Whats he deal with the Rom Tower?

[alexh]

Cldrnbrn wrote:
1. what is the rom tower really used for?

Amiga ROMS have a fairly unusual pinout. At the time EPROMS with the same pinout as regular Amiga ROMS (e.g 27C400) were very expensive.

When developing KS2.0 there were many updates of KS ROM and to make things cheaper, early developer A3000's have ROM sockets which take standard pinout EPROMS.

A ROM tower converts regular pinout Amiga ROMS for use with these sockets.

Cldrnbrn wrote:
2. do I actually need it?

It depends. Later (Rev9) A3000's have normal ROM sockets and so A3000 ROMS came in two flavours. If you have one of these early (Rev7) A3000's and you have "regular" A3000 ROMS then you need a ROM tower to convert.

Cldrnbrn wrote:
3. why are there 4 rom slots on a motherboard but only 2 used for the rom tower?  what are the other 2 for?

I think they are for extended ROMS i.e. ones larger than 512kbyte, but dont quote me on that.

4. If I use the tower what is the correct orientation?

Unsure, but it will be obvious given the "notches" in the sockets and in the rom tower.

5. I have a set of 3.1 roms I'm trying to install, so would I need the tower for that or can I plug directly into motherboard?

Really depends on which type of ROMS they are and which A3000 you have. If you have anything other than a Rev7 motherboard, chances are you need a ROM tower.

There is a picture of a ROM TOWER and the "special" ROMS on the A3000 page on BBoAH (http://www.amiga-hardware.com)

The problem with using a ROM tower is that an AmiFast ZiptoSIMM converter wont fit. If you have fully populated ZIPRAM (16Mbyte) then it is not a problem.

[alexh]

Borkmaster wrote:
My understanding is that early revision A3000 motherboards used ROM sockets that were wired for EEPROM chips, not permanent mask ROM chips normally as used in other models.

That's what I just said, but they were for cheap EPROM's in general. Not necessarily EEPROMS. It was all down to the pricing of the 27C400 chips I feel (EPROMS with Amiga MASK ROM pinout).

Commodore split the ROMs into two chips (high order and low order).  Not many EEPROM programmers can handle this.

I dont think this is true. All EPROM programmers that I have ever used, the software has supported 32-bit data, 16-bit EPROMS (i.e. splitting data). And I've used a LOT.