Atari 800

Motherboard
Console
-
^QO
The
*00
Console
Motherboard
contains
the
Pot
Keyboard
(POKEY)
(AiOl)
chip
,
the
Peripheral
Interface Adaptor
chip (PIA) (A102),
the ROM
Personality
chips {A1Q3
thru
A105),
the Keyboard Key-In/Key-Out
analog
multiplexers,
the Memory
Map
Decoder
(Z103),
the
controller
jacks (JlOl
thru JIO*),
the CPU
connector
jack (JllO), the
Keyboard
connector
jack, RAM
connectors
and Cartridge
connectors-
Pot
Keyboard
Integrated
Circuit
The Pot
Keyboard
Integrated
Circuit (POKEY)
provides
the Interface
between
the
Keyboard,
the
Serial I/O
ports,
and the
microprocessor.
It
also contains
four semi-
independent
audio
channels,
each with
its own
frequency,
noise,
and volume
control.
Figure
i-6
shows
the pin
assignments
of the POKEY.
Ground
Data
Bus
Data
Bus
Data Bus
Data Bus
Data Bus
Phase
2
Clock
Put
Scan
Pot
Scan
Pot
Scan
Pot
Scan
Pot
Scan
Pot
Scan
Pot
Scan
Pot
Scan
Keyboard
Scan
5
V
Power
Keyboard
Scan
Keyboard
Scan
Keyboard
Scan
VSS
D3
D*
D3
06
D7
02
P6
P7
P*
P5
P2
P3
PO
PI
K^
VDD
kJ
K3
*0
D2
39
Di
3S
DO
37
AUDIO
36 AO
35
Al
34
A2
33 A3
32
R/W
31
CSl
30
CSQ
29 IRQ
28
SOD
27
OCLK
26
BCLK
25
KRl
2*
SID
23
KO
22
m
21
K2
Data Bus
Data Bus
Data Bus
Audio
Out
Address Bus
Address
Bus
Address Bus
Ac^iiress
Bus
Read/Write
Control
Chip
Select
Chip
Select
Interrupt
Request
Serial
Output
Data
Serial
Output
Clock
Bidirectional
Clock
Keyboard
Scan
Serial
Input
Data
Keyboard
Scan
Keyboard
Scan
Keyboard
Scan
Figure 1-6.
POKEY
Pin
Assignments
Peripheral
Interface
Adaptor
The
Peripheral
Interface
Adaptor
(PIA)
(6520) has
two
8-bit
programmable
I/O
ports
and two
control
bits for
each
port, for
a
total of ten
lines
per
port.
Figure
1-7
shows
the
pin
assignments
of the
PIA.
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