TMS34094 Datasheet, PDF (1/38 Pages) Texas Instruments – ISA BUS INTERFACE

TMS34094
ISA BUS INTERFACE
• Simplifies Design of High-Performance ISA
PC Graphics Systems
• Single-Integrated Circuit Interfaces
TMS34020 to ISA Bus
• Conforms to ISA Portions of the EISA
Rev. 3.11 Specifications
• Internal Data Bus Transceivers
• Register Configurable I/O Mapped or
Memory-Mapped Interface
• Register Configurable as an 8- or 16-Bit ISA
Memory-Mapped Device
• Configurable TMS34020 Address Space
Decoding
– VRAM Shift Register Transfer Decoding
– VRAM Mask Write and VRAM Color
Register Write Access Decoding
• VGA Passthrough Support
• Operating Free-Air Temperature
. . . 0°C to 55°C
SPVS006A – FEBRUARY 1992 – REVISED JUNE 1992
160-PIN PC PLASTIC QUAD-FLAT
PACKAGE (EIAJ)
(TOP VIEW)
160
121
1
120
40
41
81
80
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.
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.
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Copyright © 1992, Texas Instruments Incorpo-
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