Tandy 1000 Technical Reference Manual

Tandy 1000
MC6845
Technical Reference Manual
ELECTRICAL CHARACTERISTICS (Vee" 5.0 V ±5%, VSS" 0, TA" 0 '0 70
0
e unless
o'herwise no'ed)
Characteristic
Svmbol
Min Typ Max
Uoit
Input High Voltage
VIH
2.0
Vee
Vde
Input Low Voltage
VIL
-0.3 0.8 Vde
I nput Leakage Current
lin
1.0
2.5
~Adc
Three-5'a'e (Vce " 5.25 VI
ITSI
-10
2.0
10
~Adc
(Vin" 0.4 '0 2.4 VI
Output High Voltage
VOH
Vde
(I load " -205 ~AI
00-07 2.4
(I load " -100 ~AI
Other Outputs :2.4
Output Low Voltage
VOL
0.4 Vde
(I load " 1.6 mAl
Power Dissipation
Po
600 mW
Input Capacitance
Gin
pF
00-07 12.5
All others 10
Output Capacitance
All Outputs
C
out
10 pF
Minimum Clock Pulse Width, Low
PWCL
160
Minimum Clock Pulse Width, High
PWCH
200
Clock Frequency
Ie
2.5
MHz
Rise and Fall Time for Clock Input
ter,tcf
20
Memory Address Delav Time
'MAO
160
Raster Address Delay Time
'RAO
160
Display Timing Delay Time
'OTO
300
Horizontal Sync Delay Time
'HSO
300
Vertical Sync Delay Time
'VSO
300
Cursor Display Timing Delay Time
'COO
300
Light Pen Strobe Minimum Pulse Width
PWLPH
100
Light Pen Strobe Disable Time
'LP01
120
'LP02
Note: The light pen strobe must fall to low level before VSYNC pulse rises
BUS TIMING CHARACTERISTICS
Characteristic
Symbol Mio Max
Unit I
READIWRITE
E(lable Cycle Time
teyeE
1.0
~,
Enable Pulse Width. High
PWEH
0.45 25
",
Enable Pulse Width, Low
PWEL
0.43
~,
Setup Time, CS and RS valid to enable positive transition
'AS
160
Data Delay Time
'OOR
320
Data Hold Time (Read)
'H
10
(write)
10
Address Hold Time
tAH
10
Rise and Fall Time for Enable Input
tEr, tEf
25
Data Setup Time
tosw
195
Data Access Time
'ACe
480
® MOTOROLA BeWl'conductor Products Inc.

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