Commodore 65

Commodore 65

C65 with the case open

Labeling on the mainboard

The Commodore 65 ( C65 for short ) is a projected 8-bit home computer from the US manufacturer Commodore International , which was never ready for series production and which was to come onto the market in 1991 as the successor to the market-leading Commodore 64 . The C65 should be software-compatible with the previous model and for this purpose with a further development of the proven 8-bit microprocessor MOS Technology 6502 , 128 KB working memory (RAM), 128 KB permanent memory (ROM) as well as with improved special modules for the image and Be equipped with sound output. An expansion of the functionality of the interfaces was also planned. The development of a new dialect of the BASIC programming language called Commodore BASIC V10.0 was commissioned to operate and program the computer . In addition, the C65 should have a new housing design including an integrated 3½-inch floppy disk drive.

In order not to create any profit-reducing in-house competition for their own 16-bit home computers, above all the Amiga 500 and the Amiga 500 Plus , the manufacturer decided not to launch the computer, which is known internally as the C64DX Development System . Therefore, the C65 never got beyond the planning stage and there are only a few prototypes that have a high collector's value due to their rarity and the importance of the previous model for the history of home computers.

history

After the insolvency and liquidation of Commodore in 1994 , all prototypes of the C65 built so far were sold, which today are without exception in the hands of collectors as sought-after and valued rarities. The information about the number of pieces in circulation varies between 50 and 1000 pieces. However, a lot of no more than 250 devices is realistic.

It is not entirely clear why Commodore developed the C65, since a very similar device already existed in 1986 with the Amiga 500. It is assumed that the unbroken success of the Commodore 64 made a dedicated successor seem inevitable, as the Amiga series was not compatible with the software and hardware of the 64 series. It would certainly have been a purchase argument for many users if they had been able to continue using the existing equipment and programs. Commodore bought the Amiga almost completely developed. The Amiga was initially intended as a game console. As is well known, Commodore changed the design to a full-fledged home computer, which in mutually compatible versions should also be sufficient for demanding office applications. But with the exception of professional video applications, the Amiga never really found its way out of the home computer niche. For the C64, however, you needed more a further development than a successor. The first plans for its development were drawn up before the Amiga was purchased.

On April 22, 2015, the Museum of Electronic Games & Art announced in a blog post that they were currently working on a clone of the Commodore 65 under the name Mega65 . In the first half of 2018, 20 development machines produced by the project are to be given out to developers, former C65 engineers, influencers and journalists from retro magazines. The CPU is said to be 50 times faster than the original.

Technical characteristics

The prototypes of the C65 are all in different, very early stages of development . For example, the built-in Commodore BASIC V10.0 is still very faulty and in some cases still has significant gaps. The intended compatibility with the C64 is still far from being achieved. Actually, these pre-production models were only intended as samples for developers and the press.

Start screen of the C65

Opened Commodore 65 prototype, the floppy disk drive can be seen on the right

features

• Processor: CSG 4510 ("Victor")
• Clock frequency: 3.54 MHz
• 128 KB ROM
  • contains: C64 Kernel, BASIC 2.2, BASIC 10.0, DOS, character sets with country-specific keyboard layout
• 128 KB RAM , expandable up to 8 MB with a RAM card
• Video chip: CSG 4567 ("Bill" or VIC-III )
  • supports all video modes of the VIC II
  • Max. 256 colors from a palette of 4096
  • Text modes with 40/80 characters × 25 lines
  • Graphics resolutions from 160 × 200 to 1280 × 400 pixels
  • Complete C64 graphic mode included
  • can be synchronized with an external video source ( genlock )
  • integrated DMA controller ( bit blit )
• DMA custom chip "DMAgic"
• Floppy Disk Controller ("FDC") F011 (CSG 4571 or 4581)
• Keyboard with 77 keys and separate cursor block
• SID CSG8580 with 2 × 3 voices (channels mixed, no separate stereo output)
  • separate control for volume, filter and modulation
• Expansion options: module slot, user port, memory expansion connection on the bottom
• Input / output: RGB, module slot, user port, two joystick ports, television connection (TV modulator), RGB, video port with composite and S-video signal (also includes audio), serial port for printer and floppy disk drives

C65 in action

processor

With the CSG 4510, a further development of the MOS 65CE02 was used as the processor , since the Motorola 68000 , which was current at the time , could not guarantee compatibility with the C64. The processor is clocked at 3.54 MHz and has two CIAs of type 6526 integrated. The original 8-bit instruction set was expanded to include a few 16-bit RMW instructions , and relative jumps and subroutine calls can also be addressed with a 16-bit offset. The CSG 4510 is thus an 8-bit CPU with 16-bit functions. Since the complete instruction set from the MOS 6502 is still included, the C65 is largely binary compatible with the C64. Only some known illegal opcodes of the MOS 6502 no longer work here, but the CSG 4510 has other undocumented features.

