Tandy 26-3334 User manual

I '
\_,!
TABLE
OF
CONTENTS
SECTION
I.
GENERAL
1.1
1.
2
1.3
1.4
1.5
1.6
Introduction.......
5
System
Description
5...,.
Memory Map • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 8
I/O
Control
Registers
•••••••.••.•••••••••••••
9
Chip
Control
Registers
•••••••.••••••.•••••.
11
68B09E
Vector
Registers
•••••••••••••••••..•
22
SECTION
II.
SPECIFICATIONS
2.1
2.2
Technical
Physical
•••.•...•...••..••.•.
'
...•.•••......
23
.....
25
SECTION
III.
DISASSEMBLY/ASSEMBLY
3.1
3.2
3.3
Disassembly
..................................
26
Assembly
.....................................
26
512K
RAM
Upgrade
Instructions
••••••••••••••••
27
SECTION
IV.
BLOCK
DIAGRAM
4.1
4.2
NTSC
Version
..••.•.••.•...•..........•...•...
28
PAL
Version
..•.......•.••.......•••...••....•
29
SECTION
V.
THEORY
OF
OPERATION
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
5.9
5.10
5
.11
5.12
5
.13
5.14
5.15
MC68B09E/MBL68B09E/HD68B09E
(ICl)
•••••••••••••
30
Memory
(RAM)
•••••••••••
·
•••••••••••••••••••••
•34
TCC1014
(VC2645QC)
•••••••••••••••••••••••••••
36
PAL
Encoder
(PAL
Version
Only)
•••••••••••••••
38
PIAs (IC4 and IC5)
•••••••••••••••••••••••••••
39
K~yboard
Interface
(ICS)
••••••••••••••••••••••
40
ROM
(
IC
2)
••••••••••••••••••••••••••••••••••••
41
DAC
Circuitry
(IC7)
••••••••••••••••••••••••••
42
SALT
Circuitry
..•................•..........
. 44
Cassette
Tape Format
Information
••••••••••••
47
RS-232C
Connector
(JK3)
••••••••••••••••••••••.
47
Cartridge
Connector
(CNl)
••••••••••••••••••••
49
Power
Transformer
•.••....•.•.•..•..•....•..•••
52
Joysticks·
..........................•.........
52
TV
Switch
Box
(NTSC
Version
Only)
••••••••••••
53
SECTION
VI.
TROUBLESHOOTING
6
.1
6.2
Introduction
•••••••••••••••.••••••••••••••••••
54
Video
Problems
................................
55
No
Display/No
Sync/Noisy
Video
..••.••••••••••
55
Wrong
Color
.................................
55
No
Color
....................................
55
Random
Character/Clear
Screen/No
Sign-on
••••
55
RGB
Problem
...•......................
•
..
•
....
55
Composite Video
Signal
Adjustment
(PAL
Version
Only)
•••..••••••..•.•...•••••••
56
-2-

u
u
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6
.10
Keyboard Problems
••••••••..•••.••••••.
.56
.56
No
Keyboard Entry/Wrong
Character
Processing
Problem
Cassette
Problems
••••••
Motor
Write
Control
Problem
Problem
Read
Problem
RS-232C
Problem
Sound
Problem
Joystick
Problem
Cartridge
Problem
•••
56
•••
56
••••
56
••••
56
•••
56
••
57
•••••••••••
57
•.•••••••••
5
7
••••
57
Power
Supply
Check
••••••••••••••••••••
•
•••
58
NTSC
Ve
rs
ion
•••.•.••••.••.••.••..•••.•••••••••
58
PAL
Version
•••
61
6.11
Major Waveforms
NTSC
Version
PAL
Version
•••••
64
••••••
64
••••••
70
SECTION
VII.
512K
EXPANSION
RAM
CARD
PCB
VIEWS
•••••••••••••••••••••••••••••••••••••
78
ELECTRICAL
PARTS
LIST
•••••••••••••••••.•••
79
SECTION
VIII.
NTSC
VERSION
PCB
VIEWS
•••••••••••••••
ELECTRICAL
PARTS
LIST
EXPLODED
VIEW
PARTS
LIST. ...............
...............................
EXPLODED
VIEW
SEMICONDUCTOR
INFORMATION
.82
.84
••
90
••
91
•••••••
93
SCHEMATIC
DIAGRAM•••••••••••••••••
•••••••
103
SECTION
IX.
PAL
VERSION
PCB
VIEWS
••••••••••••••••
••••••..••.•••••
108
ELECTRICAL
PARTS
LIST
EXPLODED
VIEW
PARTS
LIST•
• • • • • • . . • • • • • • • • • . • • • •111
•...•...•..••.•••.••••
119
• • • • • • • • • • • • • • • • • • • . • • • • • • • • • • •
•.
. 121
EXPLODED
VIEW
SEMICONDUCTOR
INFORMATION
SCHEMATIC
DIAGRAM
•••••••••
••••••
122
•
•••••
126

