Category:REU RAM Expansion Units: Difference between revisions

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''RAM Expansion Unit'' also known as '''REU''' was produced and sold by Commodore. This rather popular device is well covered on the net currently and also emulated in software and hardware (e.g. by the [[1541 Ultimate]]) pretty well. The large Commodore version was followed by a CLD version and the CMD clones which all used a CSG8726 as controller chip. The ''REU'' is capable of initiating DMA transfers on request allowing storing, fetching and swapping memory with the C64 main memory. The C64 is not able to natively access the ''REU'' additional memory and programs need to utilise it especially.
''RAM Expansion Unit'' also known as '''REU''' was produced and sold by Commodore. This rather popular device is well covered on the net currently and also emulated in software and hardware (e.g. by the [[1541 Ultimate]]) pretty well. The large Commodore version was followed by a CLD version and the CMD clones which all used a CSG8726 as controller chip also called ''REC''. There are apparently two mounting case forms of the ''REC''. The square one is said to be more common here.


So far 128, 256, 512, 2048 and 16384 kb (yes, that's 16MB using a ''1541u'') were spotted at the expansion port.
The ''REU'' is capable of initiating DMA transfers on request allowing storing, fetching and swapping memory with the C64 main memory. While the C64 is not able to natively access the ''REU'' additional memory and programs need to utilise it especially the ''REU'' DMA is able to transfer memory extremely quick making it even a valid device for in main C64 memory moving.
 
So far 128, 256, 512, 1024, 2048 and 16384 kb (yes, that's 16MB using a ''1541u'') were spotted at the expansion port.


The ''REU'' is using up all of the IO-2 area from $DF00 - $DF0F and is mirroring that register range each $20 bytes. Cartridges operating at $DF00 will collide with the ''REU''. Known to work in parallel using a [[port expander]] are [[Retro Replay]] when using a ROM supporting the REU memory config and [[Super Snapshot]] while [[Expert Cartridge]] and [[:Category:Kernal ROM|Kernel ROM]] replacements (incl. [[ExOS]] and [[StarDOS]] cartridges) should work as well.
The ''REU'' is using up all of the IO-2 area from $DF00 - $DF0F and is mirroring that register range each $20 bytes. Cartridges operating at $DF00 will collide with the ''REU''. Known to work in parallel using a [[port expander]] are [[Retro Replay]] when using a ROM supporting the REU memory config and [[Super Snapshot]] while [[Expert Cartridge]] and [[:Category:Kernal ROM|Kernel ROM]] replacements (incl. [[ExOS]] and [[StarDOS]] cartridges) should work as well.
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==Emulation==
==Emulation==


Unfortunately emulation on several emulators yields problems in combination with common cartridges and other I/O devices. Results may vary here.
Unfortunately emulation on several emulators yields problems in combination with common cartridges and other I/O devices but should work ok as standalone cartridge. Results may vary here.


==Tech==
==Tech==

Revision as of 00:05, 14 June 2010

RAM Expansion Unit also known as REU was produced and sold by Commodore. This rather popular device is well covered on the net currently and also emulated in software and hardware (e.g. by the 1541 Ultimate) pretty well. The large Commodore version was followed by a CLD version and the CMD clones which all used a CSG8726 as controller chip also called REC. There are apparently two mounting case forms of the REC. The square one is said to be more common here.

The REU is capable of initiating DMA transfers on request allowing storing, fetching and swapping memory with the C64 main memory. While the C64 is not able to natively access the REU additional memory and programs need to utilise it especially the REU DMA is able to transfer memory extremely quick making it even a valid device for in main C64 memory moving.

So far 128, 256, 512, 1024, 2048 and 16384 kb (yes, that's 16MB using a 1541u) were spotted at the expansion port.

The REU is using up all of the IO-2 area from $DF00 - $DF0F and is mirroring that register range each $20 bytes. Cartridges operating at $DF00 will collide with the REU. Known to work in parallel using a port expander are Retro Replay when using a ROM supporting the REU memory config and Super Snapshot while Expert Cartridge and Kernel ROM replacements (incl. ExOS and StarDOS cartridges) should work as well.

Emulation

Unfortunately emulation on several emulators yields problems in combination with common cartridges and other I/O devices but should work ok as standalone cartridge. Results may vary here.

Tech

Binaries

As you can see below the REU topic is well covered all around. The binary archive for the REU is under construction. Please send anything we may miss to by email.


Weblinks

Pages in category "REU RAM Expansion Units"

The following 3 pages are in this category, out of 3 total.

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Media in category "REU RAM Expansion Units"

The following 12 files are in this category, out of 12 total.

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