Texas Instruments MINI MEMORY Handbuch Seite 4

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Texas Instruments
CAUTION: When you remove or insert the Mini Memory module, the computer console should be
OFF to prevent the possibility of losing or altering any data or programs stored in the module's RAM.
An importantfeature of the Mini Memory module is its capability of implementing assembly language
programs.Themoduleallowsyoutoloadyourownassemblylanguageprogramsfordirectaccessto
the programmable components in the computer (such as the TMS9900 microprocessor or the
TMS9918 Video Display Processor). Assembly language programs can also directly access devices
such as the Wired Remote Controllers or cassette tape recorders through their interface ports on the
console.
In addition, the module makes it possible for assembly language subroutines to be called form TI BA-
SIC programs. These assembly language subroutines can perform functions which would be ineffi-
cient or impossible to implement in BASIC. Program routines resident in the module's GROM and
ROM provide a convenient interface between TI BASIC programs and assembly language
programs.
Also included in the module is the EASY BUG debugging program. With EASY BUG, you can access
the memory and programmable components in the computer. EASY BUG also includes commands
for loading and storing memory-image data on cassette tape.
GENERAL MEMORY INFORMATION
Note: In the users manual, the greater than symbol (>).indicates that the following number is a hexa-
decimal (base 16) number.
The Mini Memory module contains a total of 14 K bytes of memory, consisting of 4 K bytes of battery-
powered Random Access Memory (RAM), 4 K bytes of Read Only Memory (ROM), and 6 K bytes of
Graphics Read Only Memory (GROM). Resident in the ROM and GROM are a number of routines
which add additional callable subprograms to TI BASIC and which are useful for interfacing assem-
bly language programs with TI BASIC programs.
Appendix A shows the memory organization for the computer's entire memory of the user manuel
space. The 4 K bytes or ROM in the Mini Memory module occupy the memory space from address
6000 - 6FFF (or from 24576 through 28671). Appendix B illustrates the details of the module's ROM
organization.
The 4K bytes of RAM in the module occupy the memory space from addresses >7000 through<
7FFF (or from 28672 through 32767). Appendix C shows the datails of the RAM organization when it
is used for TI BASIC files. Appendix D describes how the RAM is organized when it is used for assem-
bly language storage. The GROM occupies memory space which is not directly mapped into the
CPU memory address space. Appendices E and Pcontain information about the RAM in the Video
Display Processer (VDP).
SOURCES FOR BACKGROUND INFORMATION
A number of references can give you helpful background information as you begin to use the Mini
Memory module. These are:
1. The Texas Instruments Home Computer User's Reference Guide;
2. The Texas Instruments Home Computer TI Extended BASIC owner's manual;
3. And, if you are creating assembly language programs, the Texas Instruments Home Computer
Editor/Assembler owner's manual. This book is a complete reference guide to the TMS9900 as-
sembly language and also contains details aboutthe internal architecture of the Tl99/4 and TI99/
4A Home Computers.
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