Tandy 1000 Technical Reference Manual

Tandy 1000
Technical Reference Manual
8259A/8259A-2/8259A-8
A.C. CHARACTERISTICS (Continued)
----~82s9A.8 --~59A . 1 8259A:2 T --~-T" .... ~-
Symbol Parameter Min'IM~;-Mj; TMax. I Mint~TMax.i un,tStTest Conditions
.TCHCL End~f-c-ommand--;o~e~~C;;;m;';;d--;~;--s~o~t--- f-
soo
., f n~ -
(Not same
command type) I
End of INTA sequence to next I I I'
INTA sequence.
• Worst case timing for TCHCL in an actual microprocessor system is typically much greater than 500 ns (I e. 8085A = 1.6I-'s.
8085A-2 = 11-'s. 8086 = 11-'s, 8086-2 = 625 ns)
NOTE: This IS the low time required to clear the input latch In the edge triggered mode
TIMING RESPONSES
Symbol
Perameter
8259A-8 8259A 8259A-2
Units reet Conditione
Min.
".x.
TRLDV
Dala Valid from RDilNTA[ 300
TRHDZ
Dala Floal alter RD/INTAI 10 200
TJHIH Interrupt Output Delay
400
TIALCV
Cascade Valid from FirstlNTAI
565
(Masler Only)
TRLEL
Enable Active from ROt or INTAj
160
TRHEH Enable Inactive from RDj or INTAf 325
TAHDV Data Valid from Siable Address 350
TCVDV Cascade Valid to Valid Data 300
Min. Max. Min.
Max.
200
'20
10 100
10 85
350
300
565 360
125
100
150
150
200
200
300
200
C -of Data Bus=
100 pF
C of Data Bus
Max text C = 100 pF
Min lest C = 15 pF
C\I'H = tOO pF
CCASCADE := 100 pF
A.C. TESTING INPUT, OUTPUT WAVEFORM
A.C.
TESTING LOAD CIRCUIT
,.
04S=X::> TEST POINTS < ::x=
C
L
100 pF
C
L
INCLUDES JIG CAPACITANCE
WAVEFORMS
DATA lUI
W~---------""'\
WRITE
Ci--------,.
ADOllE.IUI
At ---J "'---+---------H-..Jl
2-135

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