Capture

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Capture Screenshots
Capture Screenshots
Technical Info
ROM 8 kbyte
RAM 8 kbyte
Hardware features 1 Button Freeze
Manual PDF: 11 pages - includes all necessary info
PNG: 1 page - v1.1 Upgrade Note
CRT ID 34
Programming
Control Registers $FFF7 - any RW access disables Cart at $E000 and leaves Ultimax
  $FFF8 - any RW access enables Cart at $E000 and enters Ultimax
  $6000 - $7FFF has the Cart RAM accessible when Ultimax is enabled
  The registers are enabled by the cartridge button and are disabled on reset only

Capture was introduced to the american market in August 1985 (Capture September 1985 Advert) with an update to Capture II between mid 1987 and December 1987. Capture was produced by the Jason-Ranheim Company and widely distributed as Capture Archival Cartridge System due to its extra support for creating ready to eprom program output for the promenade C1 eprom burner. The hardware base for the cartridge never changed while the 1.0 software was upgradable to 1.1 (supposedly around mid 1986) and 2.0 (or II) by replacing the eprom (offered by the Jason-Ranheim Company as well).

Capture came with 8kb of ROM as well as 8kb of RAM and was second on the market of commercial freezing cartridges. Its software is simple but well done and due to its limited space uses up the eprom pretty well. What people will usually regard as lack of features makes Capture somewhat special since it should be extremely hard to detect by normal software. The main menu option LOAD-EXECUTE was at some time obviously intended to introduce additional software running off the cartridge RAM to the Capture platform but so far such software was not found.

Capture Cartridge from top

A comparison of the Capture II versus 1.1 ROMs has yielded that little was changed between these two releases. The freeze routine was improved by handling a timer differently and the cartridge menu being burned to eprom on the promenade got a few new bytes. Overall less than about $80 bytes got added from 1.1 to II and no obvious changes apart from a little text was done.

Memory dumps created by Capture are really what the name says - memory dumps with information on registers and program counter added. The description of the resulting file contents is well documented on the manual and easily allows later modification on the frozen program. Apart from this Capture does nothing else but filling the memory and dumping it in restartable form to disk, tape or "cartridge".

Along with a multiple of 2-kbyte files containing the memory dump there are files created containing the IO state of the C64 and there is an option to store the drive RAM as well. It should be noted that the drive RAM is not restored on reloading the frozen program though. Additionally disks containing captured programs are not easily file copyable since the cartridge is installing a few fast loader bits to track 18 sectors 15 and 18. You will need to copy these as well.

This cartridge is a true NMI-Freezer. On button press the NMI is triggered and through the NMI vector pointing to somewhere at the $FEXX page the computer ends up at $EAEA. Here the actual freezing takes place by storing registers to the cartridge RAM available during Ultimax-Mode at $6000-$7FFF.

Jason-Ranheim Company sold a variety of eprom related products for the VIC-20 already and produced the promenade C1 eprommer for the C64 before the Capture cartridge apparently. Capture was mainly advertised as a companion to the promenade C1 though it should be seen as stand alone product with an extra option to round the company portfolio. It should also be mentioned that the promenade C1 was cloned by several people and seen by many as the eprommer standard in the USA.

Capture II Advert 12/1987
Capture II Advert
Run Issue 48, 12/1987

"Load and Execute" Plugins

"Load and Execute" plugins are loaded to $0800. Then the first 3 bytes are checked for a "JRC" signature, and $0800 to $08FF is XORed with $FE00-$FEFF before the plugin is started by a JMP ($0804).

A simple plugin therefor can be created like this:

    *=$0800
    !byte $4a, $52, $43  ;"JRC"
    !byte 0
    !byte $00 XOR $4c, $09 XOR $ea ; fe04  4c ea
 ;--------------------------------------------------
    *=$0900
    ; plugin code here
    lda #$1b  ; enable display
    sta $d011
    inc $d020 ; do something :)
    jmp *-3

As the memory gets trashed anyhow the length of the plugin does not matter much.

Notes

  • Ahoy! Magazine Issue 27 (March 1986) mentions a missing PROM programming feature and incompatibilities to early C128 models. It also states that the v1.1 upgrade was about to resolve these issues. The article reviews ISEPIC and Snapshot 64 next to Capture and concludes that all freezers are at about the same level and efficiency.
  • Ahoy! Magazine Issue 47 (November 1987) is revisiting the Capture cartridge and states the availability of a ROM update resolving the C128 incompatibilities and adding the PROM programming option. We can only assume which version they tested since the differences on Capture v1.1 and Capture II are not too obvious and no photos were provided.

Missing

  • Capture Schematics
  • ROM dump of Capture 1.0
  • Affiliate programs if there were any. The "load-execute" option promises plugins of some kind.

Binaries

Capture_binaries_rr.c64.org_2010-03.rar contains just the C64 binaries:

  • Capture 1.1 decoded .bin and converted .crt
  • Capture II decoded .bin and converted .crt


Capture_all_rr.c64.org_2010-03.rar contains:

  • all of the above
  • Capture Manual Scan (two PDF files)
  • Capture V1.1 Upgrade Note (one PDF file)
  • Capture Cartridge Hi-Res photos
  • Decoding material including the c source for the decoder and PDF files to the chips used with this hardware

Trivia

 Acknowledgements

 We would like to thank the following people for helping to make Warp Speed a reality:

 Dave Morelli
 Fred Wasserman
 Bob and Phyllis Jacob
 Eric Roberts
 Jason Ranheim Company
 and all the people who wrote in to comment on version 1.0! We hope you like this new version

The Warp Speed ROM dump is similarly crippled and needed decoding just like the Capture ROM dump - OK, no big deal since there are other examples of changing data lines as well but the relation is interesting trivia. :)

  • The Jason-Ranheim PCC-8 eprom board system is mentioned on U.S.patent 4,785,420.
  • "The Jason-Ranheim company no longer sells or supports Commodore products. As such, they saw no harm in allowing their copyrighted materials be used in this way by people who still have access to the PROMENADE." quoted from Promenade Manual at zimmers.net - we hope they think the same way about Capture. Emails were not answered (yet).
  • "Jason-Ranheim (still in business making PC based products) clearly indicated about a decade ago that they couldn't care less about what people do to or with their vintage Commodore related hardware and software." and "JR will not answer in any way to anyone asking anything about Commodore related equipment... " quoted from the Lemon64 forums.

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