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.

The were notable in 1986 as being the first company to reverse-engineer IBM's EGA to produce their own EGA chipset, which they then sold to numerous graphics card manufacturers.

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.

C&T chipsets in chronological order:

Motherboard Chipsets Graphics Card Chipsets
P82C100/P82C101 XT chipset (1987)
P82C211 NEAT chipset (1987)
CS8230 386 chipset (1989)
CS8235/CS8236 SCAT chipset (1989)

CS8240 EGA chipset (1985)
CS82C435 Enhanced Graphics Controller (1987)
82C441 VGA Controller (1987)
82C451 VGA Controller (1990)
82C455 VGA Controller (1990)
82C456 VGA Controller (1990)
82C480 VGA Controller (1990)
82C481 VGA Controller (1992)
82C611/82C612 Micro Channel Interface (1993)

MotherboardChipsets

P82C100 / P82C101 XT Chip

Launched: October 1987
Bus: 8-bit ISA

 

"Chips and Technologies Inc. announced last week a microprocessor system logic chip that the company said is likely to accelerate the cloning of IBM's PS/2 computer line.

The 82C100 chip, scheduled for volume shipment by October, will offer a 25 percent speed improvement over the IBM PS/2 Model 30, according to Chips and Technologies. The chip supports the Intel 8088 and 8086 CPUs as well as the NEC V20 and V30 microprocessors, which emulate the Intel chips.

Including support chips for the 82C100, a Model 30 compatible can be assembled using fewer than 25 components, not including memory chips, compared to more than 63 components for IBM's Model 30, the company said.

Costing $51.30 in quantity, the 82C100 chip could be used to produce a Model 30 clone to sell for under $1,000, said company spokesman Sikander Naqvi. The company will also offer a set of support chips to make up a Model 30-compatible motherboard, he said.

Although the Model 30 has few features that distinguish it from its IBM XT predecessor, there is a strong demand for the computer, said Naqvi. Compatible chip sets for the higher performance PS/2 Models 50, 60, and 80 are also planned, he said. Chips and Technologies hopes to have a Model 50-compatible chip set ready for demonstration in November.

"The significance of these chips is how easy this will make it for manufacturers to get to the market quickly with PS/2 clones," said Nancy Magoun, industry analyst for Dataquest, Inc.

Still unknown is how IBM will respond to the clone chips, according to Magoun. IBM has made it known that it intends to use every legal means to protect its new PS/2 architecture.

Chips and Technologies also unveiled its 82C101, a chip for creation of IBM PC XT compatibles. The chip supports the 8088 and V20 microprocessors and, in conjunction with supporting chips, permits an IBM PC XT clone to be built using fewer than 13 chips plus memory, the company said."
InfoWorld, July 1987

 

P82C211/212/215/206 286 NEAT Chipset

Launched: 1987
Bus: ISA

The "New Enhanced AT", or "NEAT" chipset arrived in 1987. See my separate page for more details on this.

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:

Datasheet

CS82C235 / CS82C236 SCAT Chipset

Launched: 1989
Bus: ISA

The CS8235 was essentially the NEAT chipset all embedded into a single IC, F82C235. Chips & Technologies also released a version for the 386SX called SCAT-SX (or SCATsx) with the IC being F82C236, since the chipset itself was designed for 286 and 386SX motherboards.

The SCAT chipset in both forms supported the LIM/EMS 4.0 standard, able to access up to the full 286 limit of 16 MB of RAM with support for BIOS ROM shadowing.

Motherboards known to have used this chipset are:

  • JCS 286/SCAT JC1080C 527/2 (JC Information Systems Corp.)

EMM386 Driver for SCAT chipset.

 

Graphics Card Chipsets

CS8240 Chipset

Launched: 1985
Bus: ISA

The CS8240 chipset was C&T's crowning glory in late 1985. C&T openly stated that it reverse-engineered the [IBM] EGA by removing the silicon chips from their DIP packages and making photographic enlargements of the circuits, then working backwards from the photos to logic diagrams. C&T patterned its own copies with a few changes - all perfectly legal before the Silicon Copyright Act of 1984. One penalty for such slavish copying is that all of IBM's bugs came as part of the package.

The C&T chip set did little to improve on IBM's EGA, which is incompatible with the monochrome adapter and CGA except on a BIOS level.

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:

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:

Datasheet

82C441 VGA Controller (1987)

Launched: 1987
Bus: ISA
Supports: MDA, Hercules, CGA, EGA and VGA

The 82C441 was a single-chip solution for graphics card vendors, that provided up to 800 x 560 resolution in 16 colours, and 132-column text mode. It also supported 752 x 410 and the VGA standard of 640 x 480.

It was used on the ATI EGA Wonder VIP.

82C451 VGA Controller (1990)

Launched: 1990
Bus: ISA/EISA or MCA
Supports: MDA, Hercules, CGA, EGA and VGA

The 82C451 was a single-chip solution for graphics card vendors, that provided up to 800 x 600 resolution in 16 colours, and 132-column text mode.

Graphics cards that used this chipset include:

Datasheet

82C455 VGA Controller

Launched: 1990
Bus:
Supports:

Datasheet

82C456 VGA Controller

Launched: 1990
Bus:
Supports:

Datasheet

82C480 VGA Controller

Launched: 1990
Bus:
Supports:

Datasheet

82C481 VGA Controller

Launched: 1992
Bus: ISA, EISA, MCA
Supports:

The 82C481 was a True Color Graphics Accelerator chipset.

Datasheet

82C611 / 82C612

Launched: 1993

An interface for the Micro Channel Architecture (MCA) to allow MCA peripheral card design to have most of the interface logic on a single set of chips.

Datasheet