1-1.
1-2.
1-3.
3-1.
3-2.
3-3.
3-4.
4-1.
5-1.
5-2.
5-3.
5-4.
5-5.
5-6.
5-7.
5-8.
5-9.
5-10.
5-11.
5-12.
5-13.
5-14.
5-15.
5-16.
LIST
OF
FIGURES
Color
Computer 3
Installation
•••••••••••••••
7
Color
Computer 3
Memory
Map
•••••••••••••••••
8
Memory
Map
for
SAM
Control
Register
•••••••••
21
Removal
of
Top Cover
...........•....••.•.•••
26
Removal
of
Main
PCB
...........•..••....•..••
26
Main
PCB
•••••••.••••....••.••••••••••••••••
•
27
512K
RAM
Card
•••••••••••••••••••••••••••••••
27
Block
Diagram
•..••.•••..•••.•••..••••••••••.
28
NTSC
Version
..•••••••••.•••.•••••.•.•..••..
•
28
PAL
Version
•..•.•.••••.•...•..•.•.•..•...•••
29
MC68B09E
Progranuning Model
••••••••••••••••••
30
MC68B09E
Pin
Assignments
••••••••••••••••••••
31
MC68B09E
Read/Write
Timing
at
0.89
MHz
••••••
33
DRAM
Block
Diagram
..•.•..•••.••.•.•.••••••••
34
DRAM
Timing
...................................
. 35
Color
Computer 3
Address
Decoding
•••••••••••
36
MMU
Block
Diagram
....••..•...•..........•..•
. 37
PIA
Block
Diagram
•••••••••••••••••••••••••••
39
Color
Computer 3 Keyboard
Array
•••••••••••••
40
DAC
Block
Diagram
(IC7)
•••••••••••••••••••••
42
SALT
Block
Diagram
(IC8)
••••••••••••••••••••
44
Color
Computer 3 Power
Supply
•••••••••••••••
45
I/O
Circuitry
•••••••••••••••••••••••••••••••46
RS-232C
Connector
Pinout
••••••••••••••••••••
48
Joystick
Schematic
••••••••••••••••••••••••••
52
Antenna
Switch
Box
Schematic
•••••••••••
.-
••••
53
LIST
OF
TABLES
1
Line
Printer
Variables
••••••••••••••••••••••
50
2
Alternate
Line
Printer
Variable
Values
••••••
50
3
Cartridge
Connector
Signals
•••••••••••••••••
51
-4-
'.))
'·.,
__
,/

