Editing Commodore 65 (section)

== Technical specifications ==
* The [[Central processing unit|CPU]] named [[CSG 65CE02|CSG 4510]] R3 is a custom [[MOS Technology|CSG]]<ref>Commodore Semiconductor Group, previously known as [[MOS Technology|MOS Technology, Inc]]</ref> [[CSG 65CE02|65CE02]] (a [[MOS Technology 6502|MOS 6502]] derivative), combined with two [[MOS Technology 6526|MOS 6526]] complex interface adapters (CIAs), a UART serial interface, and a memory mapper to allow for an addressable space of 1&nbsp;MB<ref name=zm_c65man/>
* 3.54 [[megahertz|MHz]] clock frequency (the C64 runs at 1&nbsp;MHz)
* A new [[MOS Technology VIC-III|VIC-III]] [[graphics chip]] named CSG 4567 R5, capable of producing 256 colors from a palette of [[Color depth#12-bit color|4096 colors]]; available modes include 320×200×256 (8), 640×200×16 (4), 640×400×16 (4), 1280×200×4 (2), and 1280×400×4 (2) ( X×Y×color depth, i.e. number of colors ([[bit plane]]s) )
** Supports all video modes of [[MOS Technology VIC-II|VIC-II]]
** Text mode with 40/80 × 25 characters
** Synchronizable with external video source ([[genlock]])
** Integrated [[Direct memory access|DMA]] controller ([[bit blit]])
* Two CSG 8580R5 [[MOS Technology SID|SID]] [[sound chip]]s producing [[stereophonic sound|stereo]] sound (the C64 has one SID)
** Separate control (left / right) for volume, filter and modulation
* 128 [[kilobyte|KB]] [[random-access memory|RAM]], expandable with up to 1&nbsp;[[megabyte|MB]]<ref name=zm_c65man/> using a RAM expansion port similar to that of the Commodore [[Amiga 500]]
* 128&nbsp;KB ROM
* Heavily improved BASIC: [[Commodore BASIC|Commodore BASIC 10.0]] (the C64 has the relatively feature-weak BASIC 2.0, which was almost 10 years old by this time.)
* One internal 3½" [[Double-sided disk|DS]][[Double density|DD]] [[floppy disk]] drive
* Keyboard with 77 keys and an inverted T directional cursor block

=== Ports ===
Left side:

* Power +5&nbsp;V DC at 2.2&nbsp;A and +12&nbsp;V DC at 0.85&nbsp;A<ref name=zm_c65man/>
* 2× Control ports DE9M<ref name=zm_c65man/>

Back:

* Expansion port 50-pin<ref name=zm_c65man/>
* [[Commodore bus|CBM-488]] bus using a [[DIN connector|6-pin DIN]] for [[Commodore 1541|1541]]/[[Commodore 1571|1571]]/[[Commodore 1581|1581]]<ref name=zm_c65man/>
* User port: parallel 24-pin (without 9&nbsp;V AC)<ref name=zm_c65man/>
* Stereo 2× [[RCA connector]]<ref name="rc_c65">{{cite web|title=c65_html_1410c60e.gif|url=http://www.retrocommodore.com/retro/images/stories/c65resurrection/c65_html_1410c60e.gif|archive-url=https://archive.today/20130624191806/http://www.retrocommodore.com/retro/images/stories/c65resurrection/c65_html_1410c60e.gif|url-status=dead|archive-date=2013-06-24|date=2012-12-16|access-date=2013-06-21|publisher=retrocommodore.com}}</ref> for left and right channel<ref name=zm_c65man/>
* RGBA video [[D-subminiature|DE9F]]<ref name=zm_c65man/><ref name="gallery_c65">{{cite web|title=commodore.ca/gallery/hardware/c65.jpg |url=http://www.commodore.ca/gallery/hardware/c65.jpg |date=2011-03-29|access-date=2013-06-21|publisher=commodore.ca}}</ref>
* [[RF modulator|RF video]]<ref name=zm_c65man/>
* [[Composite video]] [[DIN connector|8-pin DIN]]<ref name=zm_c65man/>
* External fast floppy drive port — [[Mini-DIN connector|mini-DIN-8]]<ref name=zm_c65man/>

Bottom flap:

* RAM expansion<ref name=zm_c65man/>

Dimensions: ≈46&nbsp;cm wide, 20&nbsp;cm deep, 5.1&nbsp;cm high<!--2.2. Form Factor ; 1.2. System Overview--><ref name="zm_c65man">{{cite web|title=C64DX System specification|url=http://www.zimmers.net/anonftp/pub/cbm/c65/c65manual.txt.gz|date=2009-08-18|access-date=2013-06-21|publisher=zimmers.net|archive-date=2015-06-02|archive-url=https://web.archive.org/web/20150602171841/http://www.zimmers.net/anonftp/pub/cbm/c65/c65manual.txt.gz|url-status=dead}}</ref>

===Chipset names===
The custom chips of the C65 were not meant to have names like the custom chips in the [[Amiga]]. Although there are names printed near the chip sockets on various revisions of the circuit board, they were not intended as names for the chips. According to former Commodore engineer Bill Gardei,<ref name="cccom_bill">{{cite web|title=The Story Behind 'Bill' and 'Victor'|url=http://collectorcomputers.com/truthaboutbill.txt|date=2013-11-16|access-date=2013-11-16|publisher=collectorcomputers.com|archive-url=https://web.archive.org/web/20150610201234/http://collectorcomputers.com/truthaboutbill.txt|archive-date=2015-06-10|url-status=dead}}</ref><blockquote>The Legend on the PCB was to let others in the organization know [whom] to go to for advice on the chips. We did have an issue with that. But that wasn't the name of the chip at the time. The 4567 was always called the VIC-3. I can see why others outside of Commodore made the connection. But again—no—we never called these chips "Victor" or "Bill".</blockquote>The custom chips for the C65 are:

