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**82395SX     Smart Cache                                     12/17/90
***Notes:...
**82396SX     Smart Cache                                     12/17/90...
**82485       Turbo Cache (and 485Turbocache)                      c90...
**82489DX       Advanced Programmable Interrupt Controller    10/12/92...
**82495DX/490DX DX CPU-Cache Chip Set                           <Sep91...
**82495XP/490XP Cache Controller / Cache RAM (for i860)       06/05/91...
**82496/491     Cache Controller / Cache RAM (for P5 Pentium) 03/22/93...
**82497/492   Cache Controller / Cache RAM (for P54 Pentium)    <Nov94...
**82498/493   Cache Controller / Cache RAM (for P54 Pentium)    <Nov94...
**
**Later chipsets (basic spec):
**440 series:...
**450NX  (?)            06/29/98:...
**?????  (Profusion)    c:99...
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*Headland/G2...
**HT44          Secondary Cache                                c:Jun92
***Info:
The  HT44 is  a  look-aside write-through,  80486SX,  486DX or  486DX2
secondary cache  controller. It is  packaged in an  inexpensive 84-pin
plastic-leaded chip carrier (PLCC).

Architecture
With  its look-aside architecture,  the HT44  fits beside  the CPU-to-
Memory bus  and not in  the data path.   Therefore, once the  HT44 has
been designed  into a  486 system, it  can be populated  for secondary
cache systems or left vacant for non-secondary cache systems. The HT44
is direct-mapped to the available address space.

Performance
The  HT44  has a  number  of  performance  enhancing features.   These
include zero-waitstate burst line fills  to the 486 on secondary cache
hits, and simultaneous 486 and secondary cache updates on read misses.

Memory Configurations
The HT44 supports  cache sizes from 32KBytes to  1MB. Both synchronous
and asynchronous  SRAMs are supported.  25ns SRAMs are  sufficient for
zero-wait-state operation at 33MHz.

Chip Set Support
The HT44 can,  be implemented with minimal glue logic  in a 486 system
with the  HTK340 (code  name Shasta) chip  set.  The registers  in the
HTK340  allow  for programming  of  non-cacheable and  write-protected
areas of  memory. The  HTK340 will support  the HT44  with synchronous
SRAMs only.   Future Headland chip sets will  support both synchronous
and asynchronous SRAM designs.

The HT44  can also be used  with some third-party  chip sets, however,
additional glue logic may be required.

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**TACT83000   AT 'Tiger' Chip Set (386)                            c89
***Info:...
***Configurations:...
***Features:
o   High-Speed 1-um CMOS Technology Supports System Speeds up to 
    33 MHz
o   Fully AT-Compatible 386 Three-Chip SX, Four-Chip DX Solutions
o   Only Four Additional Logic Chips Needed
o   Major Features Programmable Through Software
o   TACT83442 Memory Control Unit (MCU)
    - Cascadable up to Eight Devices
    - Address Range of up to 32M Byte Per Device, 256M Byte Fully 
      Cascaded
    - Supports 256K-, 1M-, and 4M-Bit DRAMs in Normal, Page, Word-
      interleave, and Page Block-interleave Modes
    - Programmable DRAM Timing Parameters
    - Supports up to Two Memory Banks for 32-Bit Systems and Four 
      Banks for 16-Bit Systems
    - Can Directly Drive up to 36 DRAM Devices
    - Shadow RAM Available Between 0C 0000h and 0F FFFFh
    - Contains Global Page Mapping RAM Allowing Remap of 
      - 64K-Byte Memory Blocks Above 1M Byte
      - 16K-Byte Memory Blocks Below 1M Byte
o   TACT83443 AT Bus Interface Unit (ATU)
    - Internal Clock Switching Between Two Independent Frequencies 
      Controlled by Software
    - Asynchronous AT Bus Interface With Write Buffer Option
    - Full AT Direct-Drive Capability
    - Extended Direct Memory Access Mode for 32-Bit Operation
    - Fast CPU Reset and A20 GATE Modification
    - Numeric Processor Interface for 387SX, 387DX, and Weitek 3167
    - Integrates All Essential AT Peripherals
    - Real Time Clock With 128-Byte CMOS RAM
o   TACT83441 Data Path Unit (DPU)
    - 8- and 16-Bit Data Bus Sizing
    - Data Path Cascadable to 32 Bits
    - Write Buffer Capability for AT Bus Access
    - Supports Posted Write Operations From Cache Controller
    - Parity Generation and Checking Logic

**TACT84500   AT Chip Set (486, EISA) [no datasheet, some info]    c91...
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