Commodore 64 Hardware
The 6510 microprocessor, with 8-bit MOS Technology is used by the Commodore 64. It is a derivative which is very close to the 6502 microprocessor containing the internal I/O port 6-bit which is used for two purposes in the C64. It is used in the datasette tape recorder for operational purposes and for bank switching the ROM of the machine in as well as out of the address space of the processor. Out of the RAM totaling to 64 KB, around 38 KB invested in the Commodore BASIC 2.0 that is built within in the C64.
MOS technology VIC-II used in the C64 has a number features. The graphics modes in a two bit map, the capabilities for scrolling, the hardware sprites totaling to eight in number per scaline, colors totaling to16 etc are featured in the VIC-II graphics chip. Just like the PET models in the Commodore, the forty columns are the text mode features that are standard. Encoding of the built in characters is offered by PETSCII, and it is not standard. A sub form of the application is ASCII - 1963, a form that has now been extended in versatility. As far as the VIC-II chip goes, one of the unique features is the border around the screen shots.
Different registers of hardware are used for re setting the software, by getting the 'interrupts' utilized for accurate and precise time setting. Within the available borders there is scope for placing graphics, thus enabling utilization of the entire screen. For sound, the MOS technology enhanced SID is being used. Three channels are embedded in the SID chip and each of the channels has the ability to filter, modulate rings and manage their own ADSR envelope generator.
The SID chip was developed by Bob Yannes. The company Ensoniq was later co founded. Kjell Nordbø, Rob Hubbard, David Dunn, David Whittaker, Martin Galway, Chris Hülsbeck, and many more composers and programmers have played a pivotal role in raising the application standards. The chords available are played as arpeggios due to the three channel availability. The characteristic lively sound of the C64 is coined accordingly. The 4 bit digitized volume playback empowers the master volume for an upscale performance with consistent updating. Filtering the two SID channels as well as the 8 bit audio samples that are four channeled became a possibility only by the year 2008. The 8580 and the 6581 are the SID chip versions known.
It was in the Commodore and the C64C earliest versions that the original "breadbox", C64's 6581 MOS technology was used. In the year 1987, the MOS Technology 8580 replaced the 6581. However, the crisp quality of sound of the 6581 was preferred by many of the Commodore 64 fans. There's many a strong front that has impressed fans of the Commodore 64 and this guarantees that the cult following is hardly ever dented despite continuous tech developments all around us.
Voltage supply is one of the major differences between the 6581 and the 8580. A nine volt supply is used in the 8580 and a 12 volt supply is used in the 6581. In case needed, certain modifications can also be made for using the 6581 in the board of the C64C and this flexibility, and realm of possibility never ceases to amaze.