* CSG 4510: processor (commonly called "Victor" after Victor Andrade)
* CSG 4567: VIC-III graphics processor (commonly called "Bill" after Bill Gardei)
* CSG 4151: DMAgic DMA controller (designed by Paul Lassa)
* F011C: FDC (floppy disk controller, also designed by Bill Gardei)

The C65 also contains one or two programmable logic arrays depending on the version:

* ELMER: PAL16L8 (C65 versions 1.1, 2A, 2B), PAL20L8 (C65 versions 3–5)
* IGOR: PAL16L8 (C65 version 2B only)

===Graphics subsystem===
{{No sources|section|date=April 2024}}

The main memory of the C65 is shared between the graphics subsystem and the CPU. The memory clock runs at almost twice the speed of the C64. To further increase the bandwidth of the graphics subsystem, the memory is divided into 2× 8-bit wide banks of 64&nbsp;Kbyte which can be accessed by the CSG-4567 simultaneously. This provides an effective video-DMA bandwidth of 7.2&nbsp;MB/s which is the same specification as the original 16-bit Commodore Amiga chipset (OCS/ECS). The CPU can use up to half the available bandwidth, since it can only access a single 8-bit bank at a time. In higher demanding video modes, the CPU is slowed down due to increased cycle stealing from the video controller.

====Enhanced VIC-II modes====
In addition to having all of the C64 video modes, the CSG-4567 also supports several new character attributes such as "blink" or "bold" and can display any of the new or old video modes in 80 column or 640 horizontal pixel format, as well as the older 40 column 320 pixel format [6]. These enhanced "VIC-II" modes take up to 16&nbsp;KB of system RAM. The sprite capabilities in all VIC modes are equivalent to the C64.

=====Bitplane modes=====
A new "bitplane" video mode was added to allow the displaying of true bitplane type video, with-up to eight bitplanes in 320 pixel mode and up to four in 640 pixel mode. The CSG-4567 can also time-multiplex the bitplanes to give a true four-color 1280 pixel picture. Vertical resolution is maintained at 200 lines as standard, but can be doubled to 400 with interlace [6]. The VIC-III bitplane modes take up to 64&nbsp;KB of system RAM in non-interlaced or 128&nbsp;KB RAM in interlaced (400 line) modes. Since the C65 is equipped with only 128&nbsp;KB in its basic configuration, these modes would consume the entire RAM, and are therefore only useful in a RAM expanded system. On a basic system, it would probably have made more sense to write software which uses less demanding resolutions with fewer bitplanes—partly because this would consume less of the confined RAM space, but also because more bitplanes would demand a higher video DMA bandwidth and consequently slow down the CPU as a result.

====DAT and Blitter====
The bitplanes on the C65 are organized in a less straightforward manner than e.g. on the Commodore Amiga, which organizes the bitplanes as straight rows of pixels: On the C65, the bytes within the bitplanes are organized as 25 rows of 40 or 80 stacks of 8 sequential bytes, similar to the original 320×200 VIC modes. Because this makes it harder to derive individual byte and pixel addresses from their position in the XY coordinate frame, the C65 provides a conversion mechanism in hardware called Display Address Translator (DAT).

Further aid to the programmer comes in the form of a bit-blitter, which supports

* Copy (up,down,invert), Fill, Swap, Mix (boolean Minterms) Hold, Modulus (window), Interrupt, and Resume modes
* Block operations from 1&nbsp;byte to 64&nbsp;KB

===DOS===
{{No sources|section|date= April 2024}}

In contrast to previous 8-bit computers from Commodore, the C65 has a complete DOS through which the built-in 3.5-inch floppy disk drive can be controlled. Disks used by the C65 have a storage capacity of 880&nbsp;KB and the drive is compatible with [[Commodore 1581|C1581]]. Since this format was uncommon for the former C64 owners, the C65 retains the serial IEC port for external Commodore disk drives. <!--The reminder??-->It's possible to use a [[Commodore 1541|1541]], [[Commodore 1571|1571]], [[Commodore 1581|1581]], or other similar model.

The DOS itself is based on the Commodore PET IEEE [[Commodore 8050|8250]] drive DOS. Since it can only deal with two floppy disk drives, including the internal, only one external drive may be connected to the internal floppy disk controller. Like earlier systems, up to four drives can be [[daisy chain (electrical engineering)|daisy-chained]] on the IEC port.

===Interfaces===
The C65 includes the same ports of the C64. In addition, there is a DMA port for memory expansion. The latter is attached just like on the [[Amiga 500]] via a flap in the bottom of the board.<ref name="wikipedia_file_c65">[[:commons:File:C65-open.jpg|C65 open ]]{{Circular reference|date=September 2023}}</ref> The built-in floppy disk drive is connected in parallel, serial Commodore drives can be connected via the usual [[Commodore bus|IEC port]]. A plug for a [[genlock]] was also provided. Only the port for the C64 [[Commodore Datasette|datasette]] is no longer available, and the user port missing—like the Aldi C64{{citation needed|date=May 2014}}—the 9 volt AC line. The expansion port differs significantly from all prior C64 variants and rather resembles that of [[Commodore 16|C16]].