Chipset

Similar to the Amiga, the C65 has different co-processors with special tasks, and just like the Amiga, it has given its own name:

• VICTOR: CSG 4510 main processor
• BILL: VIC-III (graphics processor) CSG 4567
• DMAGIC: DMA controller CSG 390957
• FDC: CSG 4571 or 4581 floppy disk drive controller
• programmable PAL-ICs ELMER (from Rev. 2A) and IGORI (from Rev. 2B to the right of Elmer). From Rev. 3 combined to one IC.

(CSG = Commodore Semiconductor Group, previously known as MOS Technology )

• Custom chips
• 

  Victor

• 

  Bill

• 

  Elmer

• 

  FloppyDiskController

Another highlight is a UART with a programmable baud rate generator , which can reach speeds up to a MIDI clock. This should make the C65 ready to operate modems at high data rates or to use it as a sequencer or even as an instrument in a MIDI setup.

software

There are almost no native C65 programs. Similar to the C128 , the C65 should be fully compatible with the C64. However, this was only partially successful, and only about 60–70% of the C64 programs can run on the C65. This is because, in contrast to the C128, which contains a full-fledged C64, the C65 emulates a C64 on one and the same hardware. Problems are mainly caused by games and demos that make excessive use of common programming tricks of the C64. Most of the new capabilities of the C65 can also be used in C64 mode. As with the C128, a machine language monitor is also available. You can switch between the individual operating modes (C65, C64, Monitor) at any time without having to restart. The built-in BASIC interpreter of the C65 mode is version V10.0.

There are a handful of small demo programs that run natively on the C65 and demonstrate the advanced graphics capabilities for the time.

ROME

The ROM contains 128 KB of BASIC 2.2, BASIC 10.0, DOS and a monitor. If necessary, the corresponding memory area is shown in the Kernal via bank switching .

BASIC

The Commodore BASIC has always been based on the first BASIC interpreter from Microsoft from 1977 . The C64 had version 2.0. This has been slightly adapted as BASIC 2.2 and is included in the C65 (the datasette routines were deleted due to the lack of connectivity, the internal 3.5 ″ floppy drive was set as the standard drive instead). It is contained at 20 KB in the 128 KB ROM of the C65. Although the BASIC 10.0 implemented in the C65 sounds like a considerably expanded version due to the version number, all commands have never been implemented, and so the command set has large functional gaps.

BASIC 10.0 has a lot in common with BASIC 7.0 on the C128. In addition, there are a number of new interesting commands:

GENLOCK      (Videosynchronisation)
MOUSE/RMOUSE (Maus)
TYPE         (Zeigt eine sequentielle Datei auf dem Bildschirm an)
FIND/CHANGE  (Suchen und Ersetzen in Strings)
FRE(0|1|2)   (zeigt den freien Speicher der jeweiligen Bank an)
PALETTE      (Farbdefinition)
DMA          (unklar, DMA-Operationen)

The following commands issue a ? UNIMPLEMENTED COMMAND ERROR :

PAINT
PASTE
CUT
LOCATE
SCALE
WIDTH
QUIT
OFF
SET
VIEWPORT

As with BASIC 7.0, the function keys are programmable. They are assigned as follows by default:

F1:   Umschaltung 40/80 Spalten
F2:   löscht alles unterhalb des Cursors
F3:   schreibt DIR an die Position des Cursors
F4:   schreibt DIR „*=PRG“ an die Position des Cursors
F5:   setzt den Cursor an den Anfang des vorherigen Wortes
F6:   schreibt KEY 6 an die Position des Cursors (vermutlich noch nicht implementiert)
F7:   setzt den Cursor an den Anfang des nächsten Wortes
F8:   schreibt MONITOR an die Position des Cursors
HELP: schreibt HELP an die Position des Cursors

graphic

The graphics are comparable to the performance of the first Amiga. The CSG 4567 graphics processor, also known under the name "Bill" or "VIC III", with an integrated MMU is new . The chip can display 256 colors in 16 brightness levels. This results in a palette of 4096 different colors, of which only 256 can be displayed at the same time. The MMU can be programmed separately and independently in a similar way to the Amiga Blitter . The blitter itself is integrated in the "DMAgic" DMA controller. This resulted in unique possibilities in the programming of dynamic graphic and color effects at the time. The resolution can be up to 1280 × 400 pixels (interlaced). The display of 256 colors at 320 × 200 pixels was on a par with a modern PC at the time. Even the Amiga could only display 16 or 32 colors in normal mode. The display can be output to a television via a built-in RF modulator or a composite output. An RGB output is available for better resolution monitors, which promises a much higher image quality.

A Display Address Translator (DAT) helps to translate the complicated addressing of coordinates in the graphics memory.

Graphic modes

Non-interlaced

• 320 × 200, 256 colors (8 bit planes)
• 640 × 200, 16 colors (4 bitplanes)
• 1280 × 200, 4 colors (2 bitplanes)

Interlaced

• 320 × 400, 256 colors (8 bit planes)
• 640 × 400, 16 colors (4 bitplanes)
• 1280 × 400, 4 colors (2 bitplanes)

Sound

The sound output (sound) has also been improved. The C65 was given two SIDs with three, so a total of six independent voices. Unfortunately, no two-channel technology ( stereo ) was provided for the prototypes , because the signals were mixed internally.