SECTION
I.
GENERAL
1.1
Introduction
The
Color
Computer 3
is
a
refined
version
of
Tandy's
popular
Color
Computer
2.
It
is
designed
to
provide
the
same
reliable
operation
as
its
predecessor,
but
it
incorporates
the
latest
in
electronic
technology.
Figure
1-1
shows a
typical
installation
of
the
Color
Computer
3.
The
Color
Computer 3
contains
an
internal
BASIC
program
in
ROM
which
is
accessed
when
the
unit
is
powered
up.
Other
program
modules/cartridges
may
be
inserted
into
the
receptacle
on
the
right
side
of
the
unit.
An
optional
Multi-pak
Interface
module
allows
up
to
four
program
paks
to
be
installed
at
the
same
time,
with
selection
of
the
specific
module
active
at
any
one
time
selected
either
by
software
or
by a
switch
on
the
Multi-pak
Interface.
Additional
peripheral
devices,
such
as
an
external
disk
drive,
may
be
added
to
the
Color
Computer 3
for
additional
memory
storage
and
retrieval.
All
input
and
output
ports
for
the
Color
Computer
3,
with
the
exception
of
the
program
module/cartridge
slot
and
the
RGB
monitor
output
(for
CM-8),
are
located
on
the
rear
panel
of
the
unit.
These
include
the
joystick
input
ports
(right
and
left),
Serial
I/O,
Cassette
I/O,
TV
output
jack
(for
standard
color
television
set
and
composite
monitor),
POWER
ON/OFF
switch
and
RESET
switch.
A
recessed
channel
switch
(for
selecting
either
channel
on
the
TV
-
3/4
for
NTSC
and
1/2
for
PAL
version)
is
also
located
on
the
rear
panel
of
the
unit.
'
Note:
Before
installing
any
peripheral
device,
always
remember
to
unplug
the
Color
Computer's
power
cord.
This
wilT'prevent
damage
to
the
device
or
to
the
Color
Computer
3.
1.2
System
Description
The
primary
functions
of
the
Color
Computer 3
are
performed
by
four
Large
Scale
Integration
eLSI)
chips,
plus
Random
Access
Memory
(RAM)
and
Read
Only
Memory (ROM).
These
four
chips
are
labeled
on
the
block
diagram
as
CPU,
ACVC
and two
PIAs.
With
only
these
four
chips,
plus
Random
Access
Memory
(RAM),
Read Only
Memory
(ROM)
and
a power
supply,
the
Color
Computer 3
will
operate
and
provide
video
output
(RF,
Composite,
Analog
RGB). However,
to
allow
communication
with
the
outside
world,
I/O
interfaces
must
be
added.
The
main
component
of
any
computer
system
is
the
Central
Processing
Unit
(CPU,
ICl).
It
is
the
function
of
the
CPU
to
provide
or
request
data
and
select
the
proper
address
for
this
data.
In
addition,
the
CPU
is
capable
of
performing
a
limited
set
of
mathematical
and
logical
operations
on
the
data.
ROM
(IC2)
has
the
function
of
providing
the
CPU
with
a
predefined
set
of
instructions.
Without
ROM,
the
CPU
would
run
wild
and
randomly
execute
instructions.
In
normal
operation,
the
CPU
jumps
to
the
start
address
in
ROM,
after
the
reset
switch
has
been
pressed,
and
then
performs
the
reset
program
to
set
up
all
of
the
programmable
devices.
Following
this,
the
BASIC
interpreter
residing
in
ROM
is
in
control
of
the
CPU.

RAM
(IC16
-IC19)
provides
storage
for
the
programs
and/or
data
currently
being
executed.
In
the
standard
unit,
these
four
ICs
are
64K
x 4
but
may
be
upgraded
to
sixteen
256K
x 1 ICs
as
an
option.
(See
Paragraph
3.3
on
page
28
for
instructions.)
In
addition,
the
same
RAM
is
used
to
generate
the
video
display.
Normally,
no
conflict
will
be
observed
because
the
program
will
use
one
portion
of
RAM
and
the
display
will
use
another.
During
normal
usage,
the
BASIC
interpreter,
located
in
ROM,
will
control
the
execution
of
programs
located
in
RAM.
A
central
component
in
the
Color
Computer 3
is
the
Advanced
Color
Video
Chip
(IC6).
This
chip
provides
refresh
and
address
multiplexing
for
the
RAM.
It
also
provides
all
of
the
system
timing
and
device
selection.
ACVC
comprises
the
VDG
(Video
Display
Generator)
function
which
supports
High-Resolution
mode,
in
addition
to
I
all
other
modes
included
in
the
Color
Computer
2.
Dhring
High-Resolution
mode,
it
gene~ates
40 x 24
or
80 x 24
text
screen,
knd 320 x 192
or
640 x
192
graphics
Screen.
It
is
also
designed
to
ohtput
two
different
video
signals
I -
composite
video
and
analog
RGB.
I
ACVC
can
expand
memory
space
up
to
512K
bytes.
Hkving
a
built-in
MMU
(Memory Managkment
Unit),
it
can
I
support
2
banks
of
256K-byte
RAM,
each
with
a
9rline
address
bus,
even
though
the
CPU
possesses
only
16
address
linesl
I
The
remaining!
circuitry
in
the
Color
Computer 3
is
devoted
to
Input/Output
(I/O)
communication.
The
most
important
part
of
this
circuitry
is
the
keyboard,lwhich
allows
the
operator
to
enter.information.
Other
I/O
circuits
1re
provided
to
allow
joystick
input,
cassette
input
and
I •
output,
and
Rr-232C
input
and
output.
-6-

