CFX-II first pictures

[Martin A]

Meet the CFX-II
it Features:
80 column colour/mono/enhanced colour VGA output for CPM
Optional 512k Silicon Disc
optional 32k Ram for MTX500 to run CPM
Up to 8 8mg partitions on the CF for CPM (4 from basic using SDX extensions)
CPM boot rom
SDX Basic extension rom

The CF interface is now 8bit transfers only, so no hard drives - Sorry - but the raw speed improvement was worth it! The low level transfer rate is twice as fast as the original CFX.

The video circuit is Bill's propeller based display that he demonstrated at Memofest, coupled with his latest software which allows both a FDX style 8 colour display and an enhanced 64 colour version. There's a programming header on the board to allow for updates.

The 512k silicon disc is a single 32pin static ram, unlike the original MTX dynamic ram based boards which needed multiple memory devices. Despite the construction differences, it's fully compatible with the original Memotech type 41 drive, as shown in the central picture, and uses the original driver.

The CPLD provides all the glue as well as the level shifting to allow the MTX CPU to read back data from the propeller. That removed the need for the GAL and 74HCTxxx parts on the Prototype. The in-system programming header for that is also on the board.

Not included on the prototype, but present on final board is a 32k "skinny DIP" ram chip that Dave's somehow managed to squeeze onto the board, that could be used to upgrade the MTX500 to 64k. On the MTX512 it's not needed and would be left off.

The CPM and SDX roms are again based on the MTX sources from Andy's site to maintain as much compatibility with the originals as possible, the latest CFX enhancements such as USER DRIVE are included.

The new board connected to the MTX

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Output from the VGA port

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The prototype nearing completion

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[1024MAK]

Darn, I still can't find that like button

Great work and thanks to all who helped in the development of this

Mark

[lezanderson]

Another cool gizmo for the MTX ...

It's amazing what you boys get up to with a Soldering iron and a few components !

[protek]

Awesome new project! Thanks for sharing!

[Potholepete]

Really impressive bit of kit both hardware and software wise

[Crazyboss]

cool

Is is a Rememorizer RIPoff ? prepare yourself for a lawsuit

[Dave]

You mean in the same way that REMEMOrizer ripped off SDX & FDX ?

[Martin A]

I've just sent Dave the latest version of the Boot rom, the SiDisc code's been re-written and is included in the rom.

Booting off the SiDisc is now supported if the drive has previously been set up.

The drive's low level code has also had a work over. The original Memotech SiDisc driver would verify after every read and write, which slowed things down a lot, I've taken that out. Modern SRAM doesn't have any reliability issues that would require a verify.

There are other improvements which means the current raw transfer rate is 230k/sec. Just short of the theoretical maximum of 250k/sec which would need quite a bit more space within the rom.

The reason for all this ?

Dave is currently trialling a 512k NVRAM on his board. With the battery backup, the SiDisc becomes permanent storage. You get a 4mhz Z80 based system that has a boot drive as fast as the hard drive in the first PC I had (and that was a 10mhz 286 based Apricot).

Hopefully Dave will post some pictures of the board....
(that's a hint!)

[Dave]

OK, OK - hint taken

You can see the 512kb NVRAM (Courtesy of Lez) at the bottom of the photo.
It is a drop-in replacement for the 512k SRAM and includes an internal backup battery

[Crazyboss]

Cool, could someone make a compare sheet between the CFX and the Rememorizer ?