DOS

In contrast to most previous 8-bit computers from Commodore, the C65 has a complete DOS , which controls the built-in 3.5 ″ floppy. The drive is compatible with the VC1581 and its MFM format . The diskettes have a storage capacity of 880 KB. However, since this format was not very widespread among the C64 owners at the time, the C65 also has the already known serial port for Commodore floppies. This can also be used to operate a VC1541 , as used for the C64, on the C65.

The programmer of the C65 operating system Dennis Jarvis used the DOS of the old Commodore drives with IEEE-488 connection as the basis for the DOS of the C65. It can handle only two drives, including the internal one. The F011 controller for drives can address up to seven external drives, each of which must contain an IC called F016 (CSG 4101). Since the planned external 1565, an additional drive for the F011 "Fast Serial" port, has no further connections, it can be assumed that the C65 should be able to address a maximum of one external drive.

Interfaces

The C65 has the usual interfaces of the C64, and there is also a DMA port for memory expansion. As with the Amiga 500, the latter is attached to the circuit board from below via a flap in the floor. The built-in floppy disk drive is connected via a port called "Fast Serial", serial drives from Commodore can be connected via the usual IEC port. A connector for a genlock was also provided. Only the port for the datasette of the C64 is no longer available, and the user port lacks the 9 volt AC voltage, which could lead to problems with some extensions. The expansion port is 50-pin and identical to that of the C16 . A special adapter, the so-called "widget" board, provided the usual 44-pin C64 expansion port, with which simple games and program modules could be played. However, special extensions such as Freezer could not be run.

documentation

A manual does not exist, only some documents from development with technical descriptions ("C65 Technical Specification").

market

The price at market launch should be somewhere between that of the C64 (≈300 DM / ≈150 euros ) and that of the Amiga 500 (≈1000 DM / ≈500 euros). The prototypes were then sold for around 600 DM (≈300 euros). However, there is hardly any software that was written directly for the C65 and the compatibility with the C64 was around 60–70%.

Although these are outdated prototypes with by no means a complete range of functions, high and steadily rising collector prices are being paid for a C65 today: While a functional C65 in the online auction house eBay still sold for € 6,060 in December 2009 , a device with missing bricks sold for over $ 20,100 in October 2011 on the same platform. In April 2013, a C65 was sold on eBay for € 17,827. Most of the owners of a C65 are collectors and many are even known by name in the scene. On February 15, 2015, another C65 was sold on eBay for € 20,050 and on October 18, 2015, a slightly scratched copy even reached € 22,827. A working copy with serial number 000004 was sold on eBay on November 6, 2016 for € 15,605. The auction of another fully functional C65 prototype with memory expansion (serial number 000016) ended on November 8, 2017 with a new highest bid of 81,450 euros.

emulation

The C65 can be emulated by the MESS emulator and Hi65.

literature

• Rainer Benda: The Downfall of Commodore , Scriptorium Verlag, Munich 2007. ISBN 978-3-938199-10-7 .

Web links

Commons : Commodore 65  - Collection of pictures, videos and audio files

• Information and pictures about the C65 at computer collection vienna
• Article about the C65 at Old-Computers.com
• The Commodore 65 (English)
• 8-bit nirvana: Commodore 65
• German C65 page with lots of photos and information
• Toxic Waste's Commodore C65 Information Page
• Further information in the CBM Museum
• C65 in detail: Part 1: Theory , Part 2: Practice

Individual evidence

1. ↑ Introducing the MEGA65 (8-bit) computer | MEGA - Museum of Electronic Games & Art. Retrieved August 20, 2020 . 
2. ↑ project Mega65. Retrieved February 2, 2018 . 
3. ↑ Happy Computer: 09/1989 The new C 64 is coming! Retrieved August 20, 2020 . 
4. ↑ 18-year-old computer brings you 6,060 euros. Retrieved on August 20, 2020 (German). 
5. ↑ Very rare prototype Commodore C65 aka C64DX aka C90
6. ↑ Ultra rare Commodore 65 / C65 / DX64 prototype, working, serial # 22
7. ↑ Ultra RARE: Commodore 65 prototype, aka DX64 or C90 - fully working, see video. Retrieved on August 20, 2020 (Swiss Standard German). 
8. ↑ Commodore 65 prototype, ULTRA RARE! aka C65 / DX64 - clean and working! | eBay. In: eBay. Retrieved November 6, 2016 . 
9. ↑ Commodore C65: Prototype for the C64 successor - Ebay auction ended at 81,450 euros. Retrieved November 11, 2017 . 
10. ↑ Hi65: a high-level Commodore 65 emulator ( English ) Devil Master. Retrieved February 12, 2019.