Bard's Tale III and Kid Niki ran in mode without stating this in the documentation, using the autoboot and the 's faster disk access. The vast majority of games simply ran in C64 mode. Browse 1 Image ». Commodore Commodore International Limited Commodore.
Fans: 0 Become a Fan. Description Edit History. Technical Overview The C's complex architecture includes four differently accessed kinds of RAM, two or three CPUs, and two different video chips for its various operational modes. The Commodore , released in , was the last 8-bit computer of the Commodore line, after which, the company focused on IBM-type machines and other designs.
The Commodore was pursued by Commodore to increase compatibility and versatility, in the aftermath of the departure of Jack Tramiel for Atari months earlier. The Commodore had to compete with the Atari ST line. To that end, under lead engineer Bill Herd, Commodore produced something that was more versatile and capable than the original 64, and more stylish as well. By: Justin Stoltzfus Contributor, Reviewer. By: Satish Balakrishnan. The 's power supply was vastly improved over the 64's unreliable design, being larger and equipped with cooling vents and a replaceable fuse.
The primary CPU, the , was a slightly improved version of the capable of being clocked at 2 MHz. The two processors could not run concurrently, thus the C was not a multiprocessing system.
The C64 mode can be accessed in one of three ways:. This feature faithfully duplicates the C64 behavior when a cartridge such as Simons' BASIC is plugged into the port and asserts either of these lines, but unlike the C64, where the Memory-map changing action of these lines is implemented directly in hardware, the C's Z80 firmware startup code polls these lines on power-up and then switches modes as necessary.
C native mode cartridges are recognized and started by the kernal polling defined locations in the memory map. C64 mode almost exactly duplicated the features of a hardware 64; many of the 's additional features were disabled or unavailable in this mode. The 4 cursor keys at the top of the keyboard were unrecognized, forcing the user to use the 64's cumbersome shifted key arrangement, which were included at the bottom of the keyboard. Also ignored were the 's numeric keypad and added top-row keys the only top row keys that were functional in 64 mode were the f1-f8 keys above the keypad.
Some of these features could be turned back on by user software but most commercial programs would ignore them at best, or be completely nonfunctional with these user "wedge" programs in memory. This memory-mapped register, unused in the C64, determined the system clock rate. Since this register was fully functional in C64 mode, an inadvertent write could scramble the column display by switching the CPU over to 2—MHz, at which clock rate the VIC-II video processor could not produce a coherent display.
Fortunately, few programs suffered from this flaw. By using the higher clock rate during the vertical blank period, standard video display was maintained while increasing overall execution speed by about 20 percent. Thus, checking the location's value after writing to it will reveal the actual hardware platform.
Another feature of the memory management unit was to allow relocation of Zero page and the Stack , which, thanks to the Direct Page register. Late in , Commodore released to the European market a new version of the C with a redesigned chassis. Called the Commodore D , this new European model featured a plastic chassis with a carrying handle on the side, incorporated a disk drive into the main chassis, replaced the built-in keyboard with a detachable one, and added a cooling fan.
The keyboard featured two folding legs for changing the typing angle. The DCR model featured a stamped steel chassis in place of the plastic version of the CD with no carrying handle , a modular switching power supply similar to that of the CD, as well as a removable keyboard and internal floppy drive.
On the mainboard, Commodore consolidated some of the components to save production costs and replaced the video controller with the more technically advanced MOS Technology which was also fitted to a few D-models. As a cost-saving measure, the cooling fan that was fitted to the D model was removed, although the mounting provisions on the power supply subchassis were retained.
The increase in video RAM made it possible, among other things, to generate higher-resolution graphics with a more flexible color palette, although little commercial software took advantage of this capability.
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