Vortex Expansions RAM card

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Description

RAM expansions card from Vortex, mounted between CPC464 mainboard and CPU/Gate Array. It won't fit on CPC664, CPC6128, or CPC+ boards. The card is not compatible with the standard dk'tronics-sytle Standard Memory Expansions.

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). The smaller SP64-SP320 versions can be upgraded to SP512 by mounting additional RAM chips in the spare sockets.

Usable under BASIC and CP/M:

BASIC

BOS (Banked Operating System) RSX drivers are included on EPROM (mapped to ROM bank 6). Providing following features under BASIC:

  • Banked BASIC programs (using |GOTO, |GOSUB, |RETURN commands, for example: |GOTO,bank,line)
  • Pseudo Floppy (unlike a RAMDISK, this "floppy" can be accessed only via special RSX commands)
  • Debugger (aka Z80 Monitor) activated via |MON (v1.0) or |XM (v2.1)
  • Printer Spooler
  • Plus some extras like |FAST and |SLOW

Note: Some of the RSX commands are always available, some only after typing |BOS.

CP/M

PATCH.COM is included on cassette. After copying the file from cassette to disk, it can be used to upgrade normal CP/M to support the expansion RAM. Providing following CP/M features:

  • 62K TPA
  • RAMDISK (unlike the BASIC Pseudo Floppy, this acts like a regular disk drive)
  • Printer Spooler

Note: There is a bug/problem with COPY.COM no longer working after installing PATCH.COM. A bugfix is listed in the appendix of the manual.

Pictures

  • The Vortex Expansion RAM card

  • Vortex Expansion RAM (top)

  • Vortex Expansion RAM (bottom)

  • CPC 464 before put the Expansion RAM card

  • CPC 464 after put the Expansion RAM card

Installation

See Installing Vortex Expansion RAM.

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

Note: Above is the original manual for BOS 1.0, not containing info on newer version(s) like BOS 2.1.

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)
  • Further patches - the manual contains additional patches for some BASIC and CP/M programs
  • Discology
  • RCPM (RAM CP/M, 1989-1990 by Günter Radestock) (RCPM is an alternative to the PATCH.COM from Vortex)
  • G-Paint 2.0 (by Günter Radestock)

Downloads

Weblinks

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