than provide extended ROM. It also provides faster ROM access than Fat Gary. The CPU nodatacache Bustest results for my A3640 @ 40 MHz are as follows:

3.System3.9:> bustest addr e00000
BusSpeedTest 0.19 (mlelstv) Buffer: 262144 Bytes, Alignment: 32768
================================================== ======================
memtype addr op cycle calib bandwidth
user $00E00000 readw 152.0 ns normal 13.2 * 10^6 byte/s
user $00E00000 readl 152.2 ns normal 26.3 * 10^6 byte/s
user $00E00000 readm 159.1 ns normal 25.1 * 10^6 byte/s
user $00E00000 writew 151.7 ns normal 13.2 * 10^6 byte/s
user $00E00000 writel 152.6 ns normal 26.2 * 10^6 byte/s
user $00E00000 writem 152.3 ns normal 26.3 * 10^6 byte/s

3.System3.9:> bustest fast
BusSpeedTest 0.19 (mlelstv) Buffer: 262144 Bytes, Alignment: 32768 ================================================== ======================
memtype addr op cycle calib bandwidth
fast $07108000 readw 206.3 ns normal 9.7 * 10^6 byte/s
fast $07108000 readl 207.8 ns normal 19.2 * 10^6 byte/s
fast $07108000 readm 215.2 ns normal 18.6 * 10^6 byte/s
fast $07108000 writew 206.6 ns normal 9.7 * 10^6 byte/s
fast $07108000 writel 206.8 ns normal 19.3 * 10^6 byte/s
fast $07108000 writem 206.6 ns normal 19.4 * 10^6 byte/s

But even if the fast RAM is a little faster than the ROM, remapping with the MMU does not always improve perfomance because the MMU does add wait states. The fast RAM should have at least 1.5x the bandwith of the ROM to guarantee a faster remap.

[SpeedGeek]

UPDATE:

I just discovered that Doobrey's Make1MegROM tool can be used to make > 1MB ROMs!

I just built a 4MB ROM (see images below)! Now, one of these days I need to acquire some 42 pin programmable devices...

[kgc210]

Just got my 27C160 adaptor boards through that I designed. Hopefully they fit / work as first time I have ever designed anything in Eagle CAD.

I have also added the option to use a 322 in case you add support for it in the future.

[Peckmore]

Originally Posted by SpeedGeek

...and the new "Ramy" adapter by Cosmos is interesting:

http://leblogdecosmos.blogspot.com/2...y-arrivee.html

I've got a Romy adapter (not sure which version) which was purchased from Cosmos, and he seems to indicate on his blog that it is updatable to support 4MB Roms. Is the Ramy adapter also needed?

And once my Romy is updated (and potentially the Ramy adapter is in place) would I still be able to use 1MB roms if I wanted, or would I only be able to run 4MB roms?

Finally, massive thanks for everyone's hard work on getting 1MB+ Rom support on the A3000/A4000!

[SpeedGeek]

Originally Posted by Peckmore

I've got a Romy adapter (not sure which version) which was purchased from Cosmos, and he seems to indicate on his blog that it is updatable to support 4MB Roms. Is the Ramy adapter also needed?

And once my Romy is updated (and potentially the Ramy adapter is in place) would I still be able to use 1MB roms if I wanted, or would I only be able to run 4MB roms?

Finally, massive thanks for everyone's hard work on getting 1MB+ Rom support on the A3000/A4000!

As I previously mentioned you don't have to use the full 4MB of ROM space, you may use any fraction of the space you wish provided that your ROMs are built specifically for the new address space.

However, if you want keep your existing ROMs as spares then it probably makes more sense to purchase another GAL and program it with the 4MB Romy version. Then you can simply change the GAL when you want to change the ROM size.

The Ramy adapter is not required (see the first Cosmos blog link) but is just an option if you want to make your hack real "Fancy" (if I remember my British vernacular correctly).

BTW, Cosmos has only confirmed the 4MB Romy functional with an A4000D. Unfortunately, the A4000T NCR SCSI design kludge bug continues to strike out from the grave. I also understand it's causing real havoc with the "Chucky" A3640 PCB clones!

[gulliver]

With 4MB of rom space, in theory you could have both an updated kickstart and the entire AmigaOS 3.1 system. Sounds interesting.

[Peckmore]

Originally Posted by SpeedGeek

As I previously mentioned you don't have to use the full 4MB of ROM space, you may use any fraction of the space you wish provided that your ROMs are built specifically for the new address space.

However, if you want keep your existing ROMs as spares then it probably makes more sense to purchase another GAL and program it with the 4MB Romy version. Then you can simply change the GAL when you want change the ROM size.

The Ramy adapter is not required (see the first Cosmos blog link) but is just an option if you want to make your hack real "Fancy" (if I remember my British vernacular correctly).

BTW, Cosmos has only confirmed the 4MB Romy functional with an A4000D. Unfortunately, the A4000T NCR SCSI design kludge bug continues to strike out from the grave. I also understand it's causing real havoc with the "Chucky" A3640 PCB clones!

With regards to ROM size that makes sense then - so I have to use 4MB Roms (as in EPROM/EEPROM) but don't have to use the full capacity of those Roms. At least now I can order the right thing if/as/when I get a Ramy adapter.

Speaking of the adapter, it is indeed "fancy"! I'll be honest, my preference for mods is to make them as reversible as possible, so the Ramy adapter appeals to me more than soldering wires to chip legs (that and my soldering is not the best!)

And I've currently got a 4000D so hopefully I should be all good compatibility wise!

Many thanks for clearing this up for me.

[nogginthenog]

Originally Posted by gulliver

With 4MB of rom space, in theory you could have both an updated kickstart and the entire AmigaOS 3.1 system. Sounds interesting.

ROMDISK by Christian Vogelgsang should allow that.
https://github.com/cnvogelg/romdisk

[SpeedGeek]

Originally Posted by Peckmore

With regards to ROM size that makes sense then - so I have to use 4MB Roms (as in EPROM/EEPROM) but don't have to use the full capacity of those Roms. At least now I can order the right thing if/as/when I get a Ramy adapter.

Speaking of the adapter, it is indeed "fancy"! I'll be honest, my preference for mods is to make them as reversible as possible, so the Ramy adapter appeals to me more than soldering wires to chip legs (that and my soldering is not the best!)

And I've currently got a 4000D so hopefully I should be all good compatibility wise!

Many thanks for clearing this up for me.

Well, again as I previously indicated you don't need to use 4MB devices either unless you intend to build 4MB ROMs.

Apparently, my British vernacular was a little rusty. The adapter is not required but optional if you "Fancy" a splendid hack!

...and hopefully the next time I will get it right "Straight Away".

Originally Posted by nogginthenog

ROMDISK by Christian Vogelgsang should allow that.
https://github.com/cnvogelg/romdisk

Unfortunately, despise all the enthusiasm it still only supports 1MB.