DOS Days

Chips & Technologies, Inc.

C&T were an California-based chipset manufacturer for PC compatible motherboards, graphics cards, and peripherals such as hard disk controllers.

They were more prominent in the late 1980s, up to 80386DX era. They were later acquired by Intel in 1997, primarily for their graphics chip business.

P82C211/212/215/206 286 AT Chipset

Launched: 1986.
Bus: ISA

Supports Intel 80286 CPUs at 12 and 16 MHz. The four-chip chipset includes the following:

82C206 - Integrated Peripheral Controller
82C211 - CPU/Bus Controller
82C212B - Page/Interleave EMS Memory Controller
82C215 - Data/Address Buffer

CS8230 386 AT Chipset

Launched: 1989.
Bus: ISA/EISA or MCA.

Supports Intel 80386 CPUs at 16, 20 or 25 MHz. The eight-chip chipset includes the following:

82C206 - Integrated Peripheral Controller
82C301 - Bus Controller
82C302 - Page/Interleave Memory Controller
82A303 - Address Bus Interface
82A304 - Address Bus Interface
82A305/82B305 - Data Bus Interface x 2
82A306 - Control Signal Buffer

Motherboards known to have used this chipset are:

ECS 386/32 (Elitegroup Computer Systems)
Unknown brand 386 motherboard with cache

Data sheet

CS8240 Chipset

Launched: 1985
Bus: ISA

The CS8240 graphics chipset consisted of these four ICs:

82C431 - Graphics Controller
82C432A - Sequencer
82C433 - Attributes Controller
82C434A - CRT Controller

A number of mid-80s EGA cards made use of this chipset, including:

FCC ID: FHG5UA-XEGA
Video7 QuadEGA+

82C435 Enhanced Graphics Controller (1987)

Launched: 1987
Bus: ISA
Memory: Up to 256 KB in eight 64k x 4 DRAMs
Supports: MDA, Hercules, CGA and EGA.

The 82C435 Enhanced graphics controller chip integrated all four of the earlier CS8240 graphics chipset chips into a single 84-pin PLCC package. Its accompanying bus interface chip, 82A436, handled memory and I/O operations and came in a single 68-pin PLCC.

The 82C435 Enhanced graphics controller and 82A436 bus interface allowed third-party graphics card manufacturers to implement a 100% EGA compatible card with as few as 13 additional components. And in the spirit of IBM compatibility, the card also fully supported the older IBM graphics standards of CGA, Monochrome, and Hercules.

One feature that would be seen on competing products soon after was what C&T called 'Smart Auto-Emulation', which automatically adjusted to the graphics mode required by the application software. It could also handle dynamic reading and writing of registers without being reset, making task-switching/multi-window applications a possibility.

An enhanced CGA mode was also provisioned, allowing the display of CGA text at EGA resolution (640 x 350). In addition, other aspects of the EGA standard including a light pen interface and Feature Connector (for external video, e.g. TV-out) were also included.

The chipset supported a maximum of 256 KB of video memory for EGA modes, comprising up to eight 64k x 4 chips. This permitted resolutions of 640 x 480 in 16 colours, and 800 x 600 (larger than standard EGA, whose max resolution was 640 x 350) - these are sometimes called "Super EGA". 16k x 4 chips were not supported (so a 64 KB card is not supported with this chipset). When run in CGA modes, memory was limited to using 16 KB, and in Monochrome/Hercules text modes it was limited to 4 KB. Memory speeds supported were 100ns, 120ns and 150ns (120ns or faster is required for high-bandwidth CPU modes - see further down).

Graphics Modes supported were:

Hercules/Monochrome: 40x25/80x25 text modes, Hercules Graphics Mode-Half, Hercules Graphics Mode-Full
CGA: 40x25/80x25 text modes, 160x100, 320x200, 640x200
EGA: 320x200, 640x350, 640x480, 800x600

The chipset could be driven at up to 25 MHz dot clock if an external crystal oscillator was employed in the design. When run in 320 x 200 modes, dot clock was halved.

Performance of the 82C435 was excellent as it permitted the CPU two accesses to display memory for every four CRTC accesses, effectively doubling the memory bandwidth available to the CPU (and by translation, updating the screen twice as often). This mode could be used at up to 20 MHz video clock (standard EGA operation runs at 16 MHz).

It was used on the following cards:

Data sheet