Texas Instruments 99/4A - Page 5

TABLE OF CONTENTS
PAGE #
Introduction ............................................................................................................................................................ 01
System Block Diagram ................................ 02
Architectural Features ........................................................................................................................... 03
TMS 9918 VDF ............................................................................................................................................. 04
TMC 0430 Graphics ROM ..................................................................................................................... 05
TIM 9919 Sound Generator ............................................................................................................. 06
System Power Up ................................................................................................................................................ 07
Debug Check List ............................................................................................................................................. 08
Cassette Interface ....................................................................................................................................... 09
General Description ...................................... 10
Oscillator Circuit ........................................................................................................................... 13
CPU ....................................................................................................................................................................... 15
Memory Selection Logic ...................................... 34
Memory Map ...................................................................................................................................................... 36
ROM and RAM Memory ......................................................................................... 37
16 To 8 Bit Interfacing Circuit ........................ . .......................................................... 39
Graphic Read Only Memory (GROM) ........................................................ . .......................... 48
TMS 9901 Programmable System Interface ................................................................. 54
Video Display Processor ........................................................................................................... 64
Sound Generation Controller ............................................................................................... 73
Keyboard & Remote Handheld Control Unit Interfacing ........................... 78
Cassette Interfacing Circuitry ........................................................................................ 79
I /0 Bus ..................................................................................................................................................... 81
Power Supply Board .......................................................................................................................... 84
Trouble Shooting Guide ............................................................................................................................ 86-
I/O Fort Connector .......................................................................................................................................... 104
GROM Port Connector ....................................................................................................................................... 105
Cassette 1/0 Fort ........................................................................................................................... 106
RAM Trap ....................................................................................................................................................................... 107
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