c
i
MODEM
SERIAL
PRINTER
•
c·
TV
CASSETTE RECORDER
~
'"?Q;~'h,.,rf'Rr\'~~
J
e:r{W~
COLOR COMPUTER 3
RIGHT
LEFT
JOYSTICK JOYSTICK
,,
.....
/.
.·
/
VIDEO
AUDIO
'-!
=
[[[[]
D
Ill
0
'\
......
[2J
'=-
PROGRAM
PAK
I I
--1
MUL
Tl-PAK
{
...)
c::__=i
INTERFACE
:~:--1~
l
I
I
,_
")
Figure
1-1.
Color
Computer 3
Installation
r
MONITOR
ANALOG
RGB
MONITOR
CM-8

1.3
Memory
Map
Figure
1-2
shows
the
breakdown
of
the
large
blocks
of
memory
in
the
Color
Computer
3.
The
rest
of
the
section
itemizes
the
following
registers:
•
1/0
Control
Register
•
Chip
Control
Register
• 68B09E
Vector
Register
S7FFFF
S7FFOO
S7EOOO
S7COOO
S7AOOO
$78000
$70600
$70400
$70000
S6EOOO
S6COOO
$68000
$60000
$00000
,...._
'
6
c
R
SUPER EXTENDED BASIC
CARTRIDGE ROM
COLOR BASIC
EXTEND COLOR BASIC
STANDARD TEXT SCREEN
.
HIGH RESOLUTION
TEXT SCREEN
HIGH RESOLUTION
GRAPHIC SCREEN
-=::::
8809E
VECTOR,
ONTROL
EGISTER, 1/0
Figure
1-2.
Color
Computer
3
Memory
Map
-8-
Q
N
~
2
0
a:
Q
.(0
~
2
<1'.
a:
'!)
:::J
0
a:
I-
z
0
u
c5
::::::
~
0
a:
I-
a..
w
u
x
!:!:!.
l£
N
~
~)
l!l
2
<1'.
a:

