Vortex Expansions RAM card

RAM expansions card from Vortex.

Not compatible to the dk'tronics memory expansion.

Sold in different sizes of RAM as SP 64, SP 128, SP 256, SP 320 and SP 512.

Resulting in a maximum RAM size of 576K (64K internal, plus 512K external).

Usable under BASIC and CP/M and offering a RAM disc.

Pictures

• The Vortex Expansion RAM card
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  Vortex Expansion RAM (top)

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  Vortex Expansion RAM (bottom)

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  CPC 464 before put the Expansion RAM card

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  CPC 464 after put the Expansion RAM card

Technical (very incomplete)

• This section describes how you can access the RAM of the SP512.
• The exact decoding (e.g. complete or partial) of I/O port addresses is not confirmed at this time.
• The port addresses given are recommended and are those used by B.O.S..

I/O port &FBBD:
Bit	Function
7	Unknown
6	Unknown (Discology utility uses it - does it choose RAM in 32K blocks instead of 64K blocks??)
5	When 1, bits 2..0 define which 64k block of SP512 RAM to select. When 0, chooses internal 64K RAM of CPC464.
4	Unknown
3	Unknown
2..0	Used to choose the 64K block of the SP512 to select

I/O port &7F00:
Bit	Function
7	Set to 1
6	1 = make RAM visible in range &8000-&FFFF, 0 = make RAM visible in range &0000-&7FFF
5	Set to 1 to activate SP512. If bit 5 of &FBBD is 1 will select SP512 ram, otherwise select RAM of CPC464.
3	1 = Upper ROM disable, 0 = Upper ROM enable
2	1 = Lower ROM disable, 0 = lower ROM enable
1,0	Screen mode

• When bit 5 is 0, then bit 6 is ignored.
• When reading, ROM has priority over the RAM.

Manual

Vortex SP 512 kb RAM Expasion Manual (pdf) (german)

Software

• BOS (Vortex Banked Operating System) (RSX commands on built-in EPROM, mapped to ROM bank 6) (under BASIC, the RAM is used as program/data region, BASIC programs can |GOTO and |GOSUB to expansion banks)
• Driver Cassette (includes PATCH.COM for upgrading CP/M to support the expansion RAM) (62K TPA, plus RAMDISK and printer SPOOLer)
• Discology
• RCPM (RAM CP/M)

Weblinks

Vortex/ICP-Homepage

Vortex SP512 RAM Card