TMS34094

ISA BUS INTERFACE

SPVS006A – FEBRUARY 1992 – REVISED JUNE 1992

POST OFFICE BOX 1443

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Copyright

rated

PRODUCTION DATA information is current as of publication

date. Products conform to specifications per the terms of Texas

Instruments standard warranty. Production processing does

not necessarily include testing of all parameters.

PC Graphics Systems

TMS34020 to ISA Bus

Rev. 3.11 Specifications

Memory-Mapped Interface

Memory-Mapped Device

Decoding

– VRAM Shift Register Transfer Decoding

– VRAM Mask Write and VRAM Color

Register Write Access Decoding

... 0

°C to 55°C

description

The TMS34094 ISA Bus Interface device, a peripheral device for the TMS34020 Graphics Processor, facilitates

the design of a high-performance graphics system for use in an ISA Bus-compatible PC. The device decodes

ISA Bus cycles and controls the TMS34020 host interface to enable read and write accesses to the TMS34020’s

local memory. In addition, the TMS34094 allows the host to access the TMS34020’s local memory via either

I/O-mapped or memory-mapped ISA Bus accesses. The capability is software configurable, simplifying design

and reducing system cost.

I/O mapped interface

The I/O mapped interface defines three I/O locations which facilitate access to the entire range of TMS34020

local memory. Two registers are used together to provide a 28-bit address to the TMS34020. The third register

acts as the data port between the ISA Bus and TMS34020 local memory. This set of three registers supports

the TMS34020’s autoincrement modes which reduce data transfer overhead. For simplifying interrupt routines,

the TMS34094 also provides read back of the address for the next host access.

memory-mapped interface

The memory-mapped interface provides four highly configurable windows between host memory space and

TMS34020 memory space. Each window has four individually configurable attributes. These include: response

as either an 8-bit or 16-bit device; begin address in the memory map of the host; begin address in the memory

map of the TMS34020; and size. Size may range from 8K bytes to 4M bytes.

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160-PIN PC PLASTIC QUAD-FLAT

PACKAGE (EIAJ)

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