u
(
\_)
1.4
I/O
Control
Registers
FFOO
-FF03 PIA
IC5
FFOO:
FFOl:
FF02:
FF03:
BIT 0
=
BIT
1
=
BIT
2
=
BIT 3
BIT 4
=
BIT
5
=
BIT
6
=
BIT
7
BIT 0
BIT 1
BIT 2
=
BIT
3
=
BIT 4
=
BIT 5
=
BIT 6
=
BIT 7 =
KEYBOARD
ROW
1 and
right
joystick
switch
1
KEYBOARD
ROW
2 and
left
joystick
switch
l
KEYBOARD
ROW
3 and
right
joystick
switch
2
KEYBOARD
ROW
4 and
left
joystick
switch
2
KEYBOARD
ROW
5
KEYBOARD
RO}'l
6
KEYBOARD
ROW
7
JOYSTICK
COMPARISON
INPUT
Control
of
HSYNC
(63.
Sµs) { 0
1 =
IRQ*
to
CPU
Disabled
Interrupt
=
IRQ*
to
CPU
Enabled
Control
of
Interrupt
{
o
1
=
Flag
set
on
the
Polarity
falling
edge
of
HS
=
Flag
set
on
the
Normally 1:
SEL
1:
1 Always
I Always
Not
used
rising
edge
of
HS
0
=
Changes
FFOO
to
the
data
direction
LSB
of
the
two
analog
MUX
select
lines
Horizontal
sync
interrupt
flag
BIT 0 =
KEYBOARD
COLUMN
1
BIT
1
=
KEYBOARD
COLUMN
2
BIT 2
=
KEYBOARD
COLUMN
3
BIT 3
=
KEYBOARD
COLUMN
4
BIT 4
=
KEYBOARD
COLUMN
5
BIT
5 =
KEYBOARD
COLUMN
6
BIT
6
=
KEYBOARD
COLUMN
7/RAM
SIZE
OUTPUT
BIT 7 =
KEYBOARD
COLUMN
8
register
BIT 0
Control
of
VSYNC
(16.667ms) {
Ol
=
IRQ*
to
CPU
Disabled
Interrupt
=
IRQ*
to
CPU
Enabled
BIT
1
Control
of
Interrupt
Polarity
.(
o
1 =
sets
flag
on
falling
edge
FS
BIT
BIT
BIT
BIT
BIT
l =
sets
flag
on
rising
edge
FS
2
=
NORMALLY
1: 0
=
changes
FF02
to
the
data
direction
register
3
=
SEL
2:
MSB
of
the
two
analog
MUX
select
lines
4 =
5
=
6
1 Always
1 Always
Not
used
BIT 7 =
Field
sync
interrupt
flag
-9-

FF20 -FF23 PIA IC4
FF20:
FF21:
FF22:
FF23:
BIT 0
CASSETTE
DATA
INPUT
BIT 1
=
RS-232C
DATA
OUTPUT
BIT 2 6 BIT
D/A
LSB
BIT 3 = 6 BIT D/A
BIT 4 6 BIT D/A
BIT 5 = 6 BIT D/A
BIT 6
=
6 BIT D/A
BIT
7 =
6 BIT
D/A
MSB
BIT 0
Control
of
the
CD
(RS-232C
status)
Interrupt
{~:
FIRQ*
to
CPU
Disabled
FIRQ*
to
CPU
Enabled
Control
of
Interrupt
{0
1 =
sets
flag
on
falling
edge
CD
Polarity
=
sets
flag
on
rising
edge
CD
BIT 1
BIT
BIT
BIT
BIT
BIT
BIT
2 =
Normally
1:
0 =
changes
FF20
to
the
data
direction
register
3 =
Cassette
Motor
Control:
0 =
OFF
1 =
ON
4 = 1 Always
5 = 1 Always
6 = Not Used
7 =
CD
Interrupt
Flag
BIT 0 = RS-232C
DATA
INPUT
BIT 1 =
SINGLE
BIT
SOUND
OUTPUT
BIT 2 =
RAM
SIZE
INPUT
BIT 3 =
RGB
Monitor
Sensing
INPUT
BIT 4 =
VDG
CONTROL
OUTPUT
BIT
5 =
VDG
CONTROL
OUTPUT
BIT 6 =
VDG
CONTROL
OUTPUT
BIT
7 =
VDG
CONTROL
OUTPUT
BIT 0
Control
of
the
Cartridge
Interrupt
BIT 1
Control
of
Interrupt
Polarity
BIT 2
Normally
1:
0 =
changes
BIT 3 = Sound
Enable
BIT 4
=
1 Always
BIT 5 = 1 Always
BIT 6 = Not
used
BIT 7
=
Cartridge
Interrupt
Flag
css
GMO
&
UPPER/LOWER
CASE*
GMl
&
INVERT
GM2
A*/G
{~
{~
FF22
= FIRQ*
to
CPU
Disabled
= FIRQ*
to
CPU
Enabled
=
sets
flag
on
falling
edge
CART*
=
sets
flag
on
rising
edge
CART*
to
the
data
direction
register
'FF40 -FFBF: Not
used
Note:
FF22, FF23
are
duplicated
in
tccl014
(VC2645QC),
and
V.D.G
Control
Bit
(Bit
3
through
Bit
7)
affects
this
IC (TCC1014)
only
•
.....
-10-