Tandy 1000 Technical Reference Manual

Tandy 1000
Technical Reference Manual
AUDIO OUT 0
From Extemal Sound Source
Load:
10k ohms.
To Extemal Source
Drive: 1.25 Volts
P-P into 10K
INTERRUPT REQUEST#4
SOURCE: OPEN-COLLECTOR
OR 3-STATE BUFFERS
Load: 1 ULand 1.0K ohm
pull-up. 10/0.9 UL
Set LOW by Peripherals (I/O or
Memory) to extend READ or
WRITE cycles.
Power On or Manual
SOURCE:
U82
Drive: 75/7.5 UL
From extemal masters
Load: 1 ULand 10K ohm
pull-up. 10/0.9 UL
To extemal masters
SOURCE: U82
Drive - 75/7.5
UL
INTERRUPT REQUEST#2 To system interrupt controller
INTERRUPT REQUEST#3 Load: 1
UL and 2.2K
pull-down
o BUS GRANT
I BUS REQUEST
o SYSTEM RESET
I SYSTEM WAIT
AEN
IR4
AUDIO IN
BREQ*
IR2
IR3
RESET
READY
1 MOS load 40/160 UL
Dedicated output
acknowledges from DMA.
Drive:
8237 A-5/9517A
2/2
UL
Load: 8237 A-5/9517A
REFRESH*
DACK1 *
FDCDACK*
DACK3*
DR03
DR01
The following are not sourced by the CPU but are to be SOURCED (0) Output
or LOADED (I) Input by an extemal DMA source
RFSHRQ I REQUEST DMA Dedicated input requests
CHANNEL#O to DMA
REQUEST DMA
CHANNEL#1
FDCDMARQ I REQUEST DMA
CHANNEL#2
REQUEST DMA
CHANNEL#3
o ACKNOWLEDGE DRQO*
o ACKNOWLEDGE DRQ1 *
o ACKNOWLEDGE DRQ2 *
o ACKNOWLEDGE DRQ3 *
DMATC
o TERMINAL COUNT
Used by DMA Controller to
indicate Terminal Count
reached.
Drive: 2/2 UL
+ 5VDC + 5VDC ± 4% 3.0 Amps available on the bus.
+ 12VDC + 12VDC ± 5% 0.5 Amps available on the bus.
-12VDC - 12VDC + 8.3% - 25% 0.06 Amps availabie on the bus.
GROUND Power Retum for + 5, + 12, -12 VDC